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Electricity and New Energy Three-Phase Wound-Rotor Induction Machines Courseware Sample 86367-F0

Three-Phase Wound-Rotor Induction MachinesThree-phase wound-rotor induction machine starting current and torque versus the rotor resistance 7KUHH SKDVH ZRXQG URWRU LQGXFWLRQ PDFKLQHV

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Page 1: Three-Phase Wound-Rotor Induction MachinesThree-phase wound-rotor induction machine starting current and torque versus the rotor resistance 7KUHH SKDVH ZRXQG URWRU LQGXFWLRQ PDFKLQHV

Electricity and New Energy

Three-Phase Wound-Rotor Induction Machines

Courseware Sample86367-F0

Page 2: Three-Phase Wound-Rotor Induction MachinesThree-phase wound-rotor induction machine starting current and torque versus the rotor resistance 7KUHH SKDVH ZRXQG URWRU LQGXFWLRQ PDFKLQHV
Page 3: Three-Phase Wound-Rotor Induction MachinesThree-phase wound-rotor induction machine starting current and torque versus the rotor resistance 7KUHH SKDVH ZRXQG URWRU LQGXFWLRQ PDFKLQHV

© Festo Didactic 86367-10 III

Safety and Common Symbols

Caution, risk of danger

Page 4: Three-Phase Wound-Rotor Induction MachinesThree-phase wound-rotor induction machine starting current and torque versus the rotor resistance 7KUHH SKDVH ZRXQG URWRU LQGXFWLRQ PDFKLQHV

Safety and Common Symbols

IV © Festo Didactic 86367-10

Page 5: Three-Phase Wound-Rotor Induction MachinesThree-phase wound-rotor induction machine starting current and torque versus the rotor resistance 7KUHH SKDVH ZRXQG URWRU LQGXFWLRQ PDFKLQHV

© Festo Didactic 86367-10 V

Table of Contents

Page 6: Three-Phase Wound-Rotor Induction MachinesThree-phase wound-rotor induction machine starting current and torque versus the rotor resistance 7KUHH SKDVH ZRXQG URWRU LQGXFWLRQ PDFKLQHV

Table of Contents

VI © Festo Didactic 86367-10

Page 7: Three-Phase Wound-Rotor Induction MachinesThree-phase wound-rotor induction machine starting current and torque versus the rotor resistance 7KUHH SKDVH ZRXQG URWRU LQGXFWLRQ PDFKLQHV

© Festo Didactic 86367-10 VII

Preface

Page 8: Three-Phase Wound-Rotor Induction MachinesThree-phase wound-rotor induction machine starting current and torque versus the rotor resistance 7KUHH SKDVH ZRXQG URWRU LQGXFWLRQ PDFKLQHV

Preface

VIII © Festo Didactic 86367-10

Page 9: Three-Phase Wound-Rotor Induction MachinesThree-phase wound-rotor induction machine starting current and torque versus the rotor resistance 7KUHH SKDVH ZRXQG URWRU LQGXFWLRQ PDFKLQHV

© Festo Didactic 86367-10 IX

About This Manual

Page 10: Three-Phase Wound-Rotor Induction MachinesThree-phase wound-rotor induction machine starting current and torque versus the rotor resistance 7KUHH SKDVH ZRXQG URWRU LQGXFWLRQ PDFKLQHV

About This Manual

X © Festo Didactic 86367-10

Safety considerations

Prerequisite

DC Power Circuits Single-Phase AC Power CircuitsThree-Phase AC Power Circuits Three-Phase Rotating Machines

Systems of units

Page 11: Three-Phase Wound-Rotor Induction MachinesThree-phase wound-rotor induction machine starting current and torque versus the rotor resistance 7KUHH SKDVH ZRXQG URWRU LQGXFWLRQ PDFKLQHV

© Festo Didactic 86367-10 XI

To the Instructor

Accuracy of measurements

Equipment installation

Page 12: Three-Phase Wound-Rotor Induction MachinesThree-phase wound-rotor induction machine starting current and torque versus the rotor resistance 7KUHH SKDVH ZRXQG URWRU LQGXFWLRQ PDFKLQHV
Page 13: Three-Phase Wound-Rotor Induction MachinesThree-phase wound-rotor induction machine starting current and torque versus the rotor resistance 7KUHH SKDVH ZRXQG URWRU LQGXFWLRQ PDFKLQHV

