System and Method for Detection of Motor Vibration

• US 20150288257A1
• Filed: 04/02/2014
• Published: 10/08/2015
• Est. Priority Date: 04/02/2014
• Status: Active Grant

• Current Assignee: Rockwell Automation Technologies Incorporated (Allen-Bradley Co., Inc.)
• Original Assignee: Rockwell Automation Technologies Incorporated (Allen-Bradley Co., Inc.)
• Inventors: Cooper, Mark, Bronk, Kelly J., Qian, Wei, Yuan, Zhenhuan, Sawant, Manas, Schmidt, Robert H., Ramanarayanan, Shankernarayan, Feng, Shun
• Granted Patent: US 9,673,685 B2
• Time in Patent Office: Days
• US Class Current: 1/1
• CPC Class Codes: G01M 1/14 Determining imbalance G01M1/30 takes precedence
• CPC Class Codes: H02K 11/20 for measuring, monitoring, testing, protecting or switching rectifiers H02K11/04; power electronics H02K11/33
• CPC Class Codes: H02K 5/24 specially adapted for suppression or reduction of noise or vibrations
• CPC Class Codes: H02P 21/14 Estimation or adaptation of machine parameters, e.g. flux, current or voltage

Abstract

An improved system for monitoring vibration of an electric machine is disclosed. According to one embodiment, sensors are positioned in a plane orthogonal to the motor shaft and each sensor detects vibration along at least one axis of the motor. The sensors are oriented such that the polarity of each sensor is reversed. The pairs of sensors may be used to isolate specific vibrations within the motor. According to another embodiment, a sensor may be mounted directly to the motor shaft. The sensor on the motor shaft directly detects vibrations along the motor shaft. Optionally, a second sensor may be mounted to a fixed location within the motor housing, and the combination of the sensor on the motor shaft and the sensor at a fixed location may be used to isolate specific vibrations within the motor. A motor controller may adjust operation of the motor to reduce the isolated vibration.

Claims

1. An electric machine configured to be operated by a controller, the electric machine comprising:

a housing;

a stator mounted within the housing and configured to receive a voltage from the controller to control operation of the electric machine;

a rotor rotatably mounted within the housing, wherein the rotor rotates as a function of the voltage applied to the stator;

a shaft connected to the rotor and extending outside the housing, the shaft having a central axis about which it rotates;

a first sensor mounted at a first position proximate to the shaft and configured to generate a signal corresponding to a vibration detected at the first position; and

a second sensor mounted at a second position proximate to the shaft and configured to generate a signal corresponding to a vibration detected at the second position, wherein the first position and the second position are located in a plane orthogonal to the central axis of the shaft, the signals corresponding to the vibration detected at the first and second positions are transmitted to the controller, and the controller adjusts operation of the electric machine as a function of the signals corresponding to the vibration detected at the first and second positions.

2. The electric machine of claim 1 wherein the vibration detected at the first position by the first sensor is in a first axis wherein the first axis has a first relationship to each of the plane and the central axis of the shaft and the vibration detected at the second position by the second sensor is in a second axis wherein the second axis has a second relationship to each of the plane and the central axis of the shaft and wherein the second relationship is substantially identical to the first relationship on a substantially opposite side of the shaft.

3. The electric machine of claim 1 wherein the signal generated by the first sensor has a positive magnitude and a negative magnitude and the signal generated by the second sensor has a positive magnitude and a negative magnitude, wherein the positive magnitude of the first sensor is in the same direction as the negative magnitude of the second sensor.

4. The electric machine of claim 1 wherein:

the first sensor generates a plurality of signals, each signal corresponding to a separate axis of the vibration detected at the first position,

the second sensor generates a plurality of signals, each signal corresponding to a separate axis of the vibration detected at the second position, and

each of the separate axes of the second sensor corresponds to one of the separate axes of the first sensor.

5. The electric machine of claim 4 wherein each of the plurality of signals generated by the first sensor has a positive magnitude and a negative magnitude and each of the plurality of signals generated by the second sensor has a positive magnitude and a negative magnitude, wherein the positive magnitude of each of the plurality of signals from the first sensor is in the same direction as the negative magnitude of each of the corresponding signals from the second sensor.

6. The electric machine of claim 1 further comprising:

a third sensor mounted at a third position proximate to the shaft and configured to generate a signal corresponding to a vibration detected at the third position; and

a fourth sensor mounted at a fourth position proximate to the shaft and configured to generate a signal corresponding to a vibration detected at the fourth position, wherein the third position and the fourth position are located in a plane orthogonal to the central axis of the shaft, the signals corresponding to the vibration detected at the third and fourth positions are transmitted to the controller, and the controller further adjusts operation of the electric machine as a function of the signals corresponding to the vibration detected at the third and fourth positions.

