932-1005 Detector Participants Guide

Participant’s GuideTechnical Training

932-1005

Integrated Genset Controls

11/2000

IntroductionIntegrated Generator Set Controls

I-1Participant’s Guide

Integrated Generator Set Controls ModuleTable of Contents

Section 1

Introduction I-1. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

The introduction describes the audience, the purpose, and the structure ofthe training module.

Lesson: Fundamentals of Generator Set Controls F-1. . . . . . . . . . . . . . . . . .

Participants review principles of generator set control systems.

Lesson: Detector Control Front Panels 1-1. . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Participants learn the standard and optional components in the DetectorControl front panels.

Lesson: Cummins / Onan Diagrams 2-1. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Participants learn how to identify the different diagrams used by Cum-mins Power Generation and their uses.

Lesson: DC Control Inputs & Outputs 3-1. . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Participants learn to identify the components on the ECM board and theirfunction, and the main input and output signals for the ECM.

Lesson: Troubleshooting the DC Control 4-1. . . . . . . . . . . . . . . . . . . . . . . . . . .

Participants learn the sequence of operation of the Detector Control ECMand where to check for signals which indicate proper or improper func-tion of the ECM.

Lesson: Detector ECM Simulator 5-1. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Participants use the learning from the previous lessons to assemble andtest the operation of a Detector Control.

Lesson: Auxiliary Relay Board (ARB) 6-1. . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Participants learn the components, function, and function of the jumperson the ARB.

Cummins is a registered trademark of Cummins, Inc.

Integrated Generator Set ControlsIntroduction

I-2 Participant’s Guide

Lesson: AC Control Inputs, Outputs, and Troubleshooting 7-1. . . . . . . . . .

Participants learn to identify the components on the Automatic VoltageRegulator (AVR), their function, and the main input and output signalsfor the AVR.

Lesson: Automatic Voltage Regulator Adjustments 8-1. . . . . . . . . . . . . . . . .

Participants learn how to identify the different adjustment potentiometerson common Cummins/Onan AVRs and how to properly adjust the AVRs.

Lesson: Alternator Reconnection Diagrams 9-1. . . . . . . . . . . . . . . . . . . . . . . .

Participants learn how to reconnect alternator windings and interpret re-connection diagrams.

Lesson: AC Control Troubleshooting 10-1. . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Participants learn how to troubleshoot the AC Control and alternator.

IntroductionIntegrated Generator Set Controls

I-3Participant’s Guide

Introduction

Welcome! Welcome to the Participant’s Guide for the IntegratedGenerator Set Control module! This guide was written byCummins Power Generation’s Sales and Technical Trainingdepartment for your use and reference.

We suggest you read through the entire Introduction tobecome familiar with the guide’s structure. Then, justfollow along in the guide during your training session.

Module Purpose The purpose of the Integrated Generator Set Control

module is to help you, the Cummins Power Generationdistributor technician understand the use, operation, serviceand troubleshooting of the Integrated Generator SetControl.

With this information, you will be better prepared to meetyour customers’ varying needs.

Module Audience This module was written for Cummins Power Generationdistributor power generation technicians, and customertechnicians, who have previous experience with orknowledge of Integrated generator sets.

Module Structure This module contains lessons on related topics. Each lessonfollows a carefully designed training format, including awarm up, presentation, and activity (or exercise).

Lesson Format

Warm ups help you focus and begin thinking about thelesson topic. The presentation portion of the lesson iswhere you receive new information. The activity followsthe presentation; it gives you the chance to practice newskills or work with new ideas.

Module Assessment

After completing all the lessons in the module, you willcomplete a module assessment. The module assessment lets

Integrated Generator Set ControlsIntroduction

I-4 Participant’s Guide

us evaluate the level of knowledge you have on the topicafter completing the module.

Module Comment Form

You will also complete a module comment form. This formgives you the chance to comment on the usefulness andeffectiveness of the training module and make suggestionsfor improvements.

We will use the results from the module assessment andmodule comment form to help us determine if there is aneed to modify the module.

Lesson: Generator Set Control FundamentalsIntegrated Generator Set Controls

F-1Participant’s Guide

Lesson: Generator Set Control Fundamentals

This lesson presents an overview of the Detector series of generator set controls.

Objectives

After completing this lesson, you should be able to:

• State the purpose of the generator set control.

• State the purpose of the Automatic Voltage Regulator (AVR).

• State the purpose of the Engine Governor.

• List the main circuits of the ECM.

• List the main functions of the Run circuit.

• Describe what circuits and components are powered during the Start mode of operation, andwhat removes power to them.

• State the point of change from Start to Run circuits in the Detector controls.

• State when the oil pressure and coolant temperature can cause warnings or faults to appear.

• State which faults can occur during the Start circuit operation.

• List the inputs required to light the local and remote Run lamps.

Onan is a registered trademark of Onan Corporation.

Lesson: Generator Set Control Fundamentals Integrated Generator Set Controls

F-2 Participant’s Guide

Slide F-1 Detector-12 Generator Set Control

Generator Set Control Fundamentals Quiz

1. What is the purpose of the generator set control?

2. List three major circuits of a generator set control.

3. List the control switch positions for manual and automatic operation.Manual: Automatic:



Three parts of a Genset Control

AVR ECM

GovernorControl

Slide F-2 Detector-12 Generator Set Control and Engine

What does a generator set control do?

Automatic Voltage Regulator (AC Control)

• Monitors Generator Set Output Voltage.

• Controls Excitation to Alternator.

• Protects AVR and Alternator Wiring.

Engine Control Monitor (DC Control)

• Monitors Engine Operation.

• Protects Engine if Oil Pressure or Coolant Temperature go out of normal range.

Engine Governor Control

• Maintains steady engine speed when load is increased and decreased



DC Start Circuits

ECM

Slide F-3 DC Start Circuits

The DC Start Circuit

Engine Systems

• Fuel System

• Ignition System

• Governor System

• Cranking Solenoid and Motor

• Monitor Primary Faults

Cooling System

• Dampers and Louvers

• City Water Cooling



DC Run Circuits

ECM

Slide F-4 DC Run Circuits

The Run Circuits

Starter Disconnect SignalsDC Starter Disconnect

(DC Alternator - Cummins sets)(Generator RPM pickup - Kubota sets)

AC Starter Disconnect (TB21-21 & TB21-32)

Local Run Light = Two Starter Disconnect Signals

Remote Run Light = AC Starter Disconnect Signal



DC Stop Circuit

ECM

Slide F-5 DC Stop Circuit

The DC Stop Circuit: Shutdown

When the Operator moves S12 to the Stop position, A11 K7 and A11 K2 are de-energized, Thisremoves Switched B+ from Engine Terminal 26.

When Switched B+ is removed from T-26, the Fuel, Governor and Ignition systems are turnedoff.

The Diesel engine stops because the fuel is turned off.

The Gasoline or Gaseous fuel engine stops because the fuel and ignition systems are turned off.



DC Faults

ECM

Slide F-6 DC Faults

The DC Stop Circuit: Faults

STANDARD OPTIONAL

MONITOR INFORM PROTECTAlarms Faults

MONITOR INFORM PROTECTAlarms Faults

Remove Switched B+ from:

Stops genset on:



Genset Control Introduction Quiz

1 What is the purpose of the generator set control?

2. List the three main circuits of the ECM.

3. List the three key functions of the RUN circuit.

4. The START mode of the ECM provides power to what components and/or circuits?

5. What is the change-over point from the START circuit to the RUN circuit?

6. When does the ECM start looking at Oil Pressure and Coolant Temperature for warnings and faults?

7. What removes the starter pilot signal when the engine reaches approximately 350 – 550 RPM?

8. What is the fault that occurs if the control does not get an AC or DC starter disconnect signal?

9. What signals tell the Engine Control Monitor (ECM) to check the engine for low oil pressure, and when?

10. What is required to have the local RUN lamp light?

Lesson: Detector Control Front PanelsIntegrated Generator Set Controls

1-1Participant’s Guide

Lesson: Detector Control Front Panels

This lesson presents an overview of the Detector Control front panels.

Objectives


• Identify standard and optional components on Detector Controls.

• Describe the numbering system used inside the Detector Control.

• Identify the components which come as part of the Meter Kit.

• Identify those AC panel components which must be ordered separately from the Meter Kit.


Lesson: Detector Control Front Panels Integrated Generator Set Controls

1-2 Participant’s Guide

Detector 7 Control

Slide 1-1 Detector-7 Control

Detector Control standard components

In the blanks below, fill in the designation of the component which matches the description nextto the blank.

Lamp Test/Reset switch

Run/Stop/Remote switch

Panel Lamp

Indicator Lamp bar (7 lights)

Oil Pressure gauge

Water Temperature gauge

Battery Voltmeter

Running Time meter



Detector 12 AC Control Panel

Slide 1-2 Detector-12 AC Control Panel

Optional AC Control items:

In the blanks below, fill in the designation of the component which matches the description nextto the blank. * = Included in the Meter Package with a new door and wiring harness.

* AC Voltmeter.

AC Ammeter.

* Frequency meter.

* Adjust voltage ±5%.

* Tell Operator to read proper meter scale (upper or lower).

* Switch Ammeter and Voltmeter to different output phases.

Wattmeter.

Power Factor meter.



Detector 12 DC Control Panel

Slide 1-3 Detector-12 DC Control Panel

Other optional DC Control components:

All 12 lamps

Engine Oil Temperature gauge.

Tachometer.

Turbocharger Pyrometer.

Engine speed adjust pot.

Emergency Stop switch.



Detector Front Panel Quiz

Complete the following quiz to check on your knowledge of the Detector Control front panelcomponents.

1. What component comes standard on ALL Detector Controls?A. S13B. CB12C. CB21D. M21

2. What component does not come as part of the Meter Kit?A. M21B. M22C. R21D. S21

3. What component tracks engine operation for oil changes?A. M11B. M12C. M13D. M14

4. Which switch has a lamp in it to indicate resetting of the control is needed?A. S11B. S12C. S13D. S21

5. Which optional component indicates engine exhaust temperature?A. M12B. M13C. M15D. M17

6. Which component has either seven or twelve lamps installed?A. A11B. A12C. A13D. A14



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Lesson: Cummins/Onan DiagramsIntegrated Generator Set Controls


Lesson: Cummins/Onan Diagrams

This lesson presents an overview of the different types of diagrams used with Cummins/Onanand Cummins Power Generation products.

Objectives


• Identify a diagram by its number and designation.

• List four different types of Cummins/Onan diagrams.

• Read and interpret Cummins/Onan wire markings.

• Describe when you would use each type of diagram.

• Select and use all types of Cummins/Onan diagrams.

Cummins is a registered trademark of Cummins, Inc.Onan is a registered trademark of Onan Corporation.

Lesson: Cummins/Onan Diagrams Integrated Generator Set Controls


Block Diagram

VOLTAGEREGULATOR

(VR21)

AUXILIARY TERMINALBOARD

MAIN STATOR

MAIN ROTOR

MAIN STATOR

EXCITER

EXCITER

EXCITERSTATOR

ROTOR

STATOR

ROTATING DIODES

Slide 2-1 Block diagram

Block diagrams are used to show an overall view of a system or major component. Blockdiagrams show the system or component in a much larger scale than is used in any otherCummins/Onan diagram.

To use these other diagrams effectively you must learn how to read the diagrams. The purpose ofeach of these diagrams is different, and they should not be substituted for each other. You mustuse the proper diagrams for your specific equipment to be totally accurate.

Interconnection DiagramTells technicians or installers how to install and connect components.

Wiring DiagramUsed to put the equipment together correctly.

Schematic DiagramUsed to design the functions of the equipment and sell equipment to the customer.

Reconnection DiagramShows where the alternator output wires and the sensing wires connect for each generatorset output voltage.



Interconnection Diagram

Slide 2-2 Interconnection Diagram

Interconnection diagrams are used with kits or when connecting equipment to create a system.One of the most common installation diagrams is 630-1345.Wiring diagrams are designed to beused when you have to replace a part or a wiring harness in a piece of equipment in the field.When connecting a transfer switch and generator set together in the field you would use aninterconnection diagram.

Interconnection Diagrams show:

Point-to-point wiring connections between components.

Relative position of all connections on the parts inside the equipment.

Notes and tabulations which are important for the installation to be successful.

Tabulations showing size, length and type of wire to be used.



Wiring Diagram

Slide 2-3 Wiring Diagram

Wiring diagrams are used when building equipment at the factory, and when tracing wiring inthe field. These diagrams show where each end of the wires connect. When replacing a wiringharness in the field, you would use a wiring diagram.

Wiring Diagrams show:

Inside view of all panels and control boxes.

