Controller for a motor and a method of controlling the motor

• US 20050226731A1
• Filed: 04/08/2005
• Published: 10/13/2005
• Est. Priority Date: 04/09/2004
• Status: Active Grant

• Current Assignee: Regal Beloit America, Inc. (Regal Rexnord Corp.)
• Original Assignee: A. O. Smith Corporation
• Inventors: Phillips, Andrew Williams, Mehlhorn, William Louis
• Granted Patent: US 8,177,520 B2
• Time in Patent Office: Days
• US Class Current: 417/44.110
• CPC Class Codes: F04D 15/0066 by changing the speed, e.g. of the driving engine
• CPC Class Codes: F04D 15/0236 Lack of liquid level being detected by analysing the parameters of the electric drive, e.g. current or power consumption

Abstract

A method of controlling a motor operating a pumping apparatus of a fluid-pumping application. The pumping apparatus includes a pump having an inlet to receive a fluid and an outlet to exhaust the fluid, and the motor coupled to the pump to operate the pump. The method includes the acts of controlling the motor to operate the pump and monitoring the operation of the pump. The monitoring act includes monitoring a power of the motor, and determining whether the monitored power indicates an undesired flow of fluid through the pump. The method further includes the act of controlling the motor to cease operation of the pump when the determination indicates an undesired flow of fluid through the pump and zero or more other conditions exist.

Claims

1. A pumping apparatus for a jetted-fluid system comprising a vessel for holding a fluid, a drain, and a return, the pumping apparatus being connectable to a power source and comprising:

a pump comprising an inlet connectable to the drain, and an outlet connectable to the return, the pump adapted to receive the fluid from the drain and jet fluid through the return;

a motor coupled to the pump to operate the pump;

a voltage sensor coupled to the motor and configured to generate a first signal having a relation to a voltage applied to the pump motor;

a current sensor coupled to the motor and configured to generate a second signal having a relation to a current applied to the pump motor;

a switch connectable to the power source and coupled to the motor, and the switch configured to control the current through the motor; and

a controller coupled to the voltage sensor, the current sensor, and the switch, the controller configured to generate a value based on the first and second signals, the value having a relation to the motor input power, and to control the motor based on the value.

2. A pumping apparatus as set forth in claim 1 wherein the pumping apparatus further comprises a first zero crossing detector coupled to the motor and configured to generate a third signal having a relation to the zero crossings of the voltage applied to the pump motor, and a second zero crossing detector coupled to the motor and configured to generate a fourth signal having a relation to the zero crossings of the current through the motor, and wherein the value is further based on the third and fourth signals.

3. A pumping apparatus as set forth in claim 2 wherein the first zero crossing detector is coupled to the voltage sensor, receives the first signal, and generates the third signal based on the first signal, and wherein the second zero crossing detector is coupled to the current sensor, receives the second signal, and generates the fourth signal based on the second signal.

4. A pumping apparatus as set forth in claim 3 wherein the controller is configured to determine a motor power factor based on the third and fourth signals.

5. A pumping apparatus as set forth in claim 1 wherein the pumping apparatus further comprises a first circuitry coupled to the voltage sensor and to the controller, the first circuitry configured to receive the first signal and produce a third signal representing an averaged value for the first signal, and a second circuitry coupled to the voltage sensor and to the controller, the second circuitry configured to receive the second signal and produce a fourth signal representing an averaged value for the second signal, and wherein the controller generates the value based on the third and fourth signals.

6. A pumping apparatus as set forth in claim 5 wherein the control of the motor based on the value representing the motor input power comprises the controller being further configured to

monitor the motor input power,

determine whether the monitored power indicates an undesired flow of fluid through the pump, and

control the motor to cease operation of the pump when the determination indicates an undesired flow of fluid through the pump and zero or more other conditions exist.

