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Previous Issue: New Next Planned Update: 1 January 2009

Page 1 of 7Primary contact: Khaleel M. Al-Hussain on 873-0311

Best Practice

SABP-G-005 29 December 2004Synchronous Motors DynamicAnalysis Factory Acceptance Test

Document Responsibility: Consulting Services Department

Saudi Aramco DeskTop Standards

Table of Contents

1 Introduction.................................................... 22 References.................................................... 23 General.......................................................... 34 Definitions...................................................... 35 Vibration Detectors........................................ 46 Tests Procedure............................................ 47 FAT Acceptance Criteria................................ 5

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Document Responsibility: Consulting Services Dept. SABP-G-005

Issue Date: 29 December 2004 Synchronous Motors Dynamic

Next Planned Update: 1 January 2010 Analysis Factory Acceptance Test

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1 Introduction

1.1 Purpose

The purpose of this Practice is to establish guidelines in reviewing the dynamicanalysis of synchronous motors during Factory Acceptance Test (FAT).

1.2 Scope

This Best Practice gives general guidelines for reviewing vibrationinstrumentation requirements, test procedure and acceptance limits during the

Factory Acceptance Test and does not include performance test criteria.

1.3 Disclaimer

This Best Practice is being provided for the general guidance and benefit ofSaudi Aramco engineers attending synchronous motor Factory Acceptance Test

(FAT). The use of this Best Practice during factory acceptance test, however,

does not relieve the manufacturer from his responsibility or duty to confirm or toverify the accuracy of any information presented or from his contractual liability

to perform an accurate FAT that conforms to Mandatory Saudi Aramco

Engineering Requirements. The use of the information or material containedherein will not guarantee that the resulting product satisfies the applicable

requirements of Saudi Aramco Standards. Saudi Aramco assumes no

responsibility or liability whatsoever for any reliance on the information

presented herein or for FAT performed by manufacturer in accordance with thisBest Practice document. Moreover, this Best Practice is intended only to

provide guidelines for Saudi Aramco engineers attending the Factory

Acceptance Test and shall not be considered as a replacement for the MandatorySaudi Aramco Engineering Requirements. Saudi Aramco is a registered

trademark of the Saudi Arabian Oil Company. Copyright, Saudi Aramco, 2004.

1.4 Conflicts with Mandatory Standards

In the event of a conflict between this Best Practice and other Mandatory SaudiAramco Engineering Requirement, the Mandatory Saudi Aramco Engineering

Requirement shall govern.

2 References

This Best Practice is based on the below referenced standard:

2.1 Saudi Aramco References

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Document Responsibility: Consulting Services Dept. SABP-G-005

Issue Date: 29 December 2004 Synchronous Motors Dynamic

Next Planned Update: 1 January 2010 Analysis Factory Acceptance Test

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Saudi Aramco Engineering Standard

SAES-P-113 Motors and Generators (31 July, 2004)

Saudi Aramco Materials System Specifications

17-SAMSS-520 Form-Wound Brushless Synchronous Motors

(28 January, 2004)

34-SAMSS-625 Machinery Protection Systems (30 June, 2002)

2.2 Industry Codes and Standards

American Petroleum Institute (API)

API STD 546 Brushless Synchronous Machines-500 KVA andLarger, 2

ndEdition

API STD 670 Machinery Protection Systems, 4th

Edition3 General

This best practice gives general guidelines for the vibration instrumentationrequirements, test procedure and acceptable limits during synchronous motorsfactory acceptance test. If rotordynamic analysis is required, according to

17-SAMSS-520/API STD 546, then it should be reviewed by the attendee prior to

the test.

The vendor shall notify the purchaser not less than ten working days before the datethe equipment will be ready for testing (API STD 546/ P 4.3.1.2). However, it is

suggested that the vendor send notification six weeks prior to any witness test.

At least 6 weeks before the first scheduled test, the vendor shall submit to thepurchaser, for review and comment, detailed procedures for all tests, including

acceptance criteria for all monitored parameters (API STD 546/ P 4.3.1.4).

4 Definitions

Factory Acceptance Test (FAT): It is a test conducted at a factory to ensure that themotor meets its required performance and mechanical integrity.

Acceptance Level: This is the vibration level (displacement, velocity, or acceleration)

at which a machine can run indefinitely without inducing vibration related maintenance.

Cold start: A motor start that occurs when the rotor and stator are initially at ambienttemperature (API STD 546/ P 1.5.7).

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Document Responsibility: Consulting Services Dept. SABP-G-005

Issue Date: 29 December 2004 Synchronous Motors Dynamic

Next Planned Update: 1 January 2010 Analysis Factory Acceptance Test

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Hot start: Any restart of the motor that occurs when the motor is at a temperatureabove ambient temperature (API STD 546/ P 1.5.8).

Lateral critical speed: Corresponds to resonant frequencies of the rotor, bearings, andbearing support system (API STD 546/ P 1.5.9).

Trip speed (in RPM): The speed at which the independent emergency speed deviceoperates to shut down the machine (API STD 546/ P 1.5.13).

5 Vibration Detectors

Vibration detection equipment shall be provided as per the below Table.

Table-1: Required Vibration Instrumentation for Synchronous Motors

Relative MeasurementSeismic MeasurementReading at the monitorHP Rating

Radial Thrust Key Velocity Acceleration

> 250 HP Motor withAntifriction Bearings

One /radial Brg.

250 -500 HP Horizontal

(Hydrodynamic Radial Brg.)One /radial Brg.

500 -1000 HP Horizontal(Hydrodynamic Radial Brg.)

Provisionsfor X&Y

Provision One /radial Brg.

> 1000 HPHorizontal(Hydrodynamic Radial Brg.)

X & Y Yes

> 250 HPVertical MotorTwo on the top

radial Brg.

