EEM 42 Three Phase Asynchr Machines Dahlander Motor

Course"EEM 42 Three-phase asynchronous machines: Dahlander

motors"

Picture source: SEW Eurodrive

SH5002-1H Version 2.1

Author: M.Germeroth

Lucas-Nülle GmbH · Siemensstraße 2 · D-50170 Kerpen (Sindorf) Phone: +49 2273 567-0

www.lucas-nuelle.de

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Copyright © 2008 LUCAS-NÜLLE GmbH. All rights reserved.

LUCAS-NÜLLE Lehr- und Messgeräte GmbH

Siemensstraße 2 D-50170 Kerpen

EEM42 Three-phase asynchronous machines

Training objectives 1Equipment - 300W Classic Series 2Safety 3Asynchronous motor, Dahlander circuit 5

Connection and starting 7Rotation reversal 15Load characteristic 21

Copyright 31

EEM42 Three-phase asynchronous machines

EEM42 Three-phase asynchronous machines Training objectives

This course is intended to impart a practical knowledge of three-phase asynchronous machines. Experiments focus on investigating the functionality, response and effect of three-phase asynchronous motors with polarity reversal according to Dahlander .

Training objectives

Motor operation Nominal data, rating plate Delta connection, double-star connection Dahlander pole reversal Measurement of phase-to-phase and line-to-linevariables Rotation reversal Power measurement with and without mechanical loads

Prerequisites

Fundamentals of electrical machines Fundamentals of electrical engineering Use of measuring equipment

Welcome to the three-phase asynchronous machines course. The LUCAS-NÜLLE team wishes you lots of fun and success in working through the course subjects and conducting the experiments. The following pages provide an overview of the topics and required materials.

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EEM42 Three-phase asynchronous machines Equipment - 300W Classic Series

SO3636-6V servo drive/servo brake, 300 W 1 SE2662-2A Coupling sleeve, 300 W 1 SE2667-2B Coupling guard, 300 W 1

SE2672-3KThree-phase motor with squirrel cage rotor, 300 W

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SO3212-5U Power supply for electrical machines 1 SO3212-2H Dahlander pole reverser 1

SO5127-1ZAnalog/digital multimeter, wattmeter, power-factor meter

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SO5148-1F Set of 47 safety connecting leads, 4 mm 1 SO5126-9X Safety connection plug, 19/4 mm 15 SO5126-9Z Safety connection plug, 19/4 mm, with tap 5

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EEM42 Three-phase asynchronous machines Safety

Basic safety instructions

In all experiments using mains voltages, high, life-threatening voltages arise. For that reason use only safety measurement leads and make sure that there are no short-circuits.

It is imperative that all of the devices, which are provided with an earth or where earthing is possible, must be earthed. This is particularly the case for the frequency converter being used.

Always be very careful to check the wiring of the application modules and only switch on the mains voltage after a check has been completed. Whenever possible use a robust current monitoring instrument in the circuit..

Always use shaft-end guards and coupling guards as protection against contact with rotating motor parts.

All locally applicable stipulations and standards governing how electrical equipment is handled must be complied with.

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EEM42 Three-phase asynchronous machines Safety

General instructions on handling the equipment

Check that the knurled screws at the base of the motor and the coupling sleeves (power grip) on the motor shaft are all securely fastened.

Use shaft and coupling guards. Any prolonged running of the machines when operating under high loads can

subject the machines to excessive heating. The extreme case of the machine being prevented from rotating entirely may

only arise briefly. All of the machines are equipped with a thermal circuit-breaker, which triggers

when the maximum permissible operating temperature is exceeded. These switching contacts are accessible on the terminal board and must always be connected to the corresponding connection sockets of the mains supply and control unit.

All measurements have been recorded using conventional measuring instruments (primarily class 1.5) at the standard mains voltage (230/400V +5% -10% 50Hz) using standard production machines. Experience suggests that measurements will lie within the tolerance range of +/-15% with respect to the specified measurement. For more information on this please refer to VDE0530.