Point-to-point wiring connections.

Relative position of all connections on the parts inside the equipment.

Exploded views of sheet metal parts.

Optional parts and wiring as dashed lines.



CPG Wire Markings

!"

! "

TB21–23

TB21–23

Slide 2-4 Wire Markings on a Cummins/Onan Wiring Diagram

All wires used in Cummins / Onan generator sets are marked on both ends with where the wireconnects.

The marking closest to the end of the wire shows where that end connects.

The marking farthest away from the end of the wire shows where the other endconnects.

When connecting wires, use only the marking closest to the end in your hand. Do not payattention to the other marking—unless the wire is in the harness backwards.

If the markings are worn off one end of the wires, by reading the markings on the wireyou can find the other end of the correct wire to use .



Wire Marking Worksheet

Using the wiring diagram shown on the previous page, fill in the following information: What isprinted on the wire ends shown in slide 2-4 on the previous page?

#$%&'%()

(%

&''*)

(%



Schematic Diagram

Slide 2-5 Schematic Diagram (Detector AC Control without meters)

This diagram is a schematic of the AC Control for a Cummins/Onan generator set which doesnot have the optional meter package installed on the Detector Control.

Component Identification:

• CB21 Field Breaker

• G21 AC Generator

• VR21 AVR

• TB21 AC Control terminal board



Operational Schematic Diagram

X (+)

XX (–)

L1

L3

L2

ReferenceVoltage In

Regulator

Excitation Out

Exciter

ExciterRotor

Main Rotor

MainStator

L0

CB21

(–) (+)

Stator

K1K2

Drive Voltage In

Rotating Diodes

Slide 2-6 Schematic Diagram of generator operation

Schematic diagrams show the operation of a an item of equipment or a system. Schematicdiagrams are designed to be used when you have to troubleshoot a piece of equipment in thefield. Normally schematic diagrams will show the input and output pin numbers for signaltracing.

Schematic Diagrams show:

Sequence of operation of the circuit or component.

Input and Output wiring connections.

All needed connections on the parts inside the equipment.

Selected parts on circuit boards.

Signal flow of circuit components.



Reconnection Diagram

+,

-

-

-

-

+-,

+,

"+.,

.

-

-

-

-

-

// 00011 22222

// 00011 22222

2

03

3.3

33

33410

-25

..0-

-2.

11

01

111

-

6-0

7

7

7

7

..0-

./

183

.33

Slide 2-7 Reconnection Diagram

Reconnection diagrams show how to connect the alternator output wires, current transformersecondary windings and sensing leads. Reconnection diagrams are designed to be used when youhave to check or change the output voltage of a generator set in the field.

Reconnection Diagrams show:

Whether the generator is reconnectable, what output voltages and frequencies can beused, and how the output wires are marked.

Current Transformer secondary connections.

Schematic diagram of generator wiring connections (Wye, Delta).

Wiring diagram of output connections from the reconnection studs to the auxiliaryterminal block (with or without transformer connections).

TB21 connections with different control inputs.

Where to connect voltage reducing transformers used on non-reconnectible and mediumvoltage generator sets.



Cummins/Onan Diagram Quiz

Work with the other people in your work group to complete this worksheet.

1. Which diagram is used when replacing a DC control wiring harness?

2. Which diagram shows the technician how to wire the current transformer secondaryterminals?

3. Which diagram would be used to check inputs and outputs of a circuit board?

4. Which diagram would show the most general view of a system?

5. Which page of a 2-page circuit board diagram shows the parts on the board?

6. Which page of a 2-page circuit board diagram shows the circuits on the board?

7. Where would a technician find the nomenclature of a part used on a diagram?

8. What wiring diagrams show the size of wire to be used when connecting several components?

9. In the slide shown on page 2-3, what polarity of voltage is used as a remote start signal withthe Detector-12 Control?

10. What type of diagram would be used with a reconnection diagram to find which terminals ona voltage regulator are used for reference voltage input and excitation voltage output?

Lesson: DC Control Inputs and OutputsIntegrated Generator Set Controls


Lesson: DC Control Inputs and Outputs

This lesson presents an overview of the DC Control Engine Monitor Board (ECM) inputs,outputs, fuses and jumpers.

Objectives


• Identify the connectors on the A11 Engine Control Monitor (ECM) board.

• Identify the functions of the A11 ECM fuses.

• Identify the Inputs and Outputs of the A11 ECM board.

• Identify the most important components on the A11 ECM.

• State expected polarity of A11 ECM input and output signals.

• State when a specific signal is expected as an input or output of the A11 ECM.

• Identify A11 ECM Jumpers.


Lesson: DC Control Inputs and Outputs Integrated Generator Set Controls


Older ECM Connectors

Slide 3-1 Older A11 ECM Connections and Fuses

Connectors

TB1 Customer Inputs and OutputsTB2 Customer Inputs and OutputsP1 Start Disconnect Inputs, Ground Input, engine sender InputsP2 Engine Warning and Shutdown Inputs P3 Connections to A12 Lamp assemblyP4 Connections to front panel components

Fuses

F1 20 Amps for Starter signalF2 20 Amps for Switched B+F3 15 Amps for Battery Charger or Transfer SwitchF4 5 Amps for A11 operationF5 5 amps for engine gauges



ÉÉÉÉÉÉ

ÇÇÇÇÇÇÇÇÇÇÇÇ

ÉÉÉÉ

ÉÉÉÉ

K2 K3K7 K12

K6 K10

K1

K14

ÉÉÉÉÉÉÉÉÉ

ÉÉÉÉÉÉÉÉÉ ÉÉ

ÉÉÉÉÉÉ

Main Components

VR1

U1

Slide 3-2 A11 ECM Components

Important Relays

K1 Oil Pressure Time Delay relay.K2 Switched B+ relay.K3 Starter relay.K6 Latching Fault relay.K7 A11 Run relay.K10 AC Starter Disconnect relay.K12 Cycle Crank relay.K14 DC Starter Disconnect relay.

Other Components

VR1 DC Supply Surge Suppressor.U1 Cycle Crank Timer chip



B

B

W6

B

W7

W2A

C

D

W1A

C

Older ECM Jumpers

AW3W4A

A

W9

A

W8

W5

B

Slide 3-3 A11 ECM Jumpers

Moveable Jumpers

W1 Customer Fault 2 selection jumper.W2 Customer Fault 1 selection jumper.

“A” = Non-Timed Warning“B” = Non-Timed Shutdown“C” = Timed Warning“D” = Timed Shutdown

W6 “A” sets Pre-High Coolant Temperature to Alarm modeW7 “A” sets Pre-Low Oil Pressure to Alarm mode.W8 Customer Fault 2 selection jumper.W9 Customer Fault 1 selection jumper.

“A” = Warning when running or stopped.“B” = W1 & W2 are used to select Warning or Shutdown.

Solderable Jumpers

W3 / W4 Factory set in “B” position. Move to “A” position for Ground to start input signal.

W5 Factory set in “A” position for cycle cranking.



New ECM with LEDs

Slide 3-4 NEW Detector Board showing LED, new jumpoer, and TB3 placement

LEDs

DS1 B+ connected GreenDS2 Run mode GreenDS3 Start Command GreenDS4 Crank output GreenDS5 DC start disconnect GreenDS6 AC start disconnect GreenDS7 LOP/HET enabled GreenDS8 Reverse battery polarity RedDS9 Remote/Emergency stop Red

Other functional Additions Include:

SW OFF FLASHER Jumper (W10)Customer request for a jumper inserted in the sw off flasher circuit to have three options for the light;disabled, flashing, or constant.

ADD THREE TERMINAL BLOCK–START/STOP/REMOTE SWFor diagnostic purposes. P3 and P4 connectors have been a source of warranty claims due to poorcontact continuity. Connector cannot be changed in field without changing mating connector. Terminalblock allows alternative connection to functions as a field test feature, or could be hard wiring if desired.



Inputs & Outputs

Slide 3-5 A11 ECM Inputs and Outputs — Run and Remote modes

TB1 Inputs:

B+ Unfused Battery B+ input.

RMT B+ input from transfer switch for automatic operation.This is the only terminal not used for both operating modes.

TB1 Outputs:

B+ Fused by F3 for B+ output to Transfer Switch or Battery Charger.

Ground Ground return for Battery Charger.

Starter Fused by F1 for B+ output to the starter solenoid.

SW B+ Fused by F2 for Switched B+ output for “RUN” circuit.Governor, Ignition and Fuel systems



Inputs & Outputs

8 7 6 5 4 3 2 1

Slide 3-6 A11 ECM Required Inputs

P1 / J1 Required Input signal:

Main GROUND input from ground stud in control box.

Run circuit Input signals:

90-120 VAC input for AC Starter Disconnect signal.

B+ input from for DC Starter Disconnect signal.

This can come from several places:Battery Charging Alternator enters P1-3 (300-2809 — 300-2812)DKA-Series gensets enters P1-5 from Overspeed Module (300-4294 —300-4297)



Inputs & Outputs

8 7 6 5 4 3 2 1 6 5 4 3 2 1

Slide 3-7 A11 ECM Warning and Shutdown Inputs

P2 / J2 Input signals (Alarms and shutdowns):

Low Engine Temperature (less than 70° F.)

Low Oil Pressure shutdown.

High Engine Temperature shutdown.

Pre-Low Oil Pressure Alarm.

Pre-High Engine Temperature Alarm.

Overspeed shutdown.

TB1 shutdown Input

Overspeed input from PMG Frequency Detection Module.



Inputs & Outputs

8 7 6 5 4 3 2 1 6 5 4 3 2 1

P3

Slide 3-8 A11 ECM Outputs to A12 Lamps

P3 / J3 Output signals for Detector-7 Controls:

B+ to all lights on A12 assembly. Fused by F4.

Ground output for RUN lamp.

Ground output for Overcrank shutdown lamp.

Ground output for Overspeed shutdown lamp.

Ground output for High Engine Temperature shutdown lamp.

Ground output for Low Oil Pressure shutdown lamp.

Ground output for Pre-High Engine Temperature Alarm lamp.

Ground output for Pre-Low Oil Pressure Alarm lamp.



Inputs & Outputs

8 7 6 5 4 3 2 1 6 5 4 3 2 1

Slide 3-9 A11 ECM Front Panel Inputs and Outputs

P4 / J4 Major Input and Output signals:

Switched B+ output from F5 for engine gauges.

B+ input to K7 from S12 terminal 2.

B+ output to S12 terminal 3 for RUN operation.

B+ output to S12 terminal 1 from TB1-6 and F3 for automatic operation.



Inputs & Outputs

8 7 6 5 4 3 2 1 6 5 4 3 2 1

Slide 3-10 A11 ECM Inputs at TB2

TB2 Input signals: All are Ground potential.

FLT2 — latches FLT2 relay.

FLT1 — latches FLT1 relay.

Lamp Test / Fault Reset from paralleling system.

Low Day Tank level.

Emergency Stop shutdown.



1 2 3 4 5 6 7 8 9 10 11 1412 13 15 1616

Inputs & Outputs

8 7 6 5 4 3 2 1 6 5 4 3 2 1

Slide 3-11 ECM Annunciator Outputs

TB2 Output signals (Annunciation): All are Ground potential.

FLT2

FLT1

Overcrank

Overspeed.

High Engine Temperature shutdown

Low Oil Pressure shutdown

Pre-High Engine Temperature Alarm

Pre-Low Oil Pressure Alarm

Switch Off (Not in Auto)

Low Engine Temperature Alarm

Low Day Tank level



A11 ECM Connection Quiz

Select the best answer for each question from the choices given.

1. Where does the ground signal enter the A11 ECM?

A. P1-1B. P1-4C. P1-6D. P1-8

2. Where does the Battery B+ signal enter the A11 ECM?

A. TB1-7B. TB1-8C. TB1-9D. TB1-10

3. Where does the Battery signal leave the A11 ECM for use as a remote start signal by the transfer switch?

A. TB1-7B. TB1-8C. TB1-9D. TB1-10

4. Where does the Switched B+ signal leave the A11 ECM for the Oil Pressure Gauge?

A. P4-5B. P4-6C. P4-8D. P4-9

5. Which fuse on the A11 ECM board could be bad if the A12 lamps do not light when S11 is moved to the Lamp Test/Reset position?

A. F2B. F3C. F4D. F5

6. Which fuse being bad would cause the EFC Governor not to operate?

A. F2B. F3C. F4D. F5



7. Where does the Low Oil Pressure shutdown enter and leave the A11 ECM?

A. P2-2 / TB2-3B. P2-3 / TB2-6C. P2-4 / TB2-9D. P2-5 / TB2-12

8. Where can an alternate Overspeed signal enter the A11 ECM?

A. TB1-1B. TB1-2C. TB1-3D. TB1-4

9. Where can you check for an output that is present only when the AC Start Disconnect is present?

A. TB1-1B. TB1-2C. TB1-3D. TB1-4

10. Where could the customer connect a Day Tank Rupture Basin contact so the genset would shut down if the contacts closed?

