Method of Controlling a Pump and Motor

• US 20100310382A1
• Filed: 06/09/2009
• Published: 12/09/2010
• Est. Priority Date: 06/09/2009
• Status: Active Grant

• Current Assignee: Pentair Flow Technologies LLC (Pentair Plc (Ireland))
• Original Assignee: Pentair Flow Technologies LLC (Pentair Plc (Ireland))
• Inventors: Holm, Martin Skov, Kidd, Melissa Drechsel, Pasche, Micheal Robert, Fink, Rasmus, Genaw, William James, Baase II, Gary Thomas, Berthelsen, Lars Hoffmann
• Granted Patent: US 9,556,874 B2
• Time in Patent Office: Days
• US Class Current: 417/12
• CPC Class Codes: F04B 17/03 driven by electric motors
• CPC Class Codes: F04B 2203/0204 Frequency of the electric current
• CPC Class Codes: F04B 2205/04 Pressure in the outlet chamber
• CPC Class Codes: F04B 2205/05 Pressure after the pump outlet
• CPC Class Codes: F04B 49/06 Control using electricity regulating by means of floats actuating electric switches F04B49/04
• CPC Class Codes: F04B 49/065 and making use of computers
• CPC Class Codes: F04B 49/08 Regulating by delivery pressure
• CPC Class Codes: F04D 13/08 for submerged use
• CPC Class Codes: F04D 15/0066 by changing the speed, e.g. of the driving engine
• CPC Class Codes: F04D 15/0209 responsive to a condition of the working fluid F04D15/029 takes precedence

Abstract

Embodiments of the invention provide a variable frequency drive system and a method of controlling a pump driven by a motor with the pump in fluid communication with a fluid system. The drive system and method can provide one or more of the following: a sleep mode, pipe break detection, a line fill mode, an automatic start mode, dry run protection, an electromagnetic interference filter compatible with a ground fault circuit interrupter, two-wire and three-wire and three-phase motor compatibility, a simple start-up process, automatic password protection, a pump out mode, digital input/output terminals, and removable input and output power terminal blocks.

Claims

1. A method of controlling a pump driven by a motor, the pump in fluid communication with a fluid system, the method comprising:

determining whether the motor has reached a steady state operating frequency;

causing the pump to temporarily boost a pressure in the fluid system once the motor has reached a steady state operating frequency;

determining whether the pressure in the fluid system drops after being temporarily boosted; and

causing the pump to enter a sleep mode if the pressure does not drop after being temporarily boosted.

2. The method of claim 1 and further comprising causing the pump to continue normal operation if the pressure does drop after being temporarily boosted.

3. The method of claim 2 and further comprising periodically determining whether the motor has reached a steady state operating frequency again.

4. The method of claim 3 and further comprising determining whether the motor has reached a steady state operating frequency about every two minutes.

5. The method of claim 1 wherein determining whether the motor has reached a steady state operating frequency includes determining whether the speed of the motor is steady.

6. The method of claim 1 wherein entering the sleep mode is independent of well depth.

7. The method of claim 1 and further comprising boosting the pressure by about three pounds per square inch.

8. The method of claim 7 and further comprising determining whether the pressure drops below a pressure set point.

9. The method of claim 1 and further comprising disabling the sleep mode when the pressure drops to below a pressure set point minus about five pounds per square inch.

10. The method of claim 1 and further comprising determining whether the motor has reached a steady state operating frequency by determining whether a frequency of the motor has stayed constant for at least about one minute.

11. The method of claim 1 and further comprising determining whether the pressure in the fluid system drops within about 15 seconds after being temporarily boosted.

12. A method of controlling a pump driven by a motor, the pump in fluid communication with a fluid system, the method comprising:

causing the pump to enter a sleep mode if a pressure in the fluid system does not drop after being temporarily boosted;

determining whether the pump has entered the sleep mode during a predetermined time period; and

shutting down the pump due to a pipe break fault if the pump has not entered the sleep mode during the predetermined time period.