Sample Exercise

Extracted from

the Student Manual

and the Instructor Guide

Page 14: Three-Phase Wound-Rotor Induction MachinesThree-phase wound-rotor induction machine starting current and torque versus the rotor resistance 7KUHH SKDVH ZRXQG URWRU LQGXFWLRQ PDFKLQHV
Page 15: Three-Phase Wound-Rotor Induction MachinesThree-phase wound-rotor induction machine starting current and torque versus the rotor resistance 7KUHH SKDVH ZRXQG URWRU LQGXFWLRQ PDFKLQHV

© Festo Didactic 86367-10 21

Three-phase wound-rotor induction machine starting current and torque versus the rotor resistance

Three-Phase Wound-Rotor Induction Machine with Rotor Resistance

Exercise 2

EXERCISE OBJECTIVE

DISCUSSION OUTLINE

DISCUSSION

Page 16: Three-Phase Wound-Rotor Induction MachinesThree-phase wound-rotor induction machine starting current and torque versus the rotor resistance 7KUHH SKDVH ZRXQG URWRU LQGXFWLRQ PDFKLQHV

Exercise 2 – Three-Phase Wound-Rotor Induction Machine with Rotor Resistance Discussion

22 © Festo Didactic 86367-10

Three-phase wound-rotor induction machine starting current

Page 17: Three-Phase Wound-Rotor Induction MachinesThree-phase wound-rotor induction machine starting current and torque versus the rotor resistance 7KUHH SKDVH ZRXQG URWRU LQGXFWLRQ PDFKLQHV

Exercise 2 – Three-Phase Wound-Rotor Induction Machine with Rotor Resistance Discussion

© Festo Didactic 86367-10 23

Three-phase wound-rotor induction machine starting torque

Page 18: Three-Phase Wound-Rotor Induction MachinesThree-phase wound-rotor induction machine starting current and torque versus the rotor resistance 7KUHH SKDVH ZRXQG URWRU LQGXFWLRQ PDFKLQHV

Exercise 2 – Three-Phase Wound-Rotor Induction Machine with Rotor Resistance Discussion

24 © Festo Didactic 86367-10

Varying the speed of a three-phase wound-rotor induction machine through the rotor resistance

Page 19: Three-Phase Wound-Rotor Induction MachinesThree-phase wound-rotor induction machine starting current and torque versus the rotor resistance 7KUHH SKDVH ZRXQG URWRU LQGXFWLRQ PDFKLQHV

Exercise 2 – Three-Phase Wound-Rotor Induction Machine with Rotor Resistance Discussion

© Festo Didactic 86367-10 25

Page 20: Three-Phase Wound-Rotor Induction MachinesThree-phase wound-rotor induction machine starting current and torque versus the rotor resistance 7KUHH SKDVH ZRXQG URWRU LQGXFWLRQ PDFKLQHV

Exercise 2 – Three-Phase Wound-Rotor Induction Machine with Rotor Resistance Discussion

26 © Festo Didactic 86367-10

Page 21: Three-Phase Wound-Rotor Induction MachinesThree-phase wound-rotor induction machine starting current and torque versus the rotor resistance 7KUHH SKDVH ZRXQG URWRU LQGXFWLRQ PDFKLQHV

Exercise 2 – Three-Phase Wound-Rotor Induction Machine with Rotor Resistance Procedure Outline

© Festo Didactic 86367-10 27

Set up and connections

In this section, you will set up a circuit containing a three-phase wound-rotor induction machine coupled to a prime mover/brake. You will then set the measuring equipment required to study the three-phase wound-rotor induction machine operation when the rotor windings are interconnected through resistors.

a Appendix E shows how to replace the pulley installed on the shaft of a supplied machine.

a Make sure you use the same Four-Quadrant Dynamometer/Power Supply module as in Exercise 1 of this manual by confirming that the module’s serial number is the same as the serial number you recorded in the first step of Exercise 1.