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EEM42 Three-phase asynchronous machines Asynchronous motor, Dahlander circuit

Asynchronous motor, Dahlander circuit

Connection and starting Rotation reversal Load characteristic

The following exercises involving an asynchronous motor and Dahlander circuit are conducted on the next few pages:

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6


Enter the nominal data for the asynchronous machine

Training content: "Connection and starting"

Identify the terminal connections of the motor and operate the motor as a three-phase asynchronous motor on a three-phase mains network

Utilise the nominal data of the motor based on the rating plate Measure the phase voltage and phase current Put the motor into operation with a Dahlander pole reverser Identify the differences between delta and double star

connections Understand the function of a pole reverser Put the motor into operation with the brake Subject the motor to load

Nominal power (delta) ____W

Nominal power (doublestar) ____W

Nominal voltage ____V

IN delta ____A

IN double star ____A

cos φ (delta) ____

cos φ (double star) ____

Rated speed (delta) ____rpm

Rated speed (double star) ____rpm

Frequency ____Hz

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Assembly instructions: "Connection and starting"

Additional More detailed information on the brake can be found in the corresponding online documentation

Circuit diagram: "Connection & starting"

Assemble the circuits as specified in the following circuit diagram and

set-up instructions Switch on the brake. This does not yet subject the motor to any load

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Set-up: "Connection & starting"

Starting asynchronous motor with switch in position 1

Required settings:

Brake mode: Torque control

Experiment procedure:

Put the motor into operation and observe its response Brake the motor down to its nominal speed At the same time measure the phase variables Uphase and Iphase

Make sure that the ammeter and voltmeters have been connected properly

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Specify the type of connection.

What do you measure the torque to be with the switch on setting 1?

What do you measure the phase variables Uphase and Iphase to be?

Starting asynchronous motor with switch in position 2

Required settings:

Brake mode: Torque control


Put the motor into operation and observe its response Brake the motor down to its nominal speed Measure the phase variables Uphase and Iphase

Make sure that the ammeter and voltmeters have been connected properly

Star connection

Delta connection

Double star connection

M= ____Nm

Uphase= ____V

Iphase= ____A

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Specify the type ofconnection.

What do you measure the torque to be with the switch on setting 2?

What do you measure the phase variables Uphase and Iphase to be?

Star connection

Steinmetz connection

Double star connection

M= ____Nm

Uphase= ____V

Iphase= ____A

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Record a load characteristic for both switch positions

Required settings:

Brake mode: Speed control


Record a load characteristic in each case (switch positions 1 & 2) for delta and double star connections.

Brake the motor to the speeds stipulated in the table. Enter the measured values (M, Iphase) in the tables.

Table 1 (Switch position 1)

n/(1/min) 1400 1320 1240 1160 1080 1000M/Nm

I/A

1000 1050 1100 1150 1200 1250 1300 1350 1400 1450 1500n/(1/min)

0.0

0.5

1.0

1.5

2.0

2.5

3.0

3.5

4.0

4.5

5.0

M/N

m

0.00

0.25

0.50

0.75

1.00

1.25

1.50

1.75

2.00

2.25

2.50

2.75

3.00

I/A

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Table 2 (Switch position 2)

Record load characteristics for both switch positions with the ActiveDrive/SimuLoad software

Required settings:

Brake: PC mode

n/(1/min) 2800 2640 2480 2320 2160 2000M/Nm

I/A

2000 2100 2200 2300 2400 2500 2600 2700 2800 2900n/(1/min)

0.0

0.5

1.0

1.5

2.0

2.5

3.0

3.5

4.0

M/N

m

0.00

0.25

0.50

0.75

1.00

1.25

1.50

1.75

2.00

2.25

2.50

2.75

3.00

I/A

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Start the ActiveDrive/ActiveServo software. Select speed control operating mode. The motor is to be braked in 20 steps till it stops. ( Note: in

ActiveDrive/ActiveServo, enter the required number of steps under "Presets" -> "Default" -> "Ramp".)