* Special Purpose Motorwith Hydrodynamic Radial& Thrust Brgs.

X & Y Dual Yes

* Special Purpose Motors are the motors that drive high-inertia loads, vertical machinesthat support high thrust loads, part of a complete train requiring vibration sensitivitycriteria, operate in abnormally hostile environments, or are critical unspared equipment(API STD 546 paragraph 1.1.1 Note 2).

Vibration detectors shall be provided, installed and calibrated in accordance with

34-SAMSS-625.

6 Tests Procedure

6.1 For motors 2000 kW (2682 HP) and above which operate at or above 3600

RPM, the vendor shall provide a damped unbalanced response analysis for eachspeed from zero to 115% of the maximum operating speed (17-SAMSS-520/ P

2.4.6.2.2).

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Document Responsibility: Consulting Services Dept. SABP-G-005

Issue Date: 29 December 2004 Synchronous Motors Dynamic

Next Planned Update: 1 January 2010 Analysis Factory Acceptance Test

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6.2 Bearing housing overall velocity should be measured in in/sec (mm/sec) RMSand shaft vibration in mils (m) pk-pk.

6.3 The combined total electrical and mechanical runout for radial position probesshall not exceed 0.35 mils (9 m) for machines operating at 1800 RPM or less,

or 0.25 mils (6 m) for machines operating above 1800 RPM. If the combined

runout exceeds these values, reasonable attempts shall be made to reduce the

runout. After all reasonable attempts are made to reduce the runout, 0.5 mils (13m) will constitute an acceptable combined runout level. Records of runout

tests before and after attempts to correct excessive runout shall be available for

inspection on request (17-SAMSS-520/ P 2.4.5.1.3).

6.4 The combined total electrical and mechanical runout for axial position probesshall not exceed 0.5 mils (13 m) (API STD 546/ P 2.4.5.1.3).

6.5 vibration shall be measured to determine the mechanical performance and

acceptability of all machines. This test is to be performed during the bearingtemperature rise test and, hot run test.

7 FAT Acceptance Criteria

7.1 Before mounting the coupling, the machine shall be properly mounted on amassive foundation and run until the bearing temperatures stabilize. The voltage

shall be reduced to of rated to minimize electrically induced vibration and lX

filtered vibration data taken without the coupling mounted and again after

mounting the coupling. The magnitude of the vectorial change in the lXvibration on the shaft and bearing housings shall not exceed 10% of the

vibration limits given in Figures 1 and 2 (API STD 546/ P 4.3.1.5.2).

7.2 During the test with rated voltage, the rotor shall be maintained on magneticcenter. With the coupling mounted, the voltage shall be increased to rated and a

complete set of filtered and unfiltered vibration data shall be taken. All data

shall be within the limits given in Figures 1 and 2. If the vibration change oramplitude exceeds the allowable limits, the vendor and purchaser shall mutually

agree on the appropriate corrective action (API STD 546/ P 4.3.1.5.2).

7.3 Motors purchased with the driven equipment and generators purchased with

drivers shall additionally meet the following requirements, when coupled to thedriven equipment and operated at rated voltage and speed. The maximum shaft

relative motion shall not exceed (17-SAMSS-520/ P 2.4.6.4):

i 25.4 x (8,000/N)0.5

micrometers [(8,000/N)0.5

mils] or 38 micrometers(1.5 mils), whichever is less where N is the synchronous speed in RPM. If

the final probe track runout exceeds 6 micrometers (0.25 mils), then the

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Document Responsibility: Consulting Services Dept. SABP-G-005

Issue Date: 29 December 2004 Synchronous Motors Dynamic

Next Planned Update: 1 January 2010 Analysis Factory Acceptance Test

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vibration readings shall be phase compensated for the measured final

runout in order to determine the true vibration readings.

ii The maximum bearing housing velocity, in any direction, shall not exceed3 mm/s (0.12 in/sec) RMS.

Figure-1 (API STD 546): Shaft Vibration Limits (Relative to Bearing Housing UsingNoncontact Vibration Probes): For all Hydrodynamic SleeveBearing Machines; With the Machine Securely Fastened to aMassive Foundation.

Notes:

1. The unfiltered vibration limits for machines up to 3,600 rpm rated speed shall not exceed

2 mils p-p displacement. For machines with rated speeds in excess of 3,600 rpm, theunfiltered vibration limit shall not exceed N/12000 where N is the maximum rated

continuous speed.

2. Vibration displacement at any filtered frequency below running-speed frequency shall notexceed 0.1 mil or 20% of the measured unfiltered vibration displacement, whichever isgreater.

3. Vibration displacement at any filtered frequency above running-speed frequency shall notexceed 0.5 mil peak-to-peak.

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Document Responsibility: Consulting Services Dept. SABP-G-005

Issue Date: 29 December 2004 Synchronous Motors Dynamic

Next Planned Update: 1 January 2010 Analysis Factory Acceptance Test

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4. Vibration displacement filtered at running speed frequency shall not exceed 80% of theunfiltered limit (runout compensated).

Figure-2 (API STD 546): Bearing Housing Radial and Axial Vibration Limits:For Sleeve and Antifriction Bearing Machines; With theMachine Securely Fastened to a Massive Foundation.

Notes:

1. The filtered and unfiltered vibration limits for machines up to 1,000 rpm rated speed shallnot exceed 1.6 mils p-p displacement, and 0.1 inches per second true peak velocity formachines with rated speeds above 1,000 rpm.

2. For unfiltered vibration limits, use the machine synchronous or maximum rotational speed inrpm.

3. For filtered limits, use vibration frequency in hertz.

4. Limits are for sleeve and anti-friction bearing machines.

Revision Summary29 December, 2004 New Saudi Aramco Best Practice.