Power Input

Power Input

PROCEDURE OUTLINE

PROCEDURE

Page 22: Three-Phase Wound-Rotor Induction MachinesThree-phase wound-rotor induction machine starting current and torque versus the rotor resistance 7KUHH SKDVH ZRXQG URWRU LQGXFWLRQ PDFKLQHV

Exercise 2 – Three-Phase Wound-Rotor Induction Machine with Rotor Resistance Procedure

28 © Festo Didactic 86367-10

a The values of certain components used in the circuits of this manual depend on your local ac power network voltage and frequency. Whenever necessary, a table below the circuit diagram indicates the value of each component for ac power network voltages of 120 V, 220 V, and 240 V, and for ac power network frequencies of 50 Hz and 60 Hz. Make sure to use the component values corresponding to your local ac power network voltage and frequency.

a Appendix C lists the switch settings required on the Resistive Load in order to obtain various resistance values.

Page 23: Three-Phase Wound-Rotor Induction MachinesThree-phase wound-rotor induction machine starting current and torque versus the rotor resistance 7KUHH SKDVH ZRXQG URWRU LQGXFWLRQ PDFKLQHV

Exercise 2 – Three-Phase Wound-Rotor Induction Machine with Rotor Resistance Procedure

© Festo Didactic 86367-10 29

Operating Mode Dynamometer

Computer-Based Instrumentation

OK

Range I1 I2 High

Function Speed Sweep

Start Speed

a The synchronous speed of the Three-Phase Wound-Rotor Induction Machine is 1500 r/min at a local ac power network frequency of 50 Hz and 1800 r/min at a local ac power network frequency of 60 Hz.

Finish Speed

Number of Steps

Step Duration

Record Data to Table Yes

Pulley Ratio

I1

PQS1 PQS2E1 I1 E2 I2

Page 24: Three-Phase Wound-Rotor Induction MachinesThree-phase wound-rotor induction machine starting current and torque versus the rotor resistance 7KUHH SKDVH ZRXQG URWRU LQGXFWLRQ PDFKLQHV

Exercise 2 – Three-Phase Wound-Rotor Induction Machine with Rotor Resistance Procedure

30 © Festo Didactic 86367-10

I1

Effect of the rotor resistance on the operation of a three-phase wound-rotor induction machine

In this section, you will make the three-phase wound-rotor induction machine speed decrease by step from 100 r/min above the machine synchronous speed to 0 r/min, recording at each step in the Data Table the machine speed, torque, mechanical power, line current, active power, reactive power, and power factor. You will calculate the machine efficiency using the recorded machine mechanical power and active power values. On the same graph, you will plot the torque versus speed curve when the rotor is short-circuited (using the results you obtained in the previous exercise), as well as when resistance is added to the rotor, and interpret the results. Finally, you will plot on the same graph the efficiency versus mechanical power curve when the rotor is short-circuited (using the results you obtained in the previous exercise), as well as when resistance is added to the rotor, and interpret the results.

a The Three-Phase Wound-Rotor Induction Machine is fitted with an overvoltage protection circuit preventing the rotor voltage from reaching values that could damage the machine rotor windings. If the overvoltage protection trips when performing the manipulation above, turn the three-phase ac power source off, wait a few seconds, and turn the three-phase ac power on while pressing and holding the push-button on the Three-Phase Wound-Rotor Induction Machine.

Speed Sweep

Page 25: Three-Phase Wound-Rotor Induction MachinesThree-phase wound-rotor induction machine starting current and torque versus the rotor resistance 7KUHH SKDVH ZRXQG URWRU LQGXFWLRQ PDFKLQHV

Exercise 2 – Three-Phase Wound-Rotor Induction Machine with Rotor Resistance Procedure

© Festo Didactic 86367-10 31

Speed Sweep

Speed Sweep

Start SpeedFinish Speed

Finish Speed

Number of Steps

Step Duration

Record Data to Table Yes

Pulley Ratio

Speed Sweep Speed Sweep

a If the overvoltage protection trips at the end of the speed sweep performed above (i.e., when the speed of the three-phase wound-rotor induction machine approaches 0 r/min), stop the function, turn the three-phase ac source power source off, delete the data recorded to the Data Table during this speed sweep, turn the three-phase ac power source on, and start the

function again. This time, however, press and hold the push-button on the Three-Phase Wound-Rotor Induction

Machine as soon as the speed decreases below 200 r/min. Release the push-button once the speed sweep is completed.

