INSULATION INSPECTION DEVICE FOR MOTORS AND INSULATION INSPECTION METHOD FOR MOTORS

• US 20150247901A1
• Filed: 04/17/2013
• Published: 09/03/2015
• Est. Priority Date: 11/29/2012
• Status: Active Grant

• Current Assignee: Mitsubishi Electric Corporation
• Original Assignee: Mitsubishi Electric Corporation
• Inventors: Muto, Hirotaka, Okada, Shinichi, Shiota, Hiroki
• Granted Patent: US 9,797,955 B2
• Time in Patent Office: Days
• US Class Current: 1/1
• CPC Class Codes: G01R 31/12 Testing dielectric strength or breakdown voltage ; Testing or monitoring effectiveness or level of insulation, e.g. of a cable or of an apparatus, for example using partial discharge measurements; Electrostatic testing G01R31/08, G01R31/327 and G01R31/72 take precedence; measuring in plasmas G01R19/0061; measuring dielectric constants G01R27/2617; ESD, EMC or EMP testing of circuits G01R31/002
• CPC Class Codes: G01R 31/1272 of cable, line or wire insulation, e.g. using partial discharge measurements locating faults in cables G01R31/083
• CPC Class Codes: G01R 31/34 Testing dynamo-electric machines
• CPC Class Codes: G01R 31/343 in operation
• CPC Class Codes: H02P 29/0241 the fault being an overvoltage

Abstract

An insulation inspection device for motors includes an inverter for driving a motor, a partial discharge detecting unit for determining soundness of the motor, and a control circuit for controlling the inverter. The control circuit adjusts a switching interval of a voltage pulse of the inverter so as to be equal to a pulse round-trip propagation time between the inverter and the motor, thereby generating surge voltage higher than driving voltage for the motor, between the motor and ground, and adjusts a switching time for each phase of the inverter, thereby generating surge voltage higher than driving voltage for the motor, between phases, thus performing insulation inspection.

Claims

1-11. -11. (canceled)

12. An insulation inspection device for motors comprising:

an inverter for driving a motor;

a partial discharge detecting unit for detecting partial discharge in the motor and determining soundness of the motor; and

a control circuit for controlling the inverter, wherein

the control circuit controls the inverter to adjust a switching interval of a voltage pulse so as to be equal to or smaller than a pulse round-trip propagation time between the inverter and the motor, thereby generating surge voltage equal to or lower than three times and equal to or higher than two times driving voltage for the motor, between the motor and ground.

13. The insulation inspection device for motors according to claim 12, wherein the control circuit includes a circuit for adjusting a rising time of the voltage pulse of output of the inverter, and adjusts the rising time of the voltage pulse, thereby generating surge voltage higher than the driving voltage for the motor.

14. The insulation inspection device for motors according to claim 12, further comprising an insulation inspection setting unit for storing data of the driving voltage for the motor, the pulse round-trip propagation time between the inverter and the motor, and an inspection procedure, and for, at a time of insulation inspection, reading the stored data and performing the insulation inspection using specified test voltage.

15. The insulation inspection device for motors according to claim 12, wherein the partial discharge detecting unit includes an antenna for detecting a partial discharge signal from an electromagnetic wave radiated from the motor.

16. The insulation inspection device for motors according to claim 12, wherein the partial discharge detecting unit includes a current sensor for detecting a partial discharge signal from partial discharge current of the motor.

17. The insulation inspection device for motors according to claim 12, wherein the inverter is a dedicated inverter for motor insulation inspection.

18. An insulation inspection device for motors comprising:

an inverter for driving a motor;

a partial discharge detecting unit for detecting partial discharge in the motor and determining soundness of the motor; and

a control circuit for controlling the inverter, wherein

the control circuit further adjusts a switching time for each phase of the inverter so that the switching times are simultaneous or shifted from each other, thereby generating surge voltage equal to or lower than three times and equal to or higher than two times driving voltage for the motor, between phases of the motor.

