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

Patent metadata

Field	Value
Publication number	US-9252643-B2
Application number	US-201313802969-A
Country	US
Kind code	B2
Filing date	Mar 14, 2013
Priority date	Mar 14, 2013
Publication date	Feb 2, 2016
Grant date	Feb 2, 2016

Abstract

A monitoring apparatus configured for monitoring a carbon brush of a brush holder assembly of an electrical machine. The monitoring apparatus may include a flexible sensor and a signal processing circuit for processing a signal received from the flexible sensor. The flexible sensor may have an electrical resistance that varies based on a radius of curvature of the flexible sensor, wherein the radius of curvature of the flexible sensor may be associated with a deflection of a spring providing a force to engage the carbon brush with a rotating component of the electrical machine. The signal processing circuit may be coupled to the sensor and may be configured to determine a measure of a wear state of the carbon brush using information about the variable resistance of the flexible sensor.

First claim

What is claimed is:

1. A monitoring apparatus for monitoring a carbon brush of a brush holder assembly of an electrical machine, the apparatus comprising:
a flexible sensor having an electrical resistance that varies based on a radius of curvature of the flexible sensor, wherein the radius of curvature of the flexible sensor is associated with a deflection of a spring providing a force to engage the carbon brush with a rotating component of the electrical machine;
a signal processing circuit coupled to the sensor, the signal processing circuit for determining a measure of a wear state of the carbon brush using information about the variable resistance of the flexible sensor.

2. The monitoring apparatus of claim 1 , further comprising a user interface for providing an indication of the measure of the wear state of the carbon brush to a user.

3. The monitoring apparatus of claim 2 , wherein the user interface includes at least one light emitting diode (LED).

4. The monitoring apparatus of claim 3 , wherein the one or more light emitting diodes (LED) are configured to emit light of a first color when the signal processing circuit determines a first wear state of the carbon brush and to emit light of a second color when the signal processing circuit determines a second wear state of the carbon brush.

5. The monitoring apparatus of claim 4 , wherein the first wear state of the carbon brush corresponds to a replacement wear state, and the second wear state of the carbon brush corresponds to a wear state approaching the replacement wear state.

6. The monitoring apparatus of claim 1 , wherein the signal processing circuit determines the measure of the wear state of the carbon brush by comparing the variable resistance of the flexible sensor to at least one predetermined threshold value.

7. The monitoring apparatus of claim 6 , wherein the at least one predetermined threshold value corresponds to a steady state measure of the electrical resistance of the flexible sensor.

8. The monitoring apparatus of claim 1 , wherein the signal processing circuit determines the measure of the wear state of the carbon brush by comparing the variable resistance of the flexible sensor to a first threshold value and determines a measure of a wear state of the rotating component of the electrical machine by comparing the variable resistance of the flexible sensor to a second threshold value.

9. The monitoring apparatus of claim 8 , wherein the first threshold value corresponds to a steady state measure of the variable resistance of the flexible sensor, and the second threshold value corresponds to a transient measure of the variable resistance of the flexible sensor.

10. The monitoring apparatus of claim 1 , wherein the signal processing circuit is configured to determine a wear state of the rotating component of the electrical machine using a measure of vibration of the carbon brush using information about the variable resistance of the flexible sensor, wherein the rotating component is a slip ring or a commutator.

11. The monitoring apparatus of claim 1 , further comprising a communication circuit coupled to the signal processing circuit, the communication circuit for communicating the measure of the wear state of the carbon brush to a site monitor capable of receiving information about the wear states of one or more carbon brushes of one or more brush holder assemblies associated with the electrical machine.

12. The monitoring apparatus of claim 11 , wherein the wear state of the carbon brush is communicated to a central monitoring device, wherein the central monitoring device is located at a geographical location different than the geographical location of the electrical machine.

13. The monitoring apparatus of claim 11 , wherein the wear state of the carbon brush is further communicated to a user via a voice message, a text message, an instant message, an email, an audible indication, and/or a visual indication.

14. The monitoring apparatus of claim 1 , further comprising one or more environmental sensors, wherein the environmental sensors include at least one of a temperature sensor or a humidity sensor.

15. The monitoring apparatus of claim 1 , wherein the monitoring apparatus is positioned adjacent to the spring of the brush holder assembly.

16. The monitoring apparatus of claim 15 , wherein the flexible sensor is affixed to the spring.

17. A system for monitoring a wear state of one or more carbon brushes of an electrical machine, the system comprising:
one or more brush holder assemblies associated with the electrical machine, wherein each brush holder assembly includes:
a carbon brush;
a spring adjacent to the carbon brush, the spring for providing a force to the carbon brush such that the carbon brush engages a rotating component of the electrical machine;
a flexible sensor positioned adjacent to the spring, the flexible sensor having an electrical resistance that varies based on a radius of curvature of the flexible sensor, wherein the radius of curvature is representative of a physical position and/or movement of the carbon brush;
a wear state monitor coupled to the flexible sensor, the wear state monitor for determining a measure of a wear state of the carbon brush using the variable resistance of the flexible sensor; and
a site monitor communicatively coupled with the wear state monitor of the one or more brush assemblies, the site monitor capable of receiving wear state information about the carbon brushes of the one or more brush assemblies and communicating the wear state of the one or more carbon brushes to a user.

18. The system of claim 17 , wherein the wear state monitor includes a user interface having one or more light emitting diodes (LEDs) for communicating information about the wear state of the carbon brush to a user.

19. The system of claim 18 , wherein a first wear state of the carbon brush is associated with a first color of the LEDs and a second wear state of the carbon brush is associated with a second wear state of the carbon brush.

20. The system of claim 19 , wherein the first wear state corresponds to a wear state indicating that the carbon brush is to be replaced and the second wear state corresponds to a wear state before the carbon brush requires replacement.

21. The system of claim 17 , wherein the wear state monitor is further configured to determine a wear state of the rotating component of the electrical machine using the variable resistance of the flexible sensor.

22. The monitoring system of claim 21 , wherein the wear state monitor uses a steady state measure of the variable resistance of the flexible sensor to determine the wear state of the carbon brush and a transient measure of the variable resistance of the flexible sensor to determine the wear state of the rotating component, wherein the rotating component is a slip ring or a commutator.

23. The system of claim 22 , wherein the wear state monitor determines a first wear state of the rotating component by comparing the transient measure of the resistance of the flexible sensor to a first threshold value and determines a second wear state of the rotating component by comparing the transient measure of the resistance of the flexible sensor to a second threshold value.

24. The system of claim 23 , wherein the first wear state corresponds to a wear state indicating that the rotating component requires servicing and the second wear state corresponds to a wear state before th

Assignees

• Cutsforth Inc

Inventors

• Cutsforth Robert S

Classifications

• H02K11/001 Primary

  Electricity · mapped topic

• 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

• H01R39/381

  characterised by the application of pressure to brush · CPC title