Page 26: Three-Phase Wound-Rotor Induction MachinesThree-phase wound-rotor induction machine starting current and torque versus the rotor resistance 7KUHH SKDVH ZRXQG URWRU LQGXFWLRQ PDFKLQHV

Exercise 2 – Three-Phase Wound-Rotor Induction Machine with Rotor Resistance Procedure

32 © Festo Didactic 86367-10

a The machine torque recorded when the machine speed is equal to 0 r/min is slightly underestimated due to the way friction compensation is implemented in the Four-Quadrant Dynamometer/Power Supply.

a Do not calculate the machine efficiency when the machine mechanical power is lower than about 50 W (positive or negative).

Page 27: Three-Phase Wound-Rotor Induction MachinesThree-phase wound-rotor induction machine starting current and torque versus the rotor resistance 7KUHH SKDVH ZRXQG URWRU LQGXFWLRQ PDFKLQHV

Exercise 2 – Three-Phase Wound-Rotor Induction Machine with Rotor Resistance Procedure

© Festo Didactic 86367-10 33

Page 28: Three-Phase Wound-Rotor Induction MachinesThree-phase wound-rotor induction machine starting current and torque versus the rotor resistance 7KUHH SKDVH ZRXQG URWRU LQGXFWLRQ PDFKLQHV

Exercise 2 – Three-Phase Wound-Rotor Induction Machine with Rotor Resistance Procedure

34 © Festo Didactic 86367-10

2.5

2.0

1.5

1.0

0.5

0.0

0.5

1.0

1.5

2.0

2.5

3.0

3.5

4.0

0 500 1000 1500 2000

Page 29: Three-Phase Wound-Rotor Induction MachinesThree-phase wound-rotor induction machine starting current and torque versus the rotor resistance 7KUHH SKDVH ZRXQG URWRU LQGXFWLRQ PDFKLQHV

Exercise 2 – Three-Phase Wound-Rotor Induction Machine with Rotor Resistance Procedure

© Festo Didactic 86367-10 35

20

15

10

5

0

5

10

15

20

25

30

35

40

0 500 1000 1500 2000

Page 30: Three-Phase Wound-Rotor Induction MachinesThree-phase wound-rotor induction machine starting current and torque versus the rotor resistance 7KUHH SKDVH ZRXQG URWRU LQGXFWLRQ PDFKLQHV

Exercise 2 – Three-Phase Wound-Rotor Induction Machine with Rotor Resistance Procedure

36 © Festo Didactic 86367-10

Page 31: Three-Phase Wound-Rotor Induction MachinesThree-phase wound-rotor induction machine starting current and torque versus the rotor resistance 7KUHH SKDVH ZRXQG URWRU LQGXFWLRQ PDFKLQHV

Exercise 2 – Three-Phase Wound-Rotor Induction Machine with Rotor Resistance Conclusion

© Festo Didactic 86367-10 37

a Appendix E shows how to replace the pulley installed on the shaft of a supplied machine.

0

10

20

30

40

50

60

70

80

90

100

0 50 100 150 200 250 300 350 400 450 500 550

CONCLUSION

Page 32: Three-Phase Wound-Rotor Induction MachinesThree-phase wound-rotor induction machine starting current and torque versus the rotor resistance 7KUHH SKDVH ZRXQG URWRU LQGXFWLRQ PDFKLQHV

Exercise 2 – Three-Phase Wound-Rotor Induction Machine with Rotor Resistance Review Questions

38 © Festo Didactic 86367-10

REVIEW QUESTIONS

Page 33: Three-Phase Wound-Rotor Induction MachinesThree-phase wound-rotor induction machine starting current and torque versus the rotor resistance 7KUHH SKDVH ZRXQG URWRU LQGXFWLRQ PDFKLQHV

© Festo Didactic 86367-10 57

Bibliography

Electrical Machines, Drives, and Power Systems