A. TB2-1B. TB2-2C. TB2-4D. TB2-5

11. Where could a remote reset signal be connected to the A11 ECM to reset Warnings?

A. TB2-1B. TB2-2C. TB2-4D. TB2-5

12. What relay latches whenever a shutdown condition input is present?

A. K1B. K2C. K6D. K7



13. What relay allows the ECM to monitor the oil Pressure and Coolant Temperature?

A. K1B. K2C. K6D. K7

14. What maximum value of signal is expected as an AC Starter disconnect?

A. 90 VACB. 100 VACC. 110 VACD. 120 VAC

15. What signal is present at TB1-3 or P4-1 when the AC Starter Disconnect is connectedto the ECM?

A. 120 VACB. GroundC. Switched B+D. B+

16. What time delay is selected or not selected with jumpers W1 and W2?

A. Customer FLT1 & FLT2B. Cycle Crank or Continuous CrankC. Oil Pressure TDD. High Engine Temp. TD

17. What position does W2 have to be in for FLT1 to be a non-timed shutdown?

A. AB. BC. CD. D

18. What A11 jumper can select Pre-Low Oil Pressure as a shutdown instead of a warning?

A. W3B. W4C. W6D. W7



19. Which jumper allows the customer to have continuous cranking instead of cycle cranking?

A. W3B. W4C. W5D. W6

20. What remote start input is expected on a 350DFCC ECM with factory settings?

A. GroundB. +12 VoltsC. +24 VoltsD. 120 VAC

Lesson: Troubleshooting the DC ControlIntegrated Generator Set Controls


Troubleshooting the DC Control

This lesson presents an overview of troubleshooting the Detector Control Engine ControlMonitor (ECM) board.

Objectives


• Identify input and output signals and their polarity in a static state.

• Identify input and output signals and their polarity when the ECM is operated from the frontpanel with S12 in the “RUN” position.

• Identify input and output signals and their polarity when the ECM is operated from a remotedevice with S12 in the “REMOTE” position.

• Describe the sequence of operation inside the Detector Control.

• Identify the fuses needed to operate the genset in each operating mode.


Lesson: Troubleshooting the DC Control Integrated Generator Set Controls


Old Detector ECM – 300-2812

Slide 4-1 Older Detector ECM – 300-2812 and its replacements

Originally designed in 2-Light and 12-Light versions for 12 Volt and 24 Volt systems.

Early boards had glass cartridge fuses, later boards had automotive-type fuses.

VR1 was a reverse polarity battery protection for the board circuits. Early VR1 was a Zenerdiode, later changed to an MOV.

Early boards had black relays for K2 and K3 with removable covers. Later versions had sealed,white relays for K2 and K3.



New Detector ECM – 300-4692

Slide 4-2 New Detector ECM – 300-4296

The latest Detector ECM has nine LEDs which indicate board operation.

DS1 B+ Input GreenDS2 Run B+ GreenDS3 Start Crank GreenDS4 Crank Output GreenDS5 DC Start Disconnect GreenDS6 AC Start Disconnect GreenDS7 LOP / HET Enable GreenDS8 Reverse Battery RedDS9 Remote Shutdown Red

There is a separate terminal Board (TB3) which has three terminals for an input to provide thefollowing functions:

TB3-1 Remote Start B+ Input TB3-2 Lamp Test / Reset Ground Input TB3-3 Manual Run B+ Input



Troubleshooting Hints

Questions to ask before and during troubleshooting:

What does the control do correctly?

What does the control not do?

Where should there be input signals?What type of voltage are they? AC / DCWhat level of voltage are they?

Where should there be output signals?What type of voltage are they? AC / DCWhat level of voltage are they?

Suggested DC Control Troubleshooting Sequence

1. Gather Information.

A. Lights / Switches

What alarm or Shutdown lights are lit? Where are the switches positioned? Is there a re-mote Emergency Stop switch? These will give you an idea of where to start your trouble-shooting efforts.

B. People.

What was happening just before this problem occurred? Were suspicious sounds head orsmoke seen in the area of the genset? Was someone near the genset who normally doesnot come into the area? Who had access to the set?

C. Visual Inspection.

With the genset stopped check genset fluids, battery electrolyte and voltage, generatorand load connections, circuit breaker connections and handle position, and connectionsinside the generator set control box. Check fuses on the ECM and switch positions on thefront of the genset control box.

D. Operational Check.

Attempt to start the set and verify the complaint on your work order. Listen to the enginesounds when starting and after starter disconnect occurs. With the genset running (at idleif appropriate) check oil pressure, coolant temperature, engine and generator sounds andcooling air.



E. Other Sources Of Information.

What entries are in the maintenance log for the set? What was the last part replaced —does that part have any connection to the present problem? Check the last repair or kitinstallation to make sure the set was left in operational condition.

2. Analyze The Information (Think!)

A. Use Your Knowledge Of The System(s).

Use your previous repair and troubleshooting experiences to think of some possiblecauses for this problem.

B. Troubleshooting Charts.

Look at the troubleshooting charts in the Operator’s Manual and Service Manual to seewhat checks are recommended by the factory for this problem.

Remember, many people worked to develop the troubleshooting charts in the manuals,and their experiences might help you repair this set.

C. Decide On Tests To Perform.

Using the troubleshooting charts, decide on what tests to perform and what you shouldsee if the results of these tests are good or bad.

Perform the tests and write down what you found from the tests. Writing down the resultswill help you remember what you tested, when you tested it, and the results of the test.

D. Common Point Analysis.

If several operations or circuits are affected, look for only those things that affect both ofthe operations or circuits.

If the genset cranks but does not start, and the electronic governor actuator does not moveduring cranking, check the engine gauges to see if A11 K2 is working.

E. Use Wiring Diagrams.

If you cannot find the answer to the problem in the Operator’s Manual or the ServiceManual, you will have to go to the prints for the genset and the control. It may help youto refer to the sequence of operation of the control in the Service Manual while you lookat the prints.

Again, write down what you want to check and the results of the check. If you find youare checking the same point for the third time, you might be looking for the wrong thing.



3. Perform Tests To Isolate Actual Cause Of Problem From Possible Causes Of Problem.

A. Voltage Checks.

Check for proper input and output signals at the ECM terminal blocks and connectors.Check on schematic and wiring diagram for location and estimate desired signal.

B. Jumper Lead Checks.

Use a jumper lead to connect B+ or Gnd to one end of a component like a relay to see ifyou can force the component to operate.

C. Continuity Checks.

Check the quality of the connection through a component or connector with an ohmme-ter.

D. Substitution.

If you cannot bypass surrounding components or wiring, temporarily replace the sus-pected component with a known good component. If the substitution does not change theoperation, replace the original component before going on to the next step.

If you change more than one variable in a circuit at a time, you may not know whichchange made the system operate properly.

5. Retest.

A. Assures Problem Is Fixed.

Check the genset to make sure the reported problem is fixed.

B. Assures No Additional Problems Exist Or Have Been Caused During Repairs.

Check all operations of the genset to make sure that something has not failed during thetesting and repair process.

C. Assures System Is Operational.

Make sure all parts of the ECM system operate properly.



ECM Static State Checks

B+

Unfused Battery B+ enters the ECM at TB1-9.

If Fuse F3 is good, Battery B+ will be available at TB1-7 for accessories whenever the batteries are connected.

DS1 will be lit if the ground wire is connected.

DS8 will be lit if the B+ and ground wires are connected backward.

Ground

The main ground enters the ECM at P1-6 from the ground stud inside the ECM cabinet.

The main ground leaves the ECM for a transfer switch or other remote battery charger at TB1-5



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Slide 4-3 ECM Static State Checks

DS1 B+ Connected DS6 AC Start DisconnectDS2 Run Mode DS7 LOP/HET EnabledDS3 Start Command DS8 Reverse Battery PolarityDS4 Crank Output DS9 Remote/Emergency StopDS5 DC Start Disconnect



ECM Manual Operation Mode Checks

B+Battery B+ enters the ECM at TB1-9.If Fuse F3 is good, Battery B+ will be available at TB1-7 for accessories whenever the batteries are connected.

GroundThe main ground enters the ECM at P1-6 from the ground stud inside the ECM cabinet.The main ground leaves the ECM for a transfer switch or other remote battery charger at TB1-5

Start & Run Sequence

1. Battery B+ applied to TB1-9 connects through F4 to S12 “RUN” through P4-6, and to K7 NO contacts through K6 NC contacts.

2. When S12 is moved to “RUN” position, Battery B+ is applied to right side of K7 coil and K7 energizes. K7 NO contacts close and K2 and K3 coils energize.

3. K3 NO contacts close and apply Battery B+ through F1 to the starter solenoid to crank the engine.

4. K2 NO contacts close and apply Battery B+ through: F2 to engine terminal 26 to energize the fuel, ignition, and governor systems. F5 to P4-9 to provide power to the engine gauges and the hour meter.

5. If the engine cranks for 15 seconds without starting, K12 will be energized and the K12 NC contacts will open to remove ground from the K3 coil. This allows the starter to rest for 15 seconds.

6. Once the engine starts to accelerate and the DC alternator output reaches 18 Volts, theDC Starter Disconnect relay, K14, energizes. The K14 NO contacts close, opening the ground path for K3 and the starter is disengaged.

7. Once the generator set reaches approximately 850 RPM, the AC Starter Disconnect signal from TB21-21 and TB21-32 reaches approximately 100 Volts. This signal energizes relay K10. The K10 NO contacts close supplying a ground to the RUN lamp on the front panel of the control through P3-5 and to the annunciator Run lamp through TB1-3.



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Slide 4-4 ECM Manual Operation Mode – Crank & Start

A11 K7 energizes when S12 is placed into the RUN position.

Either A11 K10 or A11 K14 energizing will remove the groundfrom A11 K3 and remove the starter signal from A11 TB1-8.

A11 K10 NO contacts to A11 TB1-3 will close when the AC startdisconnect signal is received at A11 P1-1 and -2.



ECM Automatic Operation Mode Checks

B+Battery B+ enters the ECM at TB1-9 and passes through F3 to the Remote Start Contacts in the transfer switch.



1. Battery B+ applied to TB1-9 through F4 to K7 NO contacts through K6 NC contacts.

2. For automatic operation, S12 must be left in the “Remote” position. This connects P4-5 to P4-7 and the right side of the K7 coil. When the Remote Start Contacts close, B+ is applied to TB1-6, P4-5, P4-7, and the right side of K7 coil energizing K7. K7 NO contacts close and K2 and K3 coils energize.

3. K3 NO contacts close and apply Battery B+ through F1 to the starter solenoid to crank the engine.

4. K2 NO contacts close and apply Battery B+ through: F2 to engine terminal 26 to energize the fuel, ignition, and governor systems. F5 to P4-9 to provide power to the engine gauges and the hour meter.

5. If the engine cranks for 15 seconds without starting, K12 will be energized and the K12 NC contacts will open to remove ground from the K3 coil. This allows the starter to rest for 15 seconds.

6. Once the engine starts to accelerate and the DC alternator output reaches 18 Volts, theDC Starter Disconnect relay, K14, energizes. The K14 NO contacts close, opening the ground path for K3 and the starter is disengaged.

7. Once the generator set reaches approximately 850 RPM, the AC Starter Disconnect signal from TB21-21 and TB21-32 reaches approximately 100 Volts. This signal energizes relay K10. The K10 NO contacts close supplying a ground to the RUN lamp on the front panel of the control through P3-5 and to the annunciator Run lamp through TB1-3.



ECM Starter Disconnect Operation



Starter Disconnect Sequence

The DC Starter Disconnect signal comes from the DC alternator. When this voltage reaches approximately 18 VDC (24 V systems), K14 energizes. The K14 NC contactsopen and remove ground from K3 to de-energize K3.

The AC Starter Disconnect signal comes from the main alternator stator output voltage connections at TB21-21 and TB21-32. When this voltage reaches approximately 85 VAC, K10 energizes. The K10 NC contacts open to remove groundfrom K3 to de-energize K3. The NO contacts close and apply a ground to TB1-3 to light the “Generator Running” lamp on the annunciator.

If both DC and AC Starter Disconnect signals are present, the local run lamp on the front of the control box will light.