The asynchronous motor's load characteristics are to be recorded for delta and double star connections.

Start with a delta connection. Both load characteristics are to be recorded on one graph. Label and scale the graph as indicated by the placeholder. The following parameters are to be recorded:

Torque M(n) Mechanical power P2(n)

After measurement is complete, export the resultant graph and copy it into the placeholder below.

Save the settings for the ActiveDrive/ActiveServo software for future experiments in a file named "eem42_LoadCharacteristic".

Placeholder for load characteristic (delta and double-star connection)

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Definition of rotation direction If you look at the drive shaft end of the asynchronous machine from the perspective of the working machine (in our case the brake), the rotating direction is positive when it is clockwise. If the motor has two workable shaft ends, then it is the shaft end opposite the cooling vents, collector or slip-rings that is the shaft end which defines the rotation direction.

Training content: Rotation reversal

Identify the difference between clockwise and anti-clockwise rotation

Start the motor in both rotation directions

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Assembly instructions: Rotation reversal

More detailed information on the brake can be found in the corresponding online documentation

Circuit diagram: Rotation reversal

Assemble the circuits as specified in the circuit diagrams and set-up

instructions below. Switch on the brake. This does not yet subject the motor to any load.

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Set-up: Rotation reversal

Rotation reversal


Switch on the motor and observe it.

In which direction does the motor turn?

The motor turns clockwise.

The motor turns anti-clockwise.

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Switch off the motor and change its wiring as shown in the diagram below. Start the motor again and observe it.

Circuit diagram: Rotation reversal

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In which direction does the motor turn?

How can a three-phase asynchronous machine's direction of rotation be changed?

The motor turns clockwise.

The motor turns anti-clockwise.

By exchanging any two phases.

Simply by exchanging L2 & L3

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Assembly instructions: "Load charactacteristics"

Additional More detailed information on the brake can be found in the corresponding online documentation.

Training content: Load characteristics

Simulate various loads (load machines) with the ActiveDrive/ActiveServo software

Set parameters using the software with load-specific values (load constant and moment)

Record and evaluate characteristics for various operating points Determine the motor's response to different loads

Assemble the circuits as specified in the following circuit diagram and

set-up instructions Switch on the brake. This does not yet subject the motor to any load

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Circuit diagram: Load characteristic

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Set-up: Load characteristic

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Record the load characteristic with various simulated loads useing the ActiveDrive/ActiveServo software

Record characteristic in double-star/delta mode with a pump/fan load.

Required settings:

Brake: PC mode

The settings stipulated below should then be made for the ActiveDrive and SimuLoad software.

Load machine: Pump/fan Load constant: refer to the experiment procedure. Under "View" => "Measured Value Display", select all mechanical and

electrical variables except for slip.


Start the "ActiveDrive / ActiveServo" software and initially open the file "eem42_load characteristic" (see "connection and starting")

Then carry out the required settings The following parameters are to be recorded in this measurement:

torque M(n) Switch the motor on directly using Stage 1 in the second step (double star

configuration) Start the measurement and slowly increase the load constant "l" until the line

current I/A shown in the parameter dialog corresponds to the value of IN-double star.

Now store the first operating point Now switch back to Stage 1 (delta) and wait a brief moment. Now store the

second operating point. Now after completing the measurement export the diagram into the

appropriate place holder reserved for it below Now store the settings under the file name "eem42_pump-fan"

More information on the pump/fan load machine and definition of the constant I

can be found in the online documentation for the ActiveDrive/ActiveServo software.

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Placeholder for pump/fan load characteristic (delta and double-star connection)

Enter the measured values for the double star operating point

M = ____Nm

n = min-1

P2 = ____W

P1 = ____W

η = ____%

S = ____VA

Q = ____Var

cos φ = ____U = ____V

I = ____A

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Enter the measured values of the delta operating point

How would you describe the load characteristic for the pump/fan?

Assume that instead of stage 1, you had set the load constant I to stage 2 corresponding to the motor's power rating. Would the mechanical output then have been larger, equal or smaller?

