System and method for monitoring the status of one or more components of an electrical machine

Patent metadata

Field	Value
Publication number	US-11211757-B2
Application number	US-201916592269-A
Country	US
Kind code	B2
Filing date	Oct 3, 2019
Priority date	Oct 4, 2018
Publication date	Dec 28, 2021
Grant date	Dec 28, 2021

Abstract

A system for monitoring the wear state of a carbon brush of a brush holder assembly in which the length of the carbon brush is diminished from an initial length as an end of the carbon brush wears away during use. The system includes a wear state monitor, including a sensor, coupled to the carbon brush. The wear state monitor is configured to rotate as the length of the carbon brush diminishes. The sensor is configured to measure an angular displacement of the wear state monitor as the wear state monitor rotates. The measured angular displacement of the wear state monitor correlates to an amount of diminution in the length of the carbon brush.

First claim

What is claimed is:

1. A system for monitoring the wear state of a carbon brush, comprising:
a brush holder assembly, the brush holder assembly including:
a carbon brush including a first end, a second end opposite the first end,

and a length measured from the first end to the second end, wherein the length is diminished from an initial length as the first end of the carbon brush wears away during use;
a wear state monitor coupled to the carbon brush, the wear state monitor including a sensor;

wherein the wear state monitor is configured to rotate as the length of the carbon brush diminishes;
wherein the sensor is configured to measure an angular displacement of the wear state monitor as the wear state monitor rotates;
wherein the measured angular displacement of the wear state monitor correlates to an amount of diminution in the length of the carbon brush.

2. The system of claim 1 , further comprising a spring having a first end and a second end, the first end coupled to the wear state monitor, wherein the spring is configured to provide a force urging the carbon brush into contact with a rotating conductive surface of an electrical machine.

3. The system of claim 2 , wherein the wear state monitor includes a circumferential groove extending around a circumferential outer surface of the wear state monitor, and wherein the spring is disposed within the groove.

4. The system of claim 2 , wherein a coiled portion of the spring is configured to wrap around a circumferential outer surface of the wear state monitor as the wear state monitor rotates.

5. The system of claim 1 , further comprising a spring having a coiled portion and an elongate portion extending from the coiled portion, wherein the wear state monitor is positioned within the coiled portion.

6. The system of claim 5 , wherein the wear state monitor includes a circumferential groove extending around a circumferential outer surface of the wear state monitor, and wherein the coiled portion of the spring is disposed within the groove.

7. The system of claim 5 , further comprising a spacer positioned between the coiled portion of the spring and the second end of the carbon brush.

8. The system of claim 7 , wherein the spacer includes a magnet, and the sensor is a Hall effect sensor sensing a magnetic field of the magnet.

9. The system of claim 7 , wherein the spacer defines a concave cradle, wherein the coiled portion of the spring rests in the cradle.

10. The system of claim 1 , wherein the wear state monitor rotates about an axis of rotation, wherein the axis of rotation is a fixed distance from the second end of the carbon brush as the wear state monitor rotates.

11. The system of claim 1 , wherein the sensor is a rotary magnetic encoder.

12. The system of claim 1 , wherein the sensor is configured to transmit a wireless signal to a site monitor, and wherein the wireless signal is configured to provide information relating to diminution in length of the carbon brush.

13. A system for monitoring the wear state of a carbon brush, comprising:
a brush holder coupled to a handle, the brush holder including an opening;
a carbon brush disposed within the opening of the brush holder,
a spring applying a force against the carbon brush to translate the carbon brush within the opening as a first end of the carbon brush wears away during use; and
a wear state monitor positioned within a coiled portion of the spring, the wear state monitor configured to rotate as the first end of the carbon brush wears away.

14. The system of claim 13 , further comprising a sensor disposed within a housing of the wear state monitor, wherein the sensor is configured to measure an angular displacement of the wear state monitor as the wear state monitor rotates.

15. The system of claim 14 , wherein the measured angular displacement of the wear state monitor correlates to an amount the carbon brush has worn away.

16. The system of claim 13 , wherein the wear state monitor rotates about an axis of rotation, wherein the axis of rotation is a fixed distance from an upper surface of the carbon brush as the wear state monitor rotates.

17. The system of claim 13 , wherein the spring includes an elongate portion extending from the coiled portion of the spring along a side surface of the carbon brush.

18. The system of claim 17 , wherein an end of the elongate portion of the spring is removably coupled to the brush holder.

19. The system of claim 13 , wherein the wear state monitor includes a circumferential groove extending around a circumferential outer surface of the wear state monitor, and wherein the coiled portion of the spring is disposed within the groove.

20. The system of claim 13 , wherein a portion of the spring is configured to wind up around a circumferential outer surface of the wear state monitor as the wear state monitor rotates.

21. The system of claim 13 , wherein the wear state monitor is configured to rotate through an arc angle as the carbon brush wears away, and wherein the arc angle correlates to the amount the carbon brush wears away.

22. A method for monitoring the wear state of a carbon brush, the method comprising:
determining an angular displacement of a wear state monitor positioned adjacent to the carbon brush with a sensor as the wear state monitor rotates as a length of the carbon brush diminishes during use; and
determining a wear state of the carbon brush based on the angular displacement of the wear state monitor.

23. The method of claim 22 , further comprising:
comparing the wear state of the carbon brush to a threshold value.

24. The method of claim 22 , further comprising:
communicating an indication of the wear state of the carbon brush to a user.

Assignees

• Cutsforth Inc

Inventors

• Cutsforth Robert S
• Cutsforth Dustin L
• Bruey Douglas Christopher
• Schaaf Michael Lee
• Harrison David William Drury

Classifications

• H01R39/26

  Solid sliding contacts, e.g. carbon brush · CPC title

• H01R39/58 Primary

  Means structurally associated with the current collector for indicating condition thereof, e.g. for indicating brush wear · CPC title

• H02K11/20

  for measuring, monitoring, testing, protecting or switching (rectifiers H02K11/04; power electronics H02K11/33) · CPC title

• G01B21/22

  for measuring angles or tapers; for testing the alignment of axes · CPC title

• H01R39/38

  Brush holders · CPC title