7. A pumping apparatus as set forth in claim 6 wherein the determination whether the monitored power indicates an undesired flow of fluid comprises the controller being further configured to determine whether the monitored power indicates an undesired low fluid inlet flow, and wherein the control of the motor to cease operation of the pump when the determination indicates an undesired flow of fluid comprises the controller being further configured to control the motor to cease operation of the pump when the determination indicates an undesired low fluid inlet flow and zero or more other conditions exist.

8. A pumping apparatus as set forth in claim 6 wherein the determination whether the monitored power indicates an undesired flow of fluid comprises the controller being further configured to determine whether the monitored power indicates an undesired high fluid outlet flow, and wherein the control of the motor to cease operation of the pump when the determination indicates an undesired flow of fluid comprises the controller being further configured to control the motor to cease operation of the pump when the determination indicates an undesired high fluid outlet flow and zero or more other conditions exist.

9. A pumping apparatus as set forth in claim 6 wherein the controller comprises a memory configurable to store a power calibration value, and wherein the determination whether the monitored power indicates an undesired flow of fluid comprises the controller being further configured to determine whether the monitored power is not within a window of the power calibration value, the window indicative of a desired flow of fluid through the pump.

10. A pumping apparatus as set forth in claim 6 wherein the controller comprises a memory configurable to store a threshold indicative of an undesired low fluid inlet flow, and wherein the determination whether the monitored power indicates an undesired flow of fluid comprises the controller being further configured to determine whether the monitored power is less than the threshold.

11. A pumping apparatus as set forth in claim 6 wherein the controller comprises a memory configurable to store a threshold indicative of an undesired high fluid outlet flow, and wherein the determination whether the monitored power indicates an undesired flow of fluid comprises the controller being further configured to determine whether the monitored power is greater than the threshold.

12. A pumping apparatus as set forth in claim 1 wherein the pumping apparatus further comprises a pressure sensor coupled to the pump inlet and configured to generate a third signal having a relation to the pump inlet side pressure, wherein the controller is coupled to the pressure sensor, and wherein the controller is further configured to control the motor based on the third signal.

13. A method of controlling a motor operating a pumping apparatus of a fluid-pumping application, the pumping apparatus comprising

a pump having an inlet to receive a fluid and an outlet to exhaust the fluid, and

the motor coupled to the pump to operate the pump, the method comprising:

controlling the motor to operate the pump;

monitoring the operation of the pump, the monitoring act comprising

monitoring a power of the motor, and

determining whether the monitored power indicates a condition of the pump; and

controlling the motor to operate the pump based on the condition of the pump and zero or more other conditions.

14. A method as set forth in claim 13 wherein the condition of the pump is an undesired flow of fluid through the pump.

15. A method as set forth in claim 13 wherein the condition of the pump is a desired flow of fluid through the pump.

16. A method as set forth in claim 13 wherein the act of monitoring a power comprises sensing a motor voltage, sensing a motor current, and determining a power of the motor based on the sensed motor voltage and the sensed motor current.

17. A method as set forth in claim 16 wherein the pumping apparatus further comprises a voltage sensor and a current sensor coupled to the motor, wherein sensing a motor voltage comprises sensing a voltage applied to the motor with the voltage sensor, and wherein sensing a motor current comprises sensing a current through the motor with the current sensor.

18. A method as set forth in claim 13 wherein the act of monitoring a power comprises sensing a voltage applied to the motor, determining an averaged motor voltage based on the sensed voltage, sensing a current through the motor, determining an averaged motor current based on the sensed current, determining a power factor for the motor based on the sensed voltage and the sensed current, and determining the motor power with the averaged motor voltage, the averaged motor current, and the motor power factor.

19. A method as set forth in claim 18 wherein the act of determining a power factor for the motor comprises sensing a first zero-crossing of the sensed voltage, sensing a second zero-crossing of the sensed current, and determining the power factor for the motor based on the sensed zero-crossings.