M = ____Nm

n = min-1

P2 = ____W

P1 = ____W

η = ____%

S = ____VA

Q = ____Var

cos φ = ____U = ____V

I = ____A

Linear

Quadratic

Cubic

Larger

Equal

Smaller

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Record characteristic in star/delta starting mode with a lifting drive as the load machine

Required settings:

Brake: Industrial series: PC mode

Make the settings stipulated below for the ActiveDrive and ActiveServo software.

Load machine: Lifting drive Load moment: refer to the experiment procedure. Under "View" => "Measured Value Display", select all mechanical and

electrical variables except for slip.


Start the software and begin by opening the file "eem42_loadcharacteristic" (see "conneciton and starting")

Then carry out the required settings The following parameter(s) are to be recorded during this measurement:

torque M(n) Switch the motor on directly through Stage 1 to the second stage (double star

connection) Start the measurement and slowly increase the load torque "Nm" until line

current I/A shown in the parameter dialog corresponds to the value of IN-double star.

Now store the first operating point Now switch back to stage 1 (delta) and wait a brief moment. Now store the

second operating point. After successful measurement export the diagram created and place it in the

appropriate placeholder below Store teh settings under the file name "eem42_liftingdrive"

More information on the lifting drive load machine and load moment definition can be found in the (online) documentation for the ActiveDrive/ActiveServo software.

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Placeholder for lifting drive load characteristic (delta and double star connection)

Enter the measured values of the double star operating point

M = ____Nm

n = min-1

P2 = ____W

P1 = ____W

η = ____%

S = ____VA

Q = ____Var

cos φ = ____U = ____V

I = ____A

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Enter the measured values of the delta operating point

What does a comparison between the values of P2 measured at the two operating points reveal?

Using the formulae below, calculate the ratios (x1 & x2) between the torques measured at operating points 1 and 2 for the two load machines.

M = ____Nm

n = min-1

P2 = ____W

P1 = ____W

η = ____%

S = ____VA

Q = ____Var

cos φ = ____U = ____V

I = ____A

P2 remains constant.

P2 almost doubles.

P2 only depends on the speed.

P2 depends on both speed and load moment.

More than one answer may be correct.

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Specify the calculated torque ratios "x1" and "x2".

Compare the torque ratios for both load machines. Which statements are correct?

x1= ____

x2= ____

The ratios are nearly identical.

The torque ratio of the lifting drive load machine is 1, because the load moment is identical at both operating points.

The torque ratio of the pump/fan load machine is based on the relationship M ~ n 2, or M2/M1~(n2/n1)2

The torque ratio of the pump/fan load machine is based on the relationship M ~ n 3, or M3/M1~(n2/n1)3

More than one answer may be correct.

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EEM42 Three-phase asynchronous machines Copyright

Copyright © 2004-2008 LUCAS-NÜLLE GmbH.

This course "EEM 42 Three-phase asynchronous machines: Dahlander motors" is protected by copyright. All rights pertaining thereto are reserved. Any reproduction of the document as a file or in written form be it photocopy, microfilm or any other method or conversion into a machine-compatible language, in particular for data processing systems, without the expressed written approval of the LUCAS-NÜLLE GmbH is strictly forbidden.

The software as described above is made available on the basis of a general licensing agreement or in the form of a single license. The use or reproduction of the software is only permitted in strict compliance with the contractual terms stated therein.

If changes have been performed in a manner which was not strictly authorised by the LUCAS-NÜLLE GmbH, any product liability or warranty claims pertaining thereto are null and void.

Congratulations! This is the last page. You have completed the course "EEM42 Three-phase asynchronous machines: Dahlander motors".

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Lucas-Nülle Lehr- und Meßgeräte GmbHSiemensstraße 2 · D-50170 Kerpen-Sindorf

Telefon +49 2273567-0 · Fax +49 2273567-30

www.lucas-nuelle.de

Documents

EEM 42 Three Phase Asynchr Machines Dahlander Motor