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Slide 4-5 ECM Automatic Operation Mode – Remote Start Signal Input

A11 TB1 Terminal 7 feeds Battery B+ to a remote start contact.When the remote start contact closes, Battery B+ is fed to the Re-mote terminal of S12.

With S12 in the Remote position, A11 K7 energizes when the re-mote start contacts close. Operation of the ECM is as above.



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Slide 4-6 ECM Automatic Operation Mode – DC Starter Disconnect

A11 K7 energizes when the remote start contacts close.





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Slide 4-7 ECM Automatic Operation Mode – AC Starter Disconnect

A11 K7 energizes when the remote start contacts close.





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Slide 4-8 ECM Diagram with Shutdown Fault

When a Shutdown input is received by the A11 ECM, the K6 relay is moved to the “set” positionand mechanically latched into that position.

This opens the K6 NC contacts leading to the K7 NO contacts and K2 and K3 deenergize.

The K6 NO contacts close placing Battery B+ voltage onto A11 TB1 terminal 4.

The G1 and G2 alternator outputs decrease below hold-in level so K10 and K14 will deenergize.



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Slide 4-9 ECM Overall Operation Diagram



ECM Overall Operation




1. Battery B+ applied to TB1-9 through F4 to K7 NO contacts through K6 NC contacts.

2. When K7 energizes, its NO contacts energize K2 (Switched B+) and K3 (Cranking).

3. K3 sends B+ through F1 to the starter to crank the engine.

4. K2 sends Switched B+ through F2 to engine terminal 26 for the engine fuel, ignition and governor systems, and through F5 to the engine gauges and meters.

5. Once the engine starts to run on its own, one of the Starter Disconnect signals will de-energize K3 to disengage the starter from the flywheel.

The DC Starter Disconnect signal comes from the DC alternator. When this voltage reaches approximately 18 VDC (24 V systems), K14 energizes. The K14 NC contactsopen and remove ground from K3 to de-energize K3.

The AC Starter Disconnect signal comes from the main alternator stator output voltage connections at TB21-21 and TB21-32. When this voltage reaches approximately 85 VAC, K10 energizes. The K10 NC contacts open to remove groundfrom K3 to de-energize K3. The NO contacts close and apply a ground to TB1-3 to light the “Generator Running” lamp on the annunciator.

If both DC and AC Starter Disconnect signals are present, the local run lamp on the front of the control box will light.

6. When B+ is removed from the K7 coil, or the K6 NC contacts open because of a shutdown signal, the K2 relay will de-energize. When the K2 NO contacts open, Switched B+ will be removed from engine terminal 26 and the engine will stop.



DC Control Troubleshooting Quiz

1. The Lamp Test switch does not light the A12 lamps. What could you check to find the problem?

2. The generator set will start from the transfer switch, but not with S12 in the “RUN” position. What could you check to find the problem?

3. The generator set will operate with S12 in the “RUN” position but not in “REMOTE.” What could you check to find the problem?

4. The generator set starts and runs OK, but the “RUN” lamp on the control box does not light. What could you check to find the problem?

5. The generator set does not crank at all. What could you check to find the problem?

6. The generator set cranks but will not start and run. What could you check to find the problem?

7. Where would you check to verify the AC Starter Disconnect is available?

8. Where would you check to verify the genset was shut down on Emergency Stop after the Emergency Stop switch was pulled out.

9. Which fuse would you check if the genset does not crank when S12 is in the “RUN” position?

10. Which fuse would you check if the genset does not crank when S12 is in the “REMOTE” position?




Lesson: DC Control SimulatorIntegrated Generator Set Controls


The DC Control Simulator

In this lesson you will construct a Detector-12 Control together, test inputs and outputs, andpractice troubleshooting the Detector-12 Control.

Objectives


• Replace an ECM board in a Detector Control on a generator set.

• Replace a wiring harness in a Detector Control on a generator set.

• Identify input and output signals, and their polarity, associated with the ECM.

• Identify the position and function of ECM jumpers.

• Describe the sequence of operation of the ECM.

Onan is a registered trademark of Onan Corporation.

Lesson: DC Control Simulator Integrated Generator Set Controls


Detector Control Simulator

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F1 F2

F3

F4

TB2

TB1

P1

VR1

K2 K3K7

K6

K10

K1

Slide 5-1 Detector Control Simulator

Use the following prints in your 960-0505 Service Manual to complete this exercise:

• 612-6488 (pages 1 and 2)

• INT-0192 (Operational diagram of the 12-light ECM)

During this exercise, your team will be asked to go through the procedures necessary to replace afailed Detector-12 harness and a failed ECM board. These steps will help you prepare for thetime when you have to do these same tasks because of a failure in the control box.



Detector 12 ECM

1 2 3 4 5 6 7 8 9 10 11 1412 13 15 161

2

3

4

5

6

7

8

9

10

F

1

F

2

F3

F4

F5

TB2

TB1

P4

P

3

P2P1

VR1K2 K3

K7 K12

K6K10

K1

K14

U1 U3 U5

U2 U4

Slide 5-2 Detector-12 ECM

Connecting The ECM Board To The Harness

• Connect the wiring harness J3 to ECM P3.

• Connect the wiring harness J4 to ECM P4.

• According to the numbers printed on the wires, connect wiring harness leads to S11, S12,and DS11.

1. Refer to the Wiring Diagram portion of your prints for terminal locations.

What print clearly shows the appropriate switch numbers?

Wiring Diagram Number: Sheet of 2.

2. Note: Six of the wires in this harness will not be used in this simulator. Four of the sixare for meters. Normally the other two wires are not used and tied back into the harness.

What was the purpose of the other two wires?

A11J4-1 A11J4-2



Connecting The ECM Board To The Harness

What J1/P1 pin connects to the ground stud in the control box?

3. Connect the BROWN ground wire from the ground screw to the appropriate terminal inthe white plastic J1 connector shell, then connect J1 to P1.

Do not connect the wire directly to the P1 terminal on the ECM board.

4. The red lamp that is mounted on the terminal 26 bracket has been provided to indicatewhen the control would be sending a Switched B+ output signal to terminal 26. The en-gine fuel solenoid, the governor and ignition coil are connected to terminal 26 on thegenerator set.

Where is TERMINAL 26 usually located on a generator set?

To which terminals on the ECM should the wires from Terminal 26 and the red lamp beconnected?

Terminal 26

Other red lamp wire

5. Connect these two wires to the terminals on the ECM you indicated above.

6. Place S12 in the STOP position.

7. Connect the black lead from the power supply to the ground stud.

Where should the Positive power supply terminal connect on the ECM?

8. Connect the striped lead with the insulated terminal from the power supply to the unfusedB+ input terminal on TB1.




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F1 F2

F3

F4

TB2

TB1

P1

VR1

K2 K3K7

K6

K10

K1


Test for correct operation of the simulator.

9. Plug the power supply into your extension cord. With S12 in the STOP position, theSWITCH OFF lamp should be flashing.

10. Pressing S11 to LAMP TEST should illuminate all A12 lamps.

11. Pressing S11 to PANEL LAMP should illuminate DS11.

What terminal on A11 TB1 connects to the starter solenoid?

12. Connect your test lamp to the starter terminal on A11 TB1 and the ground stud. to moni-tor the voltage to the starter circuit.

13. Place your finger lightly on the cover of K3 and put S12 in the RUN position. You shouldhear and feel K3 click about every 15 seconds for about 75 seconds. You should also seethe test lamp alternately turn on and off at 15 second intervals.



What happens at the end of this 75 second period?

14. Use your test lamp to check the COMMON ALARM output on TB1.

Is the COMMON ALARM terminal on A11 TB1 a Ground or B+ output?

15. Reset the OVERCRANK fault by placing S12 in STOP and pressing S11 to RESET.

Why does the control fault out on OVERCRANK?

What input(s) are necessary to avoid faulting out on OVERCRANK?

Consult your wiring diagram to determine which pin number at J1 & P1 is for the DC StartDisconnect input.

16. Simulate the DC Start Disconnect by connecting the RED wire from the appropriate pinon J1 to the Switched B+ terminal on TB1.

Which terminal on TB1 is Switched B+?

TB1-

17. Connect one end of your simulated DC Start Disconnect wire to this terminal on TB1.

Which connector in J1 / P1 is the DC starter disconnect input?

J1 / P1

18. Remove J1 from P1 on the ECM. Place the other end of the simulated DC startdisconnect wire into the appropriate hole in the J1 connector and reconnect J1 to P1.

19. Place S12 in the RUN position while again feeling and listening for K3 to cycle. If youcorrectly connected the DC Start Disconnect signal, K3 should NOT cycle on and off as itdid before.

20. With the simulated DC start disconnect signal, the board should have immediately gonefrom the crank mode to the run mode.



Is the red lamp on the TERMINAL 26 bracket lit? Yes / No

Is the green Local RUN lamp lit? Yes / No

Why or why not?

(Hint: See K10 on sheet #2 of print 612-6488)

TB1-3 is output to a remote RUN lamp (usually on an annunciator).

Is there an output at TB1-3? Yes / No

What polarity?

Why?




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F1 F2

F3

F4

TB2

TB1

P1

VR1

K2 K3K7

K6

K10

K1


21. You are about to connect AC Start Disconnect at J1 & P1. Place S12 in the STOPposition.

What two J1/P1 pins are for AC Start Disconnect?

and

22. Remove J1 from P1 on the ECM. Install the pin connectors of the short AC power cordinto the AC start disconnect pins in J1 and reconnect J1 to P1 on the ECM.

23. Move the wire attached to the red lamp from TB1-5 to TB1-3 (remote RUN).

This will allow the red lamp to simulate the RUN lamp on an annunciator. It will stillhave Switched B+ on one side (T26) but the other signal will depend on the AC startdisconnect input to the ECM.

24. Please have your instructor check your work before proceeding.

_____________________________ Instructor’s okay




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F1 F2

F3

F4

TB2

TB1

P1

VR1

K2 K3K7

K6

K10

K1


25. Move S12 to the RUN position and then connect the short AC power cord to theextension cord.

Does the green Local RUN lamp light now? Yes / No

Why?


What polarity?

Why?

26. Remove the simulated DC Start Disconnect signal by disconnecting the RED wire fromTB1-10, but leave the AC Start Disconnect signal connected.



Does the green RUN lamp on DS12 remain on? Yes / No

Why?


What polarity?

Why?

What can you conclude about the relationship between the AC Start Disconnect Input and theRemote RUN Lamp?

What can you conclude about the relationship between the AC and DC Start Disconnect inputsand the Local RUN Lamp?

27. Disconnect the AC start Disconnect cord from the extension cord.

28. Move S12 to the STOP position and reconnect the RED (simulated DC start disconnectsignal) wire to A11 TB1-10.

29. Move the red lamp wire from TB1-3 back to TB1-5.




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F1 F2

F3

F4

TB2

TB1

P1

VR1

K2 K3K7

K6

K10

K1


ALARMS & FAULTS

What pin at J2/P2 is for Pre-LOP input?

30. Move S12 to the RUN position. After approximately ten seconds you will hear A11K1energize. This is the Oil Pressure Time Delay (OPTD) relay. After A11K1 energizes, theECM can sense oil pressure, water temperature, and timed customer fault (FLT) inputs.

31. Place the appropriate PRE-LOP input signal at the proper P2 pin.

Does the Pre-LOP lamp in the A12 lamp assembly light? Yes / No

Is there a time delay before anything happens? Yes / No

32. Do not reset the control yet.

What pin at J2/P2 is for LOP shutdown input?



33. Momentarily place the LOP Fault input at P2.

Does the LOP lamp in the A12 lamp assembly light> Yes / No

Is there a time delay before anything happens? Yes / No

What polarity is the Common Alarm output at A11 TB1-4?

Why is this output here now?

Did the RUN lamp at terminal 26 go out? Yes / No

Why or why not?

34. Reset the control and check at least one other alarm and fault input at P2.

35. Next you will check the customer fault inputs and outputs at TB2-1 through TB2-4.

What would you connect to these terminals?

What polarity of signal is required as an input for FLT2 and FLT1 to operate?

What polarity of signal is the output from FLT2 and FLT1 (TB2-2 or TB2-4)?

36. Reset any remaining alarms or faults. Place the proper input signal at TB2-1 and moveS12 to the RUN position.

Is there a time delay before FLT2 operates? Yes / No

Is FLT2 a Pre-Alarm or a Shutdown?

37. Reset the control. Place the proper input signal at TB2-3 and move S12 to the RUNposition

Is there a time delay before FLT1 operates? Yes / No



Is FLT2 a Pre-Alarm or a Shutdown?

What jumpers on the A11 ECM change FLT2 and FLT1 to Pre-Alarm or Shutdown?