19. The insulation inspection device for motors according to claim 18, wherein the control circuit includes a circuit for adjusting a rising time of the voltage pulse of output of the inverter, and adjusts the rising time of the voltage pulse, thereby generating surge voltage higher than the driving voltage for the motor.

20. The insulation inspection device for motors according to claim 18, further comprising an insulation inspection setting unit for storing data of the driving voltage for the motor, the pulse round-trip propagation time between the inverter and the motor, and an inspection procedure, and for, at a time of insulation inspection, reading the stored data and performing the insulation inspection using specified test voltage.

21. The insulation inspection device for motors according to claim 18, wherein the partial discharge detecting unit includes an antenna for detecting a partial discharge signal from an electromagnetic wave radiated from the motor.

22. The insulation inspection device for motors according to claim 18, wherein the inverter is a dedicated inverter for motor insulation inspection.

23. An insulation inspection device for motors comprising:

an inverter for driving a motor;

a partial discharge detecting unit for detecting partial discharge in the motor and determining soundness of the motor; and

a control circuit for controlling the inverter,

wherein

the control circuit adjusts the switching interval of the voltage pulse for each phase of the inverter so as to be equal to or smaller than the pulse round-trip propagation time, and reverses positive and negative polarities of the voltage pulses between the phases, thereby generating surge voltage equal to or lower than five times and equal to or higher than two times driving voltage for the motor, between the phases of the motor.

24. The insulation inspection device for motors according to claim 23, wherein the control circuit includes a circuit for adjusting a rising time of the voltage pulse of output of the inverter, and adjusts the rising time of the voltage pulse, thereby generating surge voltage higher than the driving voltage for the motor.

25. The insulation inspection device for motors according to claim 23, further comprising an insulation inspection setting unit for storing data of the driving voltage for the motor, the pulse round-trip propagation time between the inverter and the motor, and an inspection procedure, and for, at a time of insulation inspection, reading the stored data and performing the insulation inspection using specified test voltage.

26. The insulation inspection device for motors according to claim 23, wherein the partial discharge detecting unit includes a current sensor for detecting a partial discharge signal from partial discharge current of the motor.

27. The insulation inspection device for motors according to claim 23, wherein the inverter is a dedicated inverter for motor insulation inspection.

28. An insulation inspection method for motors, using an insulation inspection device for motors including an inverter for driving a motor, a partial discharge detecting unit for determining soundness of the motor, and a control circuit for controlling the inverter, the insulation inspection method comprising:

a first step of setting a value of test voltage to be applied to the motor;

a second step of the control circuit adjusting a switching interval of a voltage pulse of the inverter so as to be equal to or smaller than a pulse round-trip propagation time between the inverter and the motor, in order to set, to the test voltage, surge voltage that is to be generated between the motor and ground and is equal to or lower than three times and equal to or higher than two times driving voltage for the motor;

a third step of the inverter applying the test voltage between each phase and ground; and

a fourth step of the partial discharge detecting unit detecting a partial discharge signal and determining soundness of the motor with respect to ground.

29. The insulation inspection method for motors according to claim 28, using the insulation inspection device for motors in which the inverter is a dedicated inverter for motor insulation inspection.

30. An insulation inspection method for motors, using an insulation inspection device for motors including an inverter for driving a motor, a partial discharge detecting unit for determining soundness of the motor, and a control circuit for controlling the inverter, the insulation inspection method comprising:

a first step of setting a value of test voltage to be applied to the motor;

a fifth step of the control circuit adjusting a switching time for each phase of the inverter so that the switching times are simultaneous or shifted from each other in order to set, to the test voltage, surge voltage that is to be generated between phases of the motor and is equal to or lower than three times and equal to or higher than two times driving voltage for the motor;

a sixth step of the inverter applying the test voltage between the phases, and

a seventh step of the partial discharge detecting unit detecting a partial discharge signal and determining phase-to-phase soundness of the motor.

31. The insulation inspection method for motors according to claim 30, using the insulation inspection device for motors in which the inverter is a dedicated inverter for motor insulation inspection.