Method of controlling a pump and motor

• US 9,556,874 B2
• Filed: 06/09/2009
• Issued: 01/31/2017
• Est. Priority Date: 06/09/2009
• Status: Active Grant

• Current Assignee: Pentair Flow Technologies LLC (Pentair Plc (Ireland))
• Original Assignee: Danfoss Drives A/S (Danfoss A/S), Pentair Flow Technologies LLC (Pentair Plc (Ireland))
• Inventors: Kidd, Melissa Drechsel, Genaw, William James, Pasche, Micheal Robert, Baase, Gary Thomas II, Berthelsen, Lars Hoffmann, Fink, Rasmus, Holm, Martin Skov
• Primary Examiner(s): Stigell, Theodore
• Assistant Examiner(s): HOFFMANN, JON D
• Application Number:
  US12/481,435
• Publication Number:
  US 20100310382A1
• Time in Patent Office: 2,793 Days
• Field of Search: 417/12, 417/44.1, 417/44.2, 417/44.4, 417/45, 417/53, 417/42, 417/63, 318/723, 318/807
• US Class Current: 1/1
• 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 47/00 Pumps or pumping installations specially adapted for raising fluids from great depths, e.g. well pumps by using positive or negative pressurised fluid medium acting directly on the liquid to be pumped F04F1/00
• CPC Class Codes: F04B 47/06 having motor-pump units situated at great depth
• 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: F04B 49/10 Other safety measures
• CPC Class Codes: F04D 13/08 for submerged use
• CPC Class Codes: F04D 13/10 adapted for use in mining bore holes
• CPC Class Codes: F04D 15/0066 by changing the speed, e.g. of the driving engine
• CPC Class Codes: F04D 15/0077 Safety measures F04D15/02 takes precedence
• CPC Class Codes: F04D 15/0088 Testing machines
• CPC Class Codes: F04D 15/0209 responsive to a condition of the working fluid F04D15/029 takes precedence
• 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
• CPC Class Codes: F04D 15/0254 the condition being speed or load

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 an operating frequency of the motor has reached a steady state operating frequency, the steady state operating frequency determined by a controller;

monitoring a time after the motor has reached the steady state operating frequency;

causing the pump to temporarily boost a pressure in the fluid system to a temporary boost set point once the motor has reached the steady state operating frequency, the temporary boost in pressure caused by increasing the operating frequency of the motor above the steady state operating frequency, and the temporary boost set point being greater than a pressure set point;

restarting monitoring the time after the motor is no longer operating at the steady state operating frequency;

determining whether the temporarily boosted pressure in the fluid system drops below the temporary boost set point after the pump has stopped the temporary boost by reducing the operating frequency of the motor to the steady state operating frequency; and

causing the pump to enter a sleep mode when the temporarily boosted pressure does not drop after the pump has stopped the temporary boost by reducing the operating frequency of the motor to the steady state operating frequency.

2. The method of claim 1 and further comprising causing the pump to continue normal operation when the temporarily boosted pressure does drop after the pump has stopped the temporary boost.

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

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

5. The method of claim 1 wherein determining whether the motor has reached the 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 a well depth.

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

8. The method of claim 7 and further comprising determining whether the temporarily boosted pressure in the fluid system drops to or below the pressure set point.

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

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

11. The method of claim 1 and further comprising determining whether the temporarily boosted pressure in the fluid system drops within 15 seconds after the pump has stopped the temporary boost.

12. The method of claim 1 and further comprising causing the pump to temporarily boost the pressure in the fluid system after monitoring the time and the motor has reached the steady state operating frequency.

13. 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 when a pressure in the fluid system does not drop after being temporarily boosted;

modifying at least one of a plurality of parameters to set a predetermined time period;

determining whether the pump has entered the sleep mode during the predetermined time period, the determining performed by a controller; and

shutting down the pump when the controller determines that the pump has not entered the sleep mode during the predetermined time period.

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

15. The method of claim 13 wherein the predetermined time period is up to fourteen days.

16. The method of claim 13 and further comprising determining whether the motor has reached a steady state operating frequency.

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

18. The method of claim 13 and further comprising indicating on a display that there has been a pipe break fault.

19. The method of claim 13 and further comprising automatically causing a relay output to be energized when there is a pipe break fault.

20. The method of claim 13 and further comprising modifying the predetermined time period.

21. The method of claim 13 and further comprising temporarily shutting down the pump when the controller determines that the pump has not entered the sleep mode during the predetermined time period.

22. 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 first low frequency for a first time period when the pressure in the fluid system is less than a minimum pressure set point in order to fill the fluid system;

operating the motor in the line fill mode at a second low frequency for a second time period when the pressure in the fluid system is less than the minimum pressure set point after the first time period, the second low frequency is a higher frequency than the first low frequency; 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, the normal operating frequency is a higher frequency than the second low frequency.

23. The method of claim 22 and further comprising operating the motor at at least one of the first low frequency and the second low frequency until the pressure reaches a pressure set point of 10 pounds per square inch.

24. The method of claim 22 wherein the first time period and the second time period are five minutes in duration.

25. The method of claim 22 wherein the first low frequency is 45 Hertz.

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

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

28. The method of claim 22 and further comprising automatically operating the motor in the line fill mode unless a manual interrupt feature is enabled.

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

30. The method of claim 22 and further comprising operating the motor in the line fill mode in order to help prevent water hammering.

31. The method of claim 22 and further comprising manually stopping and starting the motor and then operating the motor in the line fill mode after the motor has been manually stopped and then started again.

32. The method of claim 22 and further comprising operating the motor at the normal frequency after the line fill mode and increasing the pressure up to the normal pressure set point of 60 pounds per square inch.

33. 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 is operating below a pre-specified frequency;

determining an actual pressure in the fluid system;

comparing the actual pressure to a preset pressure set point;

resetting a timer when the motor is determined to be operating below the pre-specified frequency and the actual pressure is above the preset pressure set point;

incrementing the timer when the motor is determined to be operating below the pre-specified frequency and the actual pressure is below the preset pressure set point; and

generating a dry run fault when the preset pressure set point cannot be achieved before the timer value exceeds a pre-specified time period, when the motor is operating below the pre-specified frequency and the actual pressure is below the preset pressure set point.

34. The method of claim 33 wherein the pre-specified frequency is 30 Hertz.

35. The method of claim 33 and further comprising comparing the actual pressure to the preset pressure set point of 10 pounds per square inch.

36. The method of claim 33 and further comprising determining the actual pressure adjacent to a pressure tank fluidly coupled to the pump.