FLT2

FLT1

Do these jumpers have control when the genset is not operating? Yes / No

38. On the new ECM (with the white A11K2 and A11K3 relays) some of the other jumpersare also moveable without using a soldering iron.

Which jumpers are moveable by hand?

What is the function of W6?

What is the function of W7?

39. Place W6 or W7 in position “B” and test the Pre-LOP or Pre-HET functions again.

What happened this time?

Why?

What is the function of W8 and W9?

40. Move S12 to the STOP position and reset the control.

41. Move W2 to the “B” position and W8 to the “A” position. With S12 in the REMOTEposition, place a ground signal on TB2-1

What happened?



Why?

When would this be useful?




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F1 F2

F3

F4

TB2

TB1

P1

VR1

K2 K3K7

K6

K10

K1


Disconnecting The Simulator42. Please connect all moveable jumpers to the positions shown below so the next class can

get the same training you did.

W1 ⇒ B W2 ⇒ D

W6 ⇒ A W7 ⇒ A

W8 ⇒ B W9 ⇒ B

43. Disconnect all wires except those listed below.

DO NOT disconnect the following leads:– The lead from the ground stud to the door.– Ground wire on door hinge which was connected to S11-2.– The two wires at the Terminal 26 screw.– Harness between A12 lamp assembly and P3.– A11P4 and the J4 harness to the door.

44. Disconnect J1 from P1 and use the pin removal tool to carefully remove all wires fromJ1.



45. Do not use force to separate the pins from the J1 8-pin housing. If you need instructionon the use of the pin tool, please ask. It is very easy to destroy the pins.

46. If you destroy a pin, please ask your instructor for a replacement pin and crimp tool tomake the repair to the simulator.

47. Connect J1 to P1.

48. Place all of the following loose parts in the simulator:– Short AC Start Disconnect cord– AC extension cord– Power supply with leads wrapped up– Pin removal tool– All loose leads and jumper wires– Test Light– Screwdriver

49. Ask your Instructor to verify proper disassembly, and where the simulator is to be placedfor storage.

Lesson: The DC Control Auxiliary Relay BoardIntegrated Generator Set Controls


The DC Control Auxiliary Relay Board (ARB)

This lesson presents an overview of the operation and troubleshooting of the Auxiliary RelayBoard (ARB) used with the A11 ECM.

Objectives


• Identify input and output signals, and their polarity, associated with the Auxiliary RelayBoard.

• Identify the position of jumpers used with the K1, K2 and K3 relays when using the relay asa Run relay, Common Alarm relay, or an Isolated relay.

• Describe the sequence of operation of the K1, K2 or K3 relays when they are used as a Runrelay, Common Alarm relay and an Isolated relay.

• Identify input and output signals for the optional relays and terminal boards on the ARB.


Lesson: The DC Control Auxiliary Relay Board Integrated Generator Set Controls


K1 K2 K3

RUN RELAYMODULE(S)

JUMPERSJUMPERS

TB6, TB7 ANDRELAYS K4

THROUGH K15ARE OPTIONAL

J1, J2 WIREHARNESS PLUGCONNECTIONS

FROM A11

Slide 7-1 AUXILIARY RELAY BOARD (ARB)



Optional Auxiliary Relay Board (A28)

The following describes the design/functional criteria for the auxiliary relay board (ARB)with a Detector-7 or -12 Genset control. When provided, the board is mounted on the rearwall of the control box as shown in slide 1. There are two versions of the ARB; with andwithout the set of 12 Fault relays.

Terminal Blocks:

• TB1 – ARB TB1 and engine monitor TB1 are identically numbered and provide the sameremote control connection points. Note that additional terminals are provided for terminals5, 7, and 10 of ARB TB1.

• TB2 through TB5 – Connection points for relays K1 through K3. TB2 provides the N/Oand N/C connections (three form ‘C’ contacts for each relay). TB3 through TB5 provide thecommon connection points (TB3 for K1, TB4 for K2 and TB5 for K3).

• TB6 and TB7 – Connection points for fault relays K4 through K15. Three terminals areprovided for each relay, which are labeled COM, N/C, N/O.

Plug-In Relays (K1, K2, K3):

• The ARB can be equipped with up to three 3-pole, double-throw relays. These relays (K1,K2, K3) are field changeable plug-in relays for easy field addition and replacement.

• Each relay can be operated as a RUN Relay, COMMON ALARM Relay, or ISOLATEDCOIL Relay with the changing of a jumper.

The relay contact ratings are:

• 10 amps at 28 VDC or 120 VAC, 80% PF

• 6 amps at 240 VAC, 80% PF

• 3 amps at 480 VAC, 80% PF

Fault Relays (K4 through K15)

• These optional relay modules are used to operate a remote alarm annunciator that has anindependent power source. This allows the use of either AC or DC for alarm drives. Therelays are energized through the latching relays on the engine monitor and provided N/Oand N/C contacts for each external alarm connection.

• The 12 relays with form ‘C’ contacts are rated at 10 Amp, 120 VAC or 10 Amp. 30 VDC



K1 Relay Connections

Slide 7-2 Portion of ARB schematic diagram showing K1 circuits

Jumper settings for K1 Relay Operation

W1 W11 K1 Energizes when:

A B Genset cranks or runs.

A A Genset cranks or runs and an isolated ground is applied to TB3-5.

B B Genset has a shutdown fault.

B A Genset has a shutdown fault and an isolated ground is applied to TB3-5.

C B Isolated B+ is applied to TB3-1.

C A Isolated B+ is applied to TB3-1 and an isolated ground is applied to TB3-5.

W2 / W12 perform the same functions for K2W3 / W13 perform the same functions for K3

K1 is factory set as a “RUN” relay,K2 as a “Common Alarm” relay, andK3 as an “Isolated” relay.



Jumper Positions for Plug-In Relays:

Jumpers W1, W2 and W3 perform the same functions for their respective relays.

• W1 for relay K1, W2 for relay K2, and W3 for relay K3.

• These jumpers control how B+ is connected to the relay coil via TB3-1, TB4-1 or TB5-1.

These jumpers can be located in any of 3 positions (A, B, C) independently of each other.

• Jumper Position A (Run)

The associated relay operates as a Run relay, energizing when SW B+ is applied from theengine monitor.

• Jumper Position B (Common Alarm)

The associated relay operates as a Common Alarm relay. The relay energizes any time thereis an engine shutdown. This signal is provided from the engine.

• Jumper Position C (Isolated)

The associated relay operates as an Isolated relay. The relay coil is energized by a customerapplied B+ signal through the terminal block; TB3-1 for relay K1, TB4-1 for relay K2, andTB5-1 for relay K3.

Jumpers W11, W12, and W13 perform the same functions for their respective relays.

• W11 for relay K1, W12 for relay K2, and W13 for relay K3.

• These jumpers control how GND is connected to the relay coil via TB3-5, TB4-5 or TB5-5.

These jumpers can be located in two different positions (A, B) independently of each other.

• Jumper Position A

The relay operates isolated from the board. The customer provides the circuit completionthrough terminal block; TB3-5 for relay K1, TB4-5 for relay K2, and TB5-5 for relay K3.The customer can operate the relay with switched ground logic or use this relay in themiddle of more complex logic circuits if needed.

• Jumper Position B

The relays operate with the coils connected to ground through the board connections. Thecoil will require a B+ signal to energize with the jumper in this position.



Auxiliary Relay Board Quiz

Select the best answer for each question.

1. Which jumpers are used with the K2 relay?A. W1, W11B. W2, W12C. W3, W13D. W2, W22

2. Where would you place the W1 jumper to have the K1 relay operate when there is a shutdown?A. AB. BC. CD. D

3. Where would you place jumper W11 to use a ground input from a louver limit switch to light a lamp when the genset is running and the louvers are open?A. AB. BC. CD. D

4. When using K3 as an isolated relay, where do the coil wires connect to their signals?A. TB2B. TB3C. TB4D. TB5

5. TB1 on the ARB connects to ______ on the ECM.A. P1B. P2C. TB1D. TB2

6. TB6 on the ARB provides connection points for relaysA. LOP and LET.B. HET and OC.C. PRELOP and SW OFF.D. FLT1 and OS.

Lesson: AC Control Inputs and OutputsIntegrated Generator Set Controls


AC Control Inputs and Outputs

This lesson presents an overview of the input and output signals associated with the AC Controlsection of an Integrated generator set.

Objectives


• Identify integrated generator set AC Control components.

• Describe the sequence of operation of the integrated generator set AC Control.

• Identify and locate jumpers used on the different automatic voltage regulators (AVRs).

• Identify input and output signals for the different AVRs used with Integrated generator sets.

• Develop a troubleshooting aid showing input and output voltages from no-load to 100%load on the different AVRs used with Integrated gensets.


Lesson: AC Control Inputs and Outputs Integrated Generator Set Controls


AC Control Block Diagram

L1

L3

L2

L0

Slide 7-1 Block diagram of a typical AC Control

This diagram shows the two main types of hardware used in Cummins/Onan generator set ACControls.

The top (dashed) box contains all the hardware used in AC Controls which moves. These pieces are connected to the engine crankshaft with a flexible connection whichhelps prevent vibration caused by unbalance and alignment from affecting engineoperation.

The bottom box contains all the hardware used in AC Controls which is stationary. These pieces are either built into the stator housing or are in the Control Box.

The Voltage Regulator performs three separate functions:

• SENSING Determines if the input voltage is too low, just right, or too high.

• CONTROL Tells the Output section what to do to get the input voltage to the properlevel.

• OUTPUT Increases or decreases the current through the Exciter Stator to increase ordecrease the voltage input to the AVR.



AC Control Inputs & Outputs

X (+)

XX (–)

L1

L3

L2

Excitation

Exciter

ExciterRotor

Main Rotor

Main Stator

L0

(–) (+)

Stator

RotatingDiodes

AVR

! "

Slide 7-2 Each part in the AC Control System has an input (or inputs) and an output.

Part Name Input Output

• AVR Reference Voltage Excitation VoltageRegulator Drive Voltage

• Exciter Stator Excitation Voltage Magnetic Flux

• Exciter Rotor Magnetic Flux 3-Phase AC Voltage

• Rotating Diodes 3-Phase AC Voltage DC Voltage

• Main Rotor DC Voltage Magnetic Flux

• Main Stator Magnetic Flux 1-Phase AC or3-Phase AC Voltage



32

31

EXCITER ROTOR

MAIN STATOREXCITER

87

TB21

22

21

24

23

25

7

8

MAIN ROTOR

STATOR

ROTATING RECTIFIERS

Field CircuitBreaker CB21

VoltageTrimmer R21(NOTE 3)

1 2 3 4 5 6 7 8 9 10

VRAS-2AVR

Sensing and Drive Input Voltage

(VR21)

AC Start Disconnect

Slide 7-3 Onan 300-2880 AVR connection diagram

NOTES:

1. 7 and 8 are sensing leads wound into the generator as sensing leads.2. Unless the genset is used in a paralleling situation, there will be a jumper between

terminals 3 and 4 on the VR21 terminal block.3. There must be a fixed 5kΩ resistor between VR21-7 and VR21-8 when R21 is not used.4. This type of Voltage Regulator puts out 120 VAC from terminals 1 and 5 for the AC Start

Disconnect signal for the A11 DC Control board.5. All integrated genset AVRs send an AC Start Disconnect signal to the A11 ECM from

TB21-21 and TB21-32.



EXCITER ROTOR

MAIN STATOREXCITER

MAIN ROTOR

STATOR

ROTATING RECTIFIERS

32

31

876

SX-460VOLTAGE

SX-440 or

(VR21)TB21

22

21

24

23

256

7

8

K1 K2

AUXILIARY TERMINAL BOARD

P2 P3 P4 S2 S1 A2 A1 XX XX X 8 7 6 3 2 1

Field CircuitBreakerCB21


1 2 3 X XX P3 P2 K1 K2

265

AC Start Disconect

SensingDrive

REGULATOR

OUTPUT VOLTAGESENSING LEADS(NOTE 2)

Slide 7-4 Non-PMG Newage AVR connection diagram

NOTES:

1. Connect like numbered terminals on Auxiliary Terminal Board and AVR.2. See the appropriate reconnection diagram for placement of sensing leads 6, 7, and 8 on the

generator reconnection block.3. There must be a jumper between TB21–21 and VR21–1 when R21 is not used.4. Sensing wires 7 and 8 connect to terminals 2 and 3 on the SX-440 AVR.