20. A method as set forth in claim 13 wherein the determining act comprises determining whether the monitored power indicates a low fluid inlet flow, and wherein the act of controlling the motor to operate the pump comprises controlling the motor to cease operation of the pump when the determination indicates a low fluid inlet flow and zero or more other conditions exist.

21. A method as set forth in claim 13 wherein the determining act comprises determining whether the monitored power indicates a high fluid outlet flow, and wherein the act of controlling the motor to operate the pump comprises controlling the motor to cease operation of the pump when the determination indicates a high fluid outlet flow and zero or more other conditions exist.

22. A method as set forth in claim 13 wherein the method further comprises calibrating the motor to obtain a power calibration value, and wherein the determining act comprises determining whether the monitored power is within a window of the power calibration value, the window indicative of a desired flow of fluid through the pump.

23. A method as set forth in claim 13 wherein the method further comprises calibrating the motor to obtain a power calibration value, and wherein the determining act comprises determining whether the monitored power is not within a window of the power calibration value, the window indicative of a desired flow of fluid through the pump.

24. A method as set forth in claim 23 wherein the act of calibrating the motor comprises initiating a calibration event, determining a power of the motor in response to initiating the calibration event, and setting the power calibration value to the determined power.

25. A method as set forth in claim 13 wherein the determining act comprises determining whether the monitored power is less than a threshold indicative of a low fluid inlet flow.

26. A method as set forth in claim 13 wherein the determining act comprises determining whether the monitored power is greater than a threshold indicative of a high fluid outlet flow.

27. A method as set forth in claim 13 wherein the method further comprises monitoring a pump inlet side pressure, determining whether the monitored pressure indicates a low fluid inlet flow, and controlling the motor to cease operation of the pump when the determination indicates a low fluid inlet flow and zero or more other conditions exist.

28. A method as set forth in claim 13 wherein the zero or more other conditions consists of zero conditions.

29. A method as set forth in claim 13 wherein the method further comprises indicating a normal operation state for the pumping apparatus, and wherein the act of controlling the motor to operate the pump comprises controlling the motor to cease operation of the pump when the determination indicates an undesired flow, the pumping apparatus is in a normal operation state, and zero or more other conditions exist.

30. A method as set forth in claim 13 wherein the act of controlling the motor to operate the pump comprises initiating operation of the motor to prime the pump, wherein the method further comprises indicating a lockout state when initiating operation of the motor to prime the pump, and ceasing the lockout state, and wherein the act of controlling the motor to operate the pump comprises controlling the motor to cease operation of the pump when the determination indicates an undesired flow, the pumping apparatus is in a normal operation state, and zero or more other conditions exist.

31. A method as set forth in claim 30 wherein the lockout state lasts a time period.

32. A method as set forth in claim 30 wherein the method comprises calibrating the motor to obtain a power calibration value, wherein ceasing the lockout state comprises monitoring a power of the motor and determining whether the monitored power is within a window of the power calibration value for a time period, the window indicative of a desired flow of fluid through the pump.

33. A method as set forth in claim 30 wherein ceasing the lockout state comprises monitoring a power of the motor pump and determining whether the monitored power is greater than a threshold for a time period.

34. A method as set forth in claim 33 wherein the time period is an instantaneous time period.

35. A method of detecting an entrapment event in a jetted-fluid system comprising a vessel for holding a fluid, a drain, a return, and a pumping apparatus coupled to the drain and the return, the pumping apparatus comprising

a pump comprising an inlet coupled to the drain and an outlet coupled to the return, and

a motor coupled to the pump to operate the pump, the method comprising:

during a normal operation state,

powering the motor;

pumping the fluid with the pumping apparatus while powering the motor, the pumping act comprising suctioning the fluid from the vessel through the drain and jetting the pumped fluid into the vessel through return;

monitoring the drain for an entrapment event, the monitoring act comprising

monitoring an input power of the motor, and

determining whether the monitored power indicates a possible entrapment event, and

initiating a fault state when the determination indicates an entrapment event and zero or more other conditions exist;

during the fault state,

powering down the motor; and

ceasing the pumping of the fluid after powering down the motor.