7. The electric machine of claim 1 wherein the first position is located on the shaft and the second position is a fixed mounting point.

8. An electric machine configured to be operated by a controller, the electric machine comprising:

a housing;

a stator mounted within the housing and configured to receive a voltage from the controller to control operation of the electric machine;

a rotor rotatably mounted within the housing, wherein the rotor rotates about a central axis as a function of the voltage applied to the stator;

at least one sensor mounted at a position proximate to the rotor, each sensor configured to generate a signal corresponding to a vibration detected at the position the sensor is mounted, wherein each position is located in a plane orthogonal to the central axis, each signal is transmitted to the controller, and the controller identifies the vibration as one of a rotational vibration, a radial unidirectional vibration, an axial directional vibration, a mechanical resonance, and a motor inclination as a function of the signals corresponding to the vibration detected.

9. The electric machine of claim 8 further comprising a shaft coupled to the rotor wherein one of the at least one sensors is mounted to the shaft.

10. The electric machine of claim 9 wherein one of the at least one sensors is mounted at a fixed location within the housing proximate to the shaft.

11. The electric machine of claim 8 wherein the at least one sensor includes a first sensor mounted at a first position and a second sensor mounted at a second position.

12. The electric machine of claim 11 further comprising at least one bearing set configured to rotatably mount the rotor within the housing wherein the first position and the second position are selected proximate to the bearing set.

13. The electric machine of claim 11 wherein:

the first sensor generates a plurality of signals, each signal corresponding to the vibration in a separate axis,

the second sensor generates a plurality of signals, each signal corresponding to the vibration in a separate axis, and

each of the separate axes of the second sensor corresponds to one of the separate axes of the first sensor.

14. The electric machine of claim 11 wherein the at least one sensor further includes a third sensor mounted at a third position and a fourth sensor mounted at a fourth position, wherein the third position and the fourth position are located in a plane orthogonal to the central axis of the shaft, each signal generated from the third and fourth sensor is transmitted to the controller, and the controller further adjusts operation of the electric machine as a function of the signals corresponding to the vibration detected at the third and fourth positions.

15. The electric machine of claim 8 wherein the controller adjusts operation of the electric machine as a function of the identified vibration.

16. A method of controlling operation of an electric machine, the method comprising the steps of:

generating a voltage with a controller, wherein the voltage is provided to a stator of the electric machine, which, in turn, causes rotation of a rotor of the electric machine;

detecting a vibration present at a first position within the electric machine with a first sensor mounted at the first position;

transmitting a signal corresponding to the vibration present at the first position from the first sensor to the controller;

detecting a vibration present at a second position within the electric machine with a second sensor mounted at the second position, wherein the first position and the second position are located in a plane orthogonal to a shaft of the electric machine and wherein the shaft is connected to the rotor;

transmitting a signal corresponding to the vibration present at the second position from the second sensor to the controller; and

adjusting operation of the electric machine with the controller as a function of the signals corresponding to the vibration present at the first and second positions.

17. The method of claim 16 wherein the signal generated by the first sensor has a positive magnitude and a negative magnitude and the signal generated by the second sensor has a positive magnitude and a negative magnitude, wherein the positive magnitude of the first sensor is in the same direction as the negative magnitude of the second sensor.

18. The method of claim 16 wherein:

the first sensor generates a plurality of signals, each signal corresponding to the vibration in a separate axis,

the second sensor generates a plurality of signals, each signal corresponding to the vibration in a separate axis, and

each of the separate axes of the second sensor corresponds to one of the separate axes of the first sensor.

19. The method of claim 18 wherein each of the plurality of signals generated by the first sensor has a positive magnitude and a negative magnitude and each of the plurality of signals generated by the second sensor corresponds has a positive magnitude and a negative magnitude, wherein the positive magnitude of each of the plurality of signals from the first sensor is in the same direction as the negative magnitude of each of the corresponding signals from the second sensor.

20. The method of claim 16 further comprising the steps of:

detecting a vibration present at a third position within the electric machine with a third sensor mounted at the third position;

transmitting a signal corresponding to the vibration present at the third position from the third sensor to the controller;

detecting a vibration present at a fourth position within the electric machine with a fourth sensor mounted at the fourth position, wherein the third position and the fourth position are located in a plane orthogonal to the shaft of the electric machine; and

transmitting a signal corresponding to the vibration present at the fourth position from the fourth sensor to the controller, wherein the controller further adjusts operation of the electric machine as a function of the signals corresponding to the vibration detected at the third and fourth positions.