ROTATINGEXCITERMAIN

MAINEXCITERN

S

PMG

PMG

VOLTAGEREGULATOR

MX-321

(VR21)

22

21

24

237

8

K1 K2

AUXILIARY TERMINAL BOARD

P2 P3 P4 S2 S1 A2 A1 XXXX X 8 7 6 3 2 1

2

1

8

7

6

X

XX

P4

P3

P2

K1

K2

E0

E1

8 7 6 –8 7 6 –

8

7

6

STATOR

ROTOR

RECTIFIERSROTOR

STATOR

ROTOR

STATOR

Field CircuitBreaker CB21


ISOLATION TRANSFORMER(NOTE 3)

INPUT OUTPUT

Over VoltageSensing Input

32

31

TB21

256

265

AC Start Disconnect

Sensing

Drive

Slide 7-5 PMG AVR connection diagram

NOTES:1. Connect like numbered terminals on auxiliary terminal board and voltage regulator.2. See the appropriate reconnection diagram for connecting sensing leads 6, 7, and 8.3. When the generator is connected for single-phase output, voltage regulator terminal 6 is not

connected to the isolation transformer but is jumpered to voltage regulator terminal 8.4. There must be a jumper between voltage regulator terminals 1 and 2 when voltage trimmer

R21 is not used.5. The resistor between terminals 26 and 32 of TB21 reduces the AC Start Disconnect signal

to 120 VAC maximum for the A11 ECM.



TB21 Connections

31

32

27

25

26

24

21

22

23

28

29

30

#$%& ' $ ()

%

* +,

* +-

* +.

* +/

* +0

1 '"

* * +*

* *'* + 2 %*

%

%

1

% * "

Slide 7-6 AC Control Inputs and Outputs — TB21 Connections

TB21 INTEGRATED GENSET INPUTS

When the generator is connected in a WYE or STAR configuration:Sensing leads 4 and 5 will be connected to the L0 or Neutral terminalSensing lead 6 will be connected to the midpoint of Phase C (L3)Sensing lead 7 will be connected to the midpoint of Phase A (L1)Sensing lead 8 will be connected to the midpoint of Phase B (L2)

TB21 INTEGRATED GENSET OUTPUTS

Reference Voltage for all Integrated Genset AVRs comes from TB21.

• Single-phase sensing AVRs (VRAS-2 and SX440) sense only phases A and B. TheirReference voltage comes from TB21-22 and TB21-23.

• The MX321 is a three-phase sensing AVR, and it gets its reference voltage from TB21terminals 22, 23 and 25.

• The AC start disconnect for the A11 ECM comes from TB21 terminals 21 (jumpered toterminal 22) and 32. The resistor between TB21-26 and -32 drops this voltage to a 90 to 120VAC range to prevent burning out A11 K10.



VRAS-2 Inputs / Outputs

S3

S1

S2

Volts/HzR-32

R-34

Volts

(sealed)

1 2 3 4 5 6 7 8 9 10

R21

34

45

-

-4

Slide 7-7 AC Control Inputs and Outputs — 300-2880 and 300-2977

The 300-2880 AVR is used with 20–350 kW Onan generators including all “A” sets and the “A–replacement” sets. The 300-2977 AVR is used with Onan generators from 325-750 kW.

300-2880 INPUTS

208 - 240 VAC input (common to Reference & Drive Voltages)

Drive Voltage return

Reference Voltage returnUnless installed in a paralleling system, terminals 3 & 4 will be jumpered together.

300-2880 OUTPUTS

120 VAC output for AC Start Disconnect120 VAC output for AC Start Disconnect

Excitation + (F1)Excitation – (F2)



SX-440 Inputs / Outputs

S2S1A2A1

87654321

60 C 50

ÉÉÉ

V/TRIM

DROOP

VOLTS

STABILITY UFRO

BLUECAP.

A B C

Optimum ResponseSelection Indicator

LED

UNDER 90 kW90 – 550 kW

OVER 550 kW

R21

34,54-/

Slide 7-8 AC Control Inputs and Outputs — SX440 (305-0624) or SX-460

The SX-440 AVR is used with Newage UC-type generators from 20-175 kW.

SX440 INPUTS

Reference Voltage (208–240 VAC)Reference Voltage (208–240 VAC)AVR Drive Voltage (208–240 VAC)AVR Drive Voltage (208–240 VAC)

S1 - S2 Cross-Current CT inputs for parallelingA1- A2 VAR/PF module inputs for paralleling to a utility

SX440 OUTPUTS

Excitation +Excitation –

NOTE: On all Newage AVRs the K1 and K2 terminals must be connected by a jumper or a circuit breaker to get excitation output from the AVR.



MX-321 Inputs / Outputs

3 2 1

DIP

C B A S1 S2A1 A2S1 S2

S1 S2E0 E1 B0 B1

K1 K2 P2 P3 P4 XX X 6 7 8 1 2

RMS

NO LINK 6P - 506P - 604P - 504P - 60

FREQUENCYSELECTION

UNDER FREQUENCY

DWELL

DROOPOVER/V EXC TRIP

STABILITY

V/TRIMU V W

FRAME 1, 2FRAME 3, 4, 5FRAME 6, 7

OPTIMUMRESPONSESELECTION

VOLTS

I/LIMIT

R21

34,54-3

Slide 7-9 AC Control Inputs and Outputs — MX321 (305-0623)

The MX-321 AVR is used with Newage HC-type generators from 200-1500 kW.

MX321 INPUTS

Reference Voltage (Phases A, B & C)

Regulator Drive Voltage (3-Phase input)

Overvoltage Sensing input

WS1-WS2 Cross-Current CT inputs for parallelingA1 - A2 VAR/PF module inputs for paralleling to a utility

MX321 OUTPUTS

Excitation +

Excitation –

B0 - B1 60 VDC pulse to shunt trip exciter breaker with trip feature.



AVR Load Chart

Do Not adjust this

S3

S1

S2

R-32

Volts

1 2 3 4 5 6 7 8 9 10

34

45

-

-4

potentiometer.

R-34

Slide 7-10 AVR Inputs and Outputs — VRAS-2

Using the generator set and load bank in the shop, complete the worksheet for this regulator.

Reference and Excitation

No Load

20%

40%

60%

80%

100%

PinsLoad

Drive Voltage Voltage

(+) (–)

Frequency



AVR Load Chart

S2S1A2A1

87654321

60 C 50

ÉÉÉÉÉÉ

V/TRIM

DROOP

VOLTS

STABILITY UFRO

BLUECAP.

A B C


LED

R21 Do Not Adjust potentiometers marked like this.

Slide 7-11 AVR Inputs and Outputs — SX-440 or SX-460


Reference Drive (Power) Excitation Frequency

No Load

20%

40%

60%

80%

100%

PinsLoad

Voltage Voltage Voltage

(+) (–)



3 2 1

DIP


S1 S2E0 E1 B0 B1

K1 K2 P2 P3 P4 XX X 6 7 8 1 2

NO LINK 6P - 506P - 604P - 504P - 60

FREQUENCYSELECTION

UNDER FREQUENCY

DWELL STABILITY

U V W

<90 kW90–550 kW>550 kW


VOLTS

R21

AVR Load Chart

Do Not Adjust potentiometers marked like this.

Slide 7-12 AVR Inputs and Outputs — MX-321Check PMG input at PMG connector, check sense voltage input at TB21


Reference Drive (Power) Excitation Frequency

No Load

20%

40%

60%

80%

100%

PinsLoad

Voltage Voltage Voltage

(+) (–)TB21–P PTB21–




Lesson: Automatic Voltage Regulator AdjustmentsIntegrated Generator Set Controls


Automatic Voltage Regulator Adjustments

This lesson presents an overview of adjusting the potentiometers and jumpers on the Onan andNewage Automatic Voltage Regulator (AVR) boards.

Objectives


• Identify Cummins/Onan Automatic Voltage Regulator (AVR) adjustments.

• Identify function of the adjustments on Cummins/Onan AVRs.

• Properly adjust a VRAS-2 AVR for a specific generator set.

• Properly adjust an SX-440 AVR for a specific generator set.

• Properly adjust an MX-321 AVR for a specific generator set.

Cummins is a registered trademark of Cummins, Inc.Onan is a registered trademark of Onan Corporation.

Lesson: Automatic Voltage Regulator Adjustments Integrated Generator Set Controls


VRAS-2 AVR Switches & Pots

S3

S1

S2

Volts/HzR-32

R-34

Volts

(sealed)

1 2 3 4 5 6 7 8 9 10

R21

S2

S1 or S3

Slide 8-1 AC Control Inputs and Outputs — 300-2880 and 300-2977

The 300-2880 AVR is used with 20–350 kW Onan generators including all “A” sets and the “A–replacement” sets; the 300-2977 AVR is used with 325–750 kW Onan generators.

300-2880 and 300-2977 Adjustments

R34 (Volts/Hz)Adjusts the rate at which the AVR will drop or increase output voltage after a load ap-plication or removal. This pot is adjusted on a computerized test bench, not in the field.

R32 (Volts)Adjusts the AVR to a specific Reference Voltage with a particular load. This pot is ad-justed after the front-panel voltage adjust pot (R21) is set to its midpoint.

Jumper between terminals 3 and 4is replaced with cross-current compensation circuit inparalleling installations.

S1, S2 and S3These are set according to the Service Manual for the specific generator set.



VRAS-2 Operating Modes

100

90

80

70

60

50

050 80 85 90 95 1000

Percent of operating RPM

95

Slide 8-2 Onan VRAS-2 Operating Modes

Torque MatchingMedium AVR (TMB)

Frequency SensitiveSoft AVR (TMA)

Non-Frequency SensitiveHard AVR (TMC)

By moving the S1, S2 and S3 switches on the Onan VRAS-2 AVRs (300-2880 and 300-2977)the technician can adjust the operation of the AVR for different types of loads.

The settings of S1, S2 and S3 are shown in the applicable Service Manual.

• The TMB setting is the factory standard for all Onan generator sets. This is a compromisesetting that makes the generator/regulator operate in a Semi-Frequency Sensitive mode. Asthe frequency drops from 100% to 90%, the voltage drops 1% for each 1% of frequencydrop. When the frequency goes below 90% of nominal, the rate of decrease of the voltagedoubles.

• The TMA setting is the Frequency-Sensitive mode of operation. The voltage drops off at 2%for each 1% decrease in the frequency. This setting sacrifices voltage to keep the frequencyas high as possible. This setting is recommended for heavy motor loads.

• The TMC setting is a Non-Frequency Sensitive setting that keeps the voltage constant untilthe frequency drops below 90% of nominal. Then the voltage drops at 2% for each 1% offrequency drop.



SX-440 AVR Jumpers & Pots

S2S1A2A1

1 2 3 X XX P4 P3 P2 K1 K2

60 C 50

V/TRIM

DROOP

VOLTS

STABILITY UFRO

A B C


LED

UNDER 90 kW90 – 550 kW

OVER 550 kW

R21

Reference Voltage jumpersset for AC reference input.

Reference Voltage jumpersset for DC reference input.

Slide 8-3 AC Control Inputs and Outputs — SX440 (305-0624)

SX440 Adjustments

StabilityAdjusts the amount of damping in the AVR regulation circuit. The higher the dampingeffect of this circuit, the slower the voltage changes.

VoltsAdjusts the AVR to a specific Reference Voltage with a particular load. This pot is ad-justed after the Optimum Response Selection jumper is connected for a specific alterna-tor.

V/TrimAdjusts the amount of control an external option, connected at A1/A1, has on the AVR.

DroopAdjusts the amount of cross-current compensation the AVR produces when a parallelingCT is connected to S1/S2.

UFROAdjusts the break point frequency for 100% 0.8 power factor load acceptance. This is thefrequency at which the generator set output voltage starts to drop.



Newage UFRO setting

100

90

80

70

60

50

045 50 54 58 59.5 600

Operating Frequency

95

Slide 8-4 UFRO setting for Newage AVRs

The Newage AVRs do not have switches to change the AVR operating characteristics like theOnan AVRs. The Newage AVRs use the UnderFrequency Roll-Off (UFRO) potentiometer to setthe frequency at which voltage starts to decrease.

To set the UFRO potentiometer, the technician has to actually change the generator set outputfrequency to the desire roll-off point and then set the AVR to that point.

• The technician first determines the type of load and the frequency at which the genset outputvoltage should start to drop off. Factory setting for 200 kW and up sets is 59.5 Hz. UPSloads may require the UFRO point to be lowered to 54 Hz to keep the voltage as steady aspossible when the UPS is trying to acquire the genset as a source.

• The technician makes sure that the load is disconnected from the genset and adjusts thegovernor to the proper frequency point.

• When the generator set has stabilized at the desired frequency, the technician turns theUFRO potentiometer until the UFRO LED is off, then back until the UFRO LED just lights.

• The UFRO LED should be lit when the genset is at the desired roll-off frequency.