36. A method as set forth in claim 35 wherein the act of monitoring an input power comprises sensing a voltage applied to the motor, determining an averaged motor voltage based on the sensed voltage, sensing a current through the motor, determining an averaged motor current based on the sensed current, determining a power factor for the motor based on the sensed voltage and the sensed current, and determining the input power with the averaged motor voltage, the averaged motor current, and the motor power factor.

37. A method as set forth in claim 36 wherein the act of determining a power factor for the motor comprises sensing a first zero-crossing of the sensed voltage, sensing a second zero-crossing of the sensed current, and determining the power factor for the motor based on the sensed zero-crossings.

38. A method as set forth in claim 35 wherein the method further comprises calibrating the motor to obtain a power calibration value, and wherein the determining act comprises determining whether the monitored power is not within a window of the power calibration value, the window indicative of the pump operating normally.

39. A method as set forth in claim 35 wherein the determining act comprises determining whether the monitored power is less than a threshold indicative of a possible entrapment event.

40. A method as set forth in claim 35 wherein the method further comprises monitoring a pump inlet side pressure, determining whether the monitored pressure indicates a possible entrapment event.

41. A method as set forth in claim 35 and further comprising:

during a first state,

initiating operation of the motor;

priming the pump after the initiating act;

monitoring the operation of the pump, the monitoring act comprising

monitoring a power of the motor, and

determining whether the monitored power indicates the pump can be monitored for entrapment;

ceasing the first state and entering the normal operation state when the monitored power indicates the pump can be monitored for entrapment and zero or more other conditions exist.

42. A method of detecting an entrapment event in a jetted-fluid system comprising a vessel for holding a fluid, a drain, a return, and a pumping apparatus coupled to the drain and the return, the pumping apparatus comprising

a pump comprising an inlet coupled to the drain and an outlet coupled to the return,

a motor coupled to the pump to operate the pump, the method comprising:

during a first state,

initiating operation of the motor;

priming the pump after the initiating act;

monitoring the operation of the pump, the monitoring act comprising

monitoring an input power of the motor, and

determining whether the monitored power indicates the pump can be monitored for entrapment;

ceasing the first state and entering a normal operation state when the monitored power indicates the pump can be monitored for entrapment and zero or more other conditions exist;

during the normal operation state;

pumping the fluid with the pumping apparatus while powering the motor, the pumping act comprising suctioning the fluid from the vessel through the drain and jetting the pumped fluid through return; and

monitoring the drain for an entrapment event, the monitoring act comprising monitoring an input power of the motor.

43. A method as set forth in claim 42 wherein the act of monitoring an input power comprises sensing a voltage applied to the motor, determining an averaged motor voltage based on the sensed voltage, sensing a current through the motor, determining an averaged motor current based on the sensed current, determining a power factor for the motor based on the sensed voltage and the sensed current, and determining the input power with the averaged motor voltage, the averaged motor current, and the motor power factor.

44. A method as set forth in claim 43 wherein the act of determining a power factor for the motor comprises sensing a first zero-crossing of the sensed voltage, sensing a second zero-crossing of the sensed current, and determining the power factor for the motor based on the sensed zero-crossings.

45. A method as set forth in claim 42 wherein the method comprises calibrating the motor to obtain a power calibration value, wherein the determining act comprises determining whether the monitored power is within a window of the power calibration value, and wherein the ceasing act comprises ceasing the first state and entering a normal operation state when the monitored power is within a window of the power calibration value for a time period and zero or more other conditions exist.

46. A method as set forth in claim 42 wherein the determining act comprises determining whether the monitored power is greater than a threshold value, and wherein the ceasing act comprises ceasing the first state and entering a normal operation state when the monitored power is greater than a threshold value for a time period and zero or more other conditions exist.

47. A method as set forth in claim 46 wherein the time period is an instantaneous time period.