System and method for testing winding insulation resistance

• US 20090251154A1
• Filed: 04/02/2008
• Published: 10/08/2009
• Est. Priority Date: 04/02/2008
• Status: Active Grant

• Current Assignee: Caterpillar Incorporated
• Original Assignee: Caterpillar Incorporated
• Inventors: Lindsey, Robert Wayne
• Granted Patent: US 8,093,906 B2
• Time in Patent Office: Days
• US Class Current: 324/551
• CPC Class Codes: G01R 31/1227 of components, parts or materials G01R31/1209, G01R31/1218, G01R31/18 take precedence; circuits therefor G01R31/14; testing vessels of electrodes G01R31/16
• CPC Class Codes: G01R 31/34 Testing dynamo-electric machines
• CPC Class Codes: G01R 31/346 Testing of armature or field windings

Abstract

A power electronics system configured to determine a condition of a winding insulation is disclosed. The system may include at least one capacitor, and a first resistance coupled to the at least one capacitor. The system may further include a plurality of electronic switching devices coupled to at least the first resistance and the at least one capacitor, wherein the plurality of electronic switching devices are configured to selectively couple the at least one capacitor to a power source to charge the at least one capacitor during a first time interval and selectively couple the at least one capacitor to a second resistance during a second time interval. The system may further include a voltage measuring device configured to detect a change in voltage at a terminal of the at least one capacitor in response to the selective coupling of the at least one capacitor to the second resistance. The system may further include a computing system configured to determine a condition of the insulation based on the detection.

Claims

1. A system comprising:

at least one capacitor;

a first resistance coupled to the at least one capacitor;

a plurality of electronic switching devices coupled to at least the first resistance and the at least one capacitor, wherein the plurality of electronic switching devices are configured to;

selectively couple the at least one capacitor to a power source to charge the at least one capacitor during a first time interval; and

selectively couple the at least one capacitor to a second resistance during a second time interval;

a voltage measuring device configured to detect a change in voltage at a terminal of the at least one capacitor in response to the selective coupling of the at least one capacitor to the second resistance; and

a computing system configured to determine a condition of the winding insulation based on the detection.

2. The system of claim 1, wherein the change in voltage detected by the voltage measuring device is a substantially instantaneous change in voltage.

3. The system of claim 2, wherein a first resistance value associated with the first resistance, and a capacitance associated with the at least one capacitor substantially define a first discharge rate of the at least one capacitor.

4. The system of claim 3, wherein the second resistance corresponds to a resistance of either a winding insulation associated with a motor or a winding insulation associated with a generator.

5. The system of claim 4, wherein the computing system is further configured to generate an alarm indicative of the substantially instantaneous change in voltage.

6. The system of claim 4, wherein the computing system is further configured to calculate a resistance value associated with the second resistance.

7. The system of claim 6, wherein the computing system is further configured to compare the resistance value associated with the second resistance to a threshold resistance value and, identify, based on the comparison, a condition of the winding insulation.

8. The system of claim 7, wherein the computing system is further configured to generate an alarm in response to the identified condition of the winding insulation.

9. The system of claim 8, wherein the computing system is an electronic control module that is configured to at least control the power electronics module during normal operation.

10. A method for determining a condition of a winding insulation, the method comprising:

discharging at least one capacitor;

selectively coupling the at least one capacitor to a resistance while the at least one capacitor is discharging;

detecting a change in voltage at a terminal of the at least one capacitor in response to the coupling of the at least one capacitor to the resistance; and

determining, based on the detection, a condition of the winding insulation.

11. The method of claim 10, wherein the change in voltage is substantially instantaneous.

12. The method of claim 11, wherein the resistance includes at least the resistance of the winding insulation associated with a motor or a generator.

13. The method of claim 12, further including generating an alert, wherein the alert corresponds to the substantially instantaneous change in voltage.

14. The method of claim 10, further including:

determining a discharge rate of the at least one capacitor after the at least one capacitor is coupled to the resistance; and

using at least the discharge rate to substantially determine a resistance value associated with the at least one capacitor.

15. The method of claim 14, further including using at least the resistance value to determine if the winding insulation associated with a motor or a generator needs to be replaced.

16. The method of claim 15, further including generating an alert indicative of the resistance value.

17. A system configured to determine a condition of a winding insulation, the system comprising:

at least one capacitor;

a DC power producing device coupled to the at least one capacitor;

a first resistance coupled to the at least one capacitor;

a plurality of electronic switching devices coupled to at least the first resistance, and the at least one capacitor, wherein the plurality of electronic switching devices are configured to selectively couple the DC power producing device to a second resistance, resulting in a change in voltage at a terminal of the at least one capacitor; and

a computing system configured to determine a condition of the winding insulation based on the change in voltage.

18. The system of claim 17, wherein the second resistance corresponds to the resistance of the winding insulation associated with a motor or the resistance of the winding insulation associated with a generator.

19. The system of claim 18, wherein the change in voltage is substantially instantaneous.

20. The system of claim 19, wherein the computing system is configured to generate an alarm indicative of the substantially instantaneous change in voltage.