• After the AVR is set, the technician resets the governor to the proper operating frequency.60 Hz for isochronous operation, 61.8 Hz for 3% droop, 63 Hz for 5% droop.



MX-321 Jumpers and Pots

3 2 1

DIP


S1 S2E0 E1 B0 B1

K1 K2 P2 P3 P4 XX X 6 7 8 1 2

RMS

NO LINK 6P - 506P - 604P - 504P - 60

FREQUENCYSELECTION

UNDER FREQUENCY

DWELL

DROOPOVER/VEXC

STABILITY

V/TRIMU V W

Under 90 kW90–550 kWOver 550 kW


TRIP

VOLTS

I/LIMIT

R21

ROLL OFF (UFRO)

Slide 8-5 AC Control Inputs and Outputs — MX321 (305-0623)

MX321 Adjustments

Over/VSets the 125% over voltage trip point. This pot, like the Volts/Hz on the 300-2880 AVR isfactory set and should not be adjusted in the field.

Exc TripSets the 300% current level point. This pot, like the Volts/Hz on the 300-2880 AVR isfactory set and should not be adjusted in the field.

DipSets the rate of drop of output voltage after the generator set frequency falls below theUFRO point.

DwellSets the maximum amount of time before the AVR forces the output voltage to start in-creasing back to normal after the generator set decreases below the UFRO point.

RMSSets the main operational characteristics of the MX-321. This pot, like the Volts/Hz onthe 300-2880 AVR is factory set and should not be adjusted in the field.



StabilityAdjusts the amount of dampening in the AVR regulation circuit. The higher the dampen-ing effect of this circuit, the slower the voltage changes.

VoltsAdjusts the AVR to a specific Reference Voltage with a particular load. This pot is ad-justed after the Optimum Response Jumper is set for a specific alternator size.

V/TrimAdjusts the amount of control an external option, connected at A1/A2, has on the AVR.

DroopAdjusts the amount of cross-current compensation the AVR produces when a parallelingCT is connected to S1/S2.

UFROAdjusts the break point frequency for 100% 0.8 power factor load acceptance. This is thefrequency at which the generator set output voltage starts to drop.

Jumpers

Frequency SelectionNo Link sets AVR for use with 6-pole 50 Hz set (1000 RPM).1–2 sets AVR for use with 6-pole 60 Hz set (1200 RPM)1–3 sets AVR for use with 4-pole 50 Hz set (1500 RPM)2–3 sets AVR for use with 4-pole 60 Hz set (1800 RPM)

Frequency Selection Jumper comes set from 1–3 and must be reset for 60 Hz operation.

Optimum ResponseA–B sets AVR stability circuit for 550–1500 kW alternator.B–C sets AVR stability circuit for 90–550 kW alternator.A–C sets AVR stability circuit for 20–90 kW alternator.

Optimum Response Jumper comes set from A–B.



VRAS-2 Shop Worksheet

S3

S1

S2

R-32

Volts

1 2 3 4 5 6 7 8 9 10

Do Not Adjustthis potentiometer

Slide 8-6 AVR Inputs and Outputs — VRAS-2


S2 Position

S1 1/2 Position

S1 3/4 Position

S3 1/2 Position

S3 3/4 Position

No-Load Exciter Voltage Current

Full-Load Exciter Voltage Current



SX-440 Shop Worksheet

S2S1A2A1

60 C 50

ÉÉÉÉÉÉ

V/TRIM

DROOP

VOLTS

STABILITY UFRO

BLUECAP.

A B C

IndicatorLED


Slide 8-7 AVR Inputs and Outputs — SX-440


Frequency Selection

Optimum Response Selection

Volts Pot

UFRO Pot





MX-321 Shop Worksheet

3 2 1

DIP


S1 S2E0 E1 B0 B1

K1 K2 P2 P3 P4 XX X 6 7 8 1 2

RMS

FREQUENCYSELECTION

UFRO

DWELL

DROOPOVER/VEXC

STABILITY

V/TRIMU V W


TRIP

VOLTS

I/LIMIT


Slide 8-8 AVR Inputs and Outputs — MX-321


Frequency Selection

Optimum Response Selection

Volts Pot

UFRO Pot

Stability Pot

Dip Pot

Dwell Pot



Integrated Generator Set Controls Lesson: Alternator Output Reconnection


Alternator Output Reconnection

This lesson presents an overview of reconnecting the output leads and the Current Transformers(CTs) on Onan and Newage alternators.

Objectives


• State the basic connections used when reconnecting alternator output windings.

• Identify Onan alternator winding markings.

• Identify Newage alternator winding markings.

• Identify the output voltage of an Onan or Newage alternator from the main statorconnections.

• Properly connect an Onan alternator simulator from a reconnection diagram.

• Properly connect a Newage alternator simulator from a reconnection diagram.

Cummins is a registered trademark of Cummins, Inc.Onan is a registered trademark of Onan Corporation.Newage is a trademark of Stamford Corporation.

Lesson: Alternator Output Reconnection Integrated Generator Set Controls


Alternator Winding Connections

Slide 9-1 Alternator Winding Connections

Alternator windings can be connected in two basic configurations:

Series Parallel

All Onan and Newage reconnectible alternators have six windings, and non-reconnectible Onanand Newage alternators have either three or six windings depending on their design. The wind-ings in the main stator can be either connected in Series or Parallel.

If the windings are connected in Series, the output voltage from one end of a pair of windingswill be twice the voltage of one winding. The current that these two windings can produce islimited by the current capacity of one winding.

If the windings are connected in Parallel, the output voltage from one end of a pair of windingswill be the same as the voltage of one winding. The current that these two windings can producewill be twice the current capacity of one winding.

Series winding connections produce twice as much voltage output as one winding.The current output is the same as that carried by one winding.

Parallel winding connections produce twice as much current output as one winding.The output voltage is the same as that produced by one winding.



Connecting Alternator Windings

Delta Wye or Star

Slide 9-2 Alternator Winding Connection Groups

Alternator windings that are connected in Series or Parallel can be further connected in twomajor connection groups; Delta, and Wye or Star

Delta connections are used for several reasons:1) Phase-to-phase current is 1.73 x the current in one phase.2) The neutral leg does not have to be grounded.

Wye or Star connections are used for several reasons:1) Phase-to-phase voltage is 1.73 x the voltage from any phase to neutral.2) Neutral lead is connected to Safety Ground at the service entrance of the building.

Type Voltage ∅ -N Voltage ∅ -∅ ∅ CurrentWye/Star V of 1 winding 1.73 * V of 1 winding I of 1 windingDelta V of 1 winding 2 * V of 1 winding 1.73 * I of 1 winding

Delta connections are used for more current and to reduce ground fault damage. Some delta con-nected alternators do not require a neutral or ground connection.

Wye connections are used for more voltage. Normally the neutral of a Wye alternator is con-nected to earth ground at the service entrance of the building.



Windings in Delta Connections

L1

L2

L3

L0

L1

L2

L3

L0

!"#

$%#&

Slide 9-3 Windings in Delta Connections

Delta alternator connections do not always include a neutral connection.

Series Delta connections

• may have a Neutral connection for single-phase loads

• may have just three output leads for three-phase loads.

• with a neutral connection between L1 and L3 will have a voltage between L2 and Neutralequal to 1.73 times the L1 or L3 to Neutral voltage.

Parallel Delta connections

• do not normally have a neutral connection and therefore cannot power single-phase loads.

• are sometimes used by power generation stations with Phase B (L2) connected to earthground as a neutral connection. This may confuse technicians seeing this connection andreading Zero Volts from Phase B to Neutral or to the safety ground.



Windings in Star Connections

L1L2

L3

L0

L1L2

L3

L0

Slide 9-4 Windings in Wye or Star Connections

Wye or Star alternator connections normally include a neutral connection. This connection willbe at the point where the three phases come together.

Series Wye or Star connections

• normally have a Neutral connection for single-phase loads.

Parallel Wye or Star connections.

• also normally have a Neutral connection for single-phase loads

• However, some Wye connections do not have a Neutral connection and therefore cannotpower single-phase loads.

All Wye or Star connected generator sets used with three-pole transfer switches must have theirNeutral connection tied to ground at the service entrance of the building.

All Wye or Star connected generator sets used as a separately-derived system with four-poletransfer switches must have their Neutral connection tied to ground at the generator set.



Non-Reconnectable Windings

'()

L1L2

L3

L0L1L2

L3

Slide 9-5 Non-reconnectible alternator windings

The lowest cost alternators are non-reconnectible. These alternators can only produce one or twooutput voltages while producing the rated kilowatt output of the generator set.

• The winding size limits the current through each winding to a low level.

• In a normal genset, when the voltage changes, the current changes inversely to maintain asteady kilowatt output.

• If the current cannot increase, when the voltage is decreased, the kilowatts produced by thegenerator set decreases.



Onan Winding Markings

**

*+

,

,

,+

,

,-

,.

,/

,0

,1

,

,,

*+,+

,.

,1

,

,

, ,-

,

,0

,,

,/

* *

Slide 9-6 Alternator Reconnection – Onan markings

Reconnectible Onan alternators have twelve output leads numbered from T1 to T12.

• T1, T4, T7 and T10 are always in the same output phase.



The older Onan alternators produced an output voltage which electrically rotated counter-clock-wise.

• This is the reverse of the standard utility direction.

• At that time, all US alternator manufacturers produced CCW rotating alternators.

Since Onan purchased Newage Engineers in 1984, all Onan alternators have had a clockwiserotating electrical output.



Onan Reconnection Diagram

*+23

,

,/

,-

,

,

,

,

,0

,

,1

,.

,+

,

,+

*243

*23

*2"3

,

%

-

.

/

0

5#

,!

%*

+/6.*

77+77-

7.

0/-

.

0/8.

-

#9

*

Slide 9-7 Sample Onan Reconnection Diagram

The sample Onan alternator reconnection diagram at the top of this page is just one of severalways to connect the output leads of an Onan alternator.

This diagram shows a Parallel Wye, Parallel Star or Low Wye connection.

Some things to note on this diagram are:

• On which side of the CTs the dots are located.

• Where the sensing leads connect to the alternator leads.

• Where the individual lead numbers are shown and in which output phase each number islocated.

The diagram also shows a tabulation for TB21 connections.

• The only windings that do not move are sensing leads 7 and 8.

• Onan AVRs always get their reference voltage from these two sensing leads.



Newer Newage Lead Markings

**

*+

4

4

4-

-

-

4.

..

*+

-

.

4

4

-

.4.

4-

* *

Slide 9-8 Alternator Reconnection – Newage markings

Reconnectible Newage alternators have twelve output leads numbered in three alpha-numericsequences from 1 to 6.

• U1, U2, U5 and U6 are always in the same output phase.

• V1, V2, V5 and V6 are always in the same output phase.

• W1, W2, W5 and W6 are always in the same output phase.

Newage Engineers alternators have a clockwise rotating electrical output when used with normalrotation Cummins engines.



Newage Reconnection Diagram

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4.

4-

4

4

.

-

.

-

,

,+

*243

*23

*2"3

,

"

4

-

.

/

0

4.

4-

4

4

.

-

.

-

":%

":%

5#

,!

%*

+/6.*

77+77-

7.

0/.

-

0/8.

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#9

Slide 9-9 Sample Newage Reconnection Diagram

The sample Newage alternator reconnection diagram at the top of this page is just one of severalways to connect the output leads of a Newage alternator.

The schematic and wiring diagrams show a Parallel Wye, Parallel Star or Low Wye connection.

Some things to note on the wiring diagram are:

• Where the sensing leads connect to the reconnection block.

• Which reconnection studs are connected by jumper links.

Some things to note on the schematic diagram are:

• On which side of the CTs the dots are located.

• Where the sensing leads connect to the alternator leads.

• Where the individual lead numbers are shown and in which output phase each number islocated.

The diagram also shows a tabulation for TB21 connections.



Alternator Reconnection – TB21

31

32

27

25

26

24

21

22

23

28

29

30

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,>

*-

*0

*.

*

*/

2?93

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23

Slide 9-10 Alternator Reconnection – TB21

TB21 is the main AC Control connection point inside the generator set control box.

• TB21 always has terminals marked from 21 to 32.

• Terminals 21 and 32 are the AC Starter Disconnect output (90–120 VAC) to the DC Controlboard (A11 ECM).

• The alternator output terminals connect to TB21 through sensing leads four through eight.

• This end of the sensing leads will not be moved, but when the generator set is reconnected,the other end may have to be moved.