13. The method of claim 12 wherein the predetermined time period is at least about four hours.

14. The method of claim 12 wherein the predetermined time period is up to about fourteen days.

15. The method of claim 12 and further comprising determining whether the motor has reached a steady state operating frequency.

16. The method of claim 15 and further comprising causing the pump to temporarily boost the pressure in the fluid system once the motor has reached a steady state operating frequency.

17. The method of claim 12 and further comprising indicating on a display that there has been a pipe break fault.

18. The method of claim 12 and further comprising automatically causing a relay output to be energized when there is a pipe break fault.

19. The method of claim 12 and further comprising modifying the predetermined time period.

20. The method of claim 12 and further comprising temporarily disabling the pipe break fault.

21. A method of controlling a pump driven by a motor, the pump in fluid communication with a fluid system, the method comprising:

determining a pressure in the fluid system when the pump starts;

operating the motor in a line fill mode at a low frequency for a time period if the pressure in the fluid system is less than a minimum pressure set point in order to fill the fluid system; and

operating the motor at a normal frequency after the minimum pressure set point is reached in order to increase the pressure to a normal pressure set point.

22. The method of claim 21 and further comprising operating the motor at a low frequency until the pressure reaches a pressure set point of about 10 pounds per square inch.

23. The method of claim 21 and further comprising operating the motor at a low frequency for a time period of about five minutes.

24. The method of claim 21 and further comprising operating the motor at a low frequency of about 45 Hertz.

25. The method of claim 24 and further comprising operating the motor at about 45 Hertz for about one minute to about five minutes, then operating the motor at about 45 Hertz to about 50 Hertz for about three minutes to about five minutes, and then operating the motor at about 55 Hertz for about one minute, if the pressure has not reached the minimum pressure set point.

26. The method of claim 25 and further comprising operating the motor at about 55 Hertz for about five minutes if the pressure has not reached the minimum pressure set point.

27. The method of claim 21 and further comprising automatically operating the motor in the line fill mode unless a manual interrupt feature is enabled.

28. The method of claim 27 and further comprising enabling the manual interrupt feature by manually changing a speed of the motor.

29. The method of claim 21 and further comprising operating the motor in the line fill mode in order to help prevent water hammering.

30. The method of claim 21 and further comprising operating the motor in the line fill mode after the motor has been manually stopped and then started again.

31. The method of claim 21 and further comprising operating the motor at the normal frequency after the line fill mode and increasing the pressure up to a normal pressure set point of about 60 pounds per square inch.

32. A controller for a pump driven by a motor, the pump in fluid communication with a fluid system, the controller comprising:

a variable frequency drive circuit that controls operation of the pump; and

a control panel connected to the variable frequency drive circuit,

the control panel including an automatic start button and a stop button,

the variable frequency drive circuit automatically operating in a line fill mode when the pump starts when the automatic start button is engaged,

the variable frequency drive circuit disabling the pump when the stop button is engaged.

33. The controller of claim 32 wherein the variable frequency drive circuit operates in the line fill mode by determining a pressure in the fluid system when the pump starts.

34. The controller of claim 33 wherein the variable frequency drive circuit operates the motor at a low frequency for a time period if the pressure in the fluid system is less than a minimum pressure set point in order to fill the fluid system.

35. The controller of claim 34 wherein the variable frequency drive circuit operates the motor at a normal frequency after the timer period has expired in order to maintain a normal pressure set point.

36. The controller of claim 32 wherein the variable frequency drive circuit automatically starts and operates in the line fill mode after a power interruption if the automatic start button is engaged.

37. A method of controlling a pump driven by a motor, the pump in fluid communication with a fluid system, the method comprising:

operating the motor at a normal operating frequency;

determining an actual pressure in the fluid system;

comparing the actual pressure to a pressure set point; and

generating a dry run fault if the pressure set point cannot be achieved by operating the motor at the normal operating frequency.

38. The method of claim 37 and further comprising operating the motor at a normal operating frequency above about 30 Hertz.

39. The method of claim 37 and further comprising comparing the actual pressure to a pressure set point of about 10 pounds per square inch.

40. The method of claim 37 and further comprising determining an actual pressure adjacent to a pressure tank fluidly coupled to the pump.