Onan Reconnection Simulator

L1

L2

L3

L4

#

Slide 9-11 Alternator Reconnection – Onan Simulator

Using a Service Manual for an Onan alternator and an Onan alternator simulator, construct thefollowing connections:

• Parallel Wye (Star)

• Series Wye (Star)

• Series Delta

• Parallel Delta

After you have completed each connection, show it to your instructor for grading.Make sure you show your instructor the manual and diagram you used to create the connection.

Parallel Wye (Star) Connected properly Proper Manual Proper Diagram

Series Wye (Star) Connected properly Proper Manual Proper Diagram

Series Delta Connected properly Proper Manual Proper Diagram

Parallel Delta Connected properly Proper Manual Proper Diagram



Newage Reconnection Simulator

N

W

V

U

L1

L2

L3

L4

":#

Slide 9-12 Alternator Reconnection – Newage Simulators

Using a Service Manual for a Newage alternator and a Newage alternator simulator, constructthe following connections:

• Parallel Wye (Star)

• Series Wye (Star)

• Series Delta

• Parallel Delta

After you have completed each connection, show it to your instructor for grading.Make sure you show your instructor the manual and diagram you used to create the connection.

Parallel Wye (Star) Connected properly Proper Manual Proper Diagram

Series Wye (Star) Connected properly Proper Manual Proper Diagram

Series Delta Connected properly Proper Manual Proper Diagram

Parallel Delta Connected properly Proper Manual Proper Diagram



S&TT1/95

*+23

*243 *23

*2"3

"

4

Slide 9-13 Alternator Reconnection – Newage Cutaway alternator

After looking at the cutaway Newage alternator in the shop, draw the output connection for thisalternator in the above space.

What is this alternator connection called?

What would you expect for an output voltage from a alternator connected in this fashion?

What voltage would be sensed at the Automatic Voltage Regulator?

Lesson: Troubleshooting the AC ControlIntegrated Generator Set Controls


Troubleshooting the AC Control

This lesson presents an overview of troubleshooting the Onan and Newage AC Controls.

Objectives


• State the basic checks used with AC Controls.

• Identify Onan AC Control test points.

• Identify Newage AC Control test points.

• State the most common AVR Input Voltages.

• State the two most common causes of unstable output voltage.

• Describe how to test for load-induced voltage instability.

• Describe how to flash the field of a Cummins/Onan generator set.


Lesson: Troubleshooting the AC Control Integrated Generator Set Controls


AC Control Troubleshooting Diagram

X (+)

XX (–)

L1

L3

L2

ReferenceVoltage

Excitation

Exciter

ExciterRotor

Main Rotor

Main Stator

L0

CB21

(–) (+)

Stator

K1K2 Drive

RotatingDiodes

Voltage

Slide 10-1 AC Control Troubleshooting Diagram

Slide 10-1 is a block diagram showing the main parts of an AC Control System. The items in thedashed box (top) are rotating parts of the generator, and the items in the solid box (bottom) arestationary.

The Field Circuit Breaker in this Figure is shown as it would be connected for a NewageSX-440, SX-460, or MX-321 AVR. CB21 would be connected differently for an Onan AVR.

• Newage AVRs have the circuit breaker connected between terminals K1 and K2 on theAVR. In this connection, the actual DC exciter current flows through CB21. When thecircuit breaker opens in an overcurrent condition, the excitation voltage drops to zero andthe current through the exciter stator drops to zero.

• Onan AVRs use a circuit breaker in the AC Regulator Drive voltage circuit. Onan ACControls also use a Commutating Reactor (CMR21 or L21) which is not shown in Figure 1.CMR21 or L21 is in the regulator drive voltage circuit and helps to decrease noise to theAVR from non-linear loads..



AVR Inputs & Output

Slide 10-2 Basic AVR Inputs and Output

Every AVR has two inputs and one output.

INPUTS

• Sensing VoltageSample of the generator output voltage. This is usually 208 to 240 VAC

• Regulator Drive VoltageInput to the AVR that is rectified to produce the excitation voltage. This voltage can comefrom the generator output, or from a Permanent Magnet Generator (PMG). This is usually140 to 260 VAC.

OUTPUTS

• Excitation VoltageDC pulses to the exciter stator which, produces the generator output voltage when amplifiedthrough the generator. This is usually 2 to 20 VDC



AC Control System Flow Diagram

X (+)

XX (–)

L1L3

L2

ReferenceVoltage

Drive

Excitation

Exciter

ExciterRotor

Main Rotor

Main Stator

L0

CB21

(–) (+)

Stator

K1K2

RotatingDiodes

Voltage

Slide 10-3 AC Control System Flow Diagram

Each part in the AC Control System has an input (or inputs) and an output; refer to the abovediagram to see the “flow” through the generator system.

Part Name Input Output

AVR Sensing Voltage Excitation Voltage

Regulator Drive Voltage

Exciter Stator Excitation Voltage Magnetic Flux

Exciter Rotor Magnetic Flux 3-Phase AC Voltage

Rotating Diodes 3-Phase AC Voltage DC Voltage

Main Rotor DC Voltage Magnetic Flux

Main Stator Magnetic Flux 1-Phase AC or3-Phase AC Voltage



QUICK CHECKS FOR AC CONTROLS

This set of quick checks assumes that the generator does not have proper output voltage. Thereare some basic checks that can be done to check the AC control system.

First, stop the generator set and disconnect the exciter stator leads from the exciter stator andinsulate them so they cannot short or be grounded.

Second, start the generator set and check for output voltage at the main stator terminals.

1. Is there residual voltage at the output of the Main Stator windings when the exciter leadsare disconnected? (LV 5–20 VAC, MV 5% of Output)

• YES: The main stator windings are good.

• NO: The main stator windings are not good. Check resistance as shown in the ServiceManual.

2. If the residual voltage is good, stop the set and reconnect the exciter leads to the exciterstator. Start the set. Has the output voltage increased?

• YES: Adjust the Coarse Voltage Adjust pot on the AVR.

• NO: Check to see that CB21 is closed. If CB21 is OK, flash the field using the procedure inthe Service Manual.

3. When you flash the field, does the output voltage from the Main Stator increase?

• YES: The Exciter Stator, Rotating Diodes and Main Rotor are OK.

• NO: There is a problem with the Exciter Stator, Exciter Rotor, Rotating Diodes, or MainRotor. Perform checks as shown in the Service Manual.

4. If the output voltage increased when you flashed the field, does the output stay up whenthe flash is removed?

• YES: The Exciter Stator, Rotating Diodes, Main Rotor and AVR are OK.

• NO: There is a problem with the Automatic Voltage Regulator. Perform checks as shown inthe Service Manual.

5. Put a full load on the generator set. Does the generator set output stay up after thegenerator set has responded to the load?

• YES: The generator set is OK.

• NO: Check Rotating Diodes. Replace them if any diode is open or shorted.



Flashing The Field

(+)

(–)

L1

L3

L2

ReferenceVoltage

Exciter

Main Stator

L0

CB21

Stator

AVR

(+)(–)

NOTE: Connect battery + terminal to AVR + exciter terminal.Connect battery – terminal through a resistor or lampand a diode to prevent battery damage.

300 Volt, 5 Amp diode

Slide 10-4 Flashing the Field

If the generator is disassembled or dropped, the residual magnetism in the main rotor can be re-duced enough so the regulator cannot get itself started with the residual voltage out of the mainstator windings.

Onan recommends that you use the resistors listed in the following chart, or a light bulb, as acurrent limiting device when flashing the field of a generator set.

• 6 Volts = 10 Ohms



DO NOT Flash the field for more than five (5) seconds, or you may damage the regulator or theexciter stator windings. Make sure you have a diode in the field flash apparatus you use to pre-vent the regulator from overcharging the battery. Batteries can explode when overcharged.

The field flash apparatus (shown in heavy lines should be touched to either the exciter terminalsat the regulator, or at the exciter stator. Make sure you observe proper polarity when connectingthe field flash circuit. Remember, the exciter field circuit is not referenced to ground, so youhave to touch both of the exciter terminals to create a current flow in the exciter stator winding.



Two Most Common Failures

X (+)

XX (–)

L1L3

L2

SensingVoltage

Drive

Excitation

Exciter

ExciterRotor

Main Rotor

Main Stator

L0

CB21

(–) (+)

Stator

K1K2

Voltage

Slide 10-5 The two most common causes of unstable output voltage

Most AC controls and generators work properly. However, sometimes you will come upon agenerator set which will not produce voltage, or the voltage is unstable, or the voltage is slightlyhigh or low.

• The most common genset failure which causes unstable output voltage is the R21 variableresistor. This resistor vibrates when the generator set operates. This can cause corrosionbetween the resistor terminals and the wires connecting to these terminals. The connectionsthen “make and break” as the control panel moves. This causes the voltage adjust circuit tochange resistance and the output voltage changes also.

• The second most common cause of unstable output voltage is a failure or loose connectionin the rotating diodes. When these connections “make and break” the current going to themain rotor changes and the output voltage also changes.

To determine if the cause of the problem is in the genset or the load, disconnect the load from thegenerator set and run the set. If the output voltage is steady, the problem is most likely a load-in-duced problem. If the output voltage is unstable, the problem is in the generator set.

Load-Induced Problems:Harmonic generation, unbalanced loads, non-linear loads are the three most common load-induced problems.



Questions to ask yourself and others1. Has anyone worked on the set recently? What did they do?

Maybe the last work was done improperly, or the part that was installed has failed.

2. What was happening just before the problem started?Was the load changed recently? Did the sound of the generator change in any way? Werethere any different sounds or smells from the generator recently?

3. Are all components connected properly?One of the best things that a technician can do to solve a problem is to perform a goodvisual inspection. Many times you will find possible future problems that you can preventfrom becoming failures when they are repaired early.

Common Failures1. Because of vibration and ageing, a bad remote voltage adjust potentiometer (R21) is the

most common cause of unstable output voltage.

2. The second most common cause of unstable output voltage is bad rotating diodes.

3. The third most common cause of unstable output voltage is a non-linear load on thegenerator set which overpowers the AVR and the load ends up controlling the voltage.



Troubleshooting AC Controls

L1L3

L2

L0AVR

MagneticCouplingMagnetic

Coupling

CB21

Slide 10-6 AC Control Troubleshooting Diagram

When troubleshooting a problem in an AC Control System, you have to remember that somethings are easier to check than others.

For instance, you cannot check anything on the rotating portion of the generator without doingsome sort of disassembly of the generator set.

To become an expert troubleshooter, it helps to think of the generator set and its three majorparts (engine, AC control, DC control) as systems of related components. When looking for apossible failed part in the AC Control system, it helps to know what the proper indication wouldbe at the point you are going to check.

The easiest place to check Reference Voltage is usually at TB21 inside the control box. TheReference Voltage into the AVR is always on terminals 22 and 23. The MX-321 has threevoltages on TB21 terminals 22, 23, and 25 since it measures all three phases of the outputvoltage.

The easiest place to check Excitation Voltage is usually at the Exciter Stator terminals F1 / F2 orX / XX.



Easy-Likely Troubleshooting ChecksThere are four common problems that are seen in AC Controls:

• No output voltage

• Low output voltage

• High output voltage

• Unstable output voltage

No Output Voltage

If there is Reference Voltage into the AVR and no Excitation Voltage out of the AVR, there areseveral things that can be checked.

• If the AVR is an Onan VRAS-2, is there a jumper between terminals 3 & 4 of the AVR? Ifthere is no jumper on the AVR, there will not be any Regulator Drive input to rectify intoExcitation.

• If the AVR is a Newage AVR, check to see that terminals K1 and K2 are connected with ajumper or the CB21 circuit breaker.

• Check to see that the Field Circuit Breaker (CB21) is connected and makes a completecircuit to the AVR.

Low Output Voltage

• Check Coarse Volts pot on the AVR.

• Check connection of T21 for older Onan generator sets.

• Check ampere load of generator set to see if the generator set is overloaded.

• Check to see if “UFRO” LED is lit on Newage AVRs.

• Check connection of generator output leads.

• Check rotating diodes.



Easy-Likely Troubleshooting Checks

High Output Voltage

• Check Over Voltage pot setting and connections.

• Check Coarse Volts pot on the AVR.

• See if the “I/Limit” or “EXC Trip” pots have been changed on the AVR.

Unstable Output Voltage

• Check R21 condition and connections.

• Check kW meter against calculated KVA to see if load power factor is out of allowablerange and overloading the generator set.

• Check “Stability” pot and adjust if needed.

• Check frequency at which the “UFRO” LED lights, and adjust if needed.




Cummins is a registered trademark of Cummins Engine CompanyPowerCommand is a Registered Trademark of Onan CorporationPowerful Solutions is a trademark of Onan Corporation

Documents

932-1005 Detector Participants Guide