Methods for correcting slow roll

• US 20060108349A1
• Filed: 09/27/2005
• Published: 05/25/2006
• Est. Priority Date: 09/30/2004
• Status: Active Grant

• Current Assignee: Siemens Large Drives LLC
• Original Assignee: Siemens Industry Incorporated (Siemens AG)
• Inventors: Hodowanec, Mark, Finley, William
• Granted Patent: US 7,635,828 B2
• Time in Patent Office: Days
• US Class Current: 219/469
• CPC Class Codes: H02K 15/165 Balancing the rotor

Abstract

Certain exemplary embodiments comprise a method comprising a plurality of activities comprising, for a shaft of an electric motor, the shaft comprising a runout sensing area: determining an electrical runout value for the runout sensing area; rotating the shaft; and/or heating the runout sensing area of the shaft sufficient to reduce the electrical runout value.

Claims

1. A method comprising a plurality of activities comprising:

for a shaft of an electric motor, the shaft comprising a slow roll sensing area, responsive to a first determined slow roll value, measured at the slow roll sensing area, exceeding a predetermined threshold;

determining a first electrical runout value for the slow roll sensing area from the first determined slow roll value;

rotating the shaft at a speed of less than 25 revolutions per minute;

heating the slow roll sensing area of the shaft to a temperature approximately within a predetermined temperature range for approximately a predetermined time interval, said heating sufficient to reduce the electrical runout value; and

applying a liquid coolant to a non-sensing area of the shaft to resist a thermal distortion of the non-sensing area.

2. The method of claim 1, further comprising:

determining the slow roll sensing area of the shaft.

3. The method of claim 1, further comprising:

measuring a second determined slow roll value after said heating activity.

4. The method of claim 1, further comprising:

measuring a second determined slow roll value after said heating activity; and

determining a second electrical runout value for the slow roll sensing area from the second determined slow roll value.

5. The method of claim 1, further comprising:

measuring the first determined slow roll value at the slow roll sensing area of the shaft.

6. The method of claim 1, further comprising:

reducing the electrical runout value in the slow roll sensing area.

7. The method of claim 1, further comprising:

heating the slow roll sensing area utilizing electric heat.

8. The method of claim 1, further comprising:

heating the slow roll sensing area utilizing a carbonizing flame.

9. The method of claim 1, further comprising:

heating the slow roll sensing area utilizing a carbonizing flame placed between approximately one inch and approximately two inches away from the slow roll sensing area of the shaft.

10. The method of claim 1, further comprising:

grinding the shaft subsequent to said heating activity.

11. The method of claim 1, further comprising:

machining the shaft subsequent to said heating activity.

12. The method of claim 1, further comprising:

monitoring a temperature of the slow roll sensing area via an infrared temperature scanner.

13. The method of claim 1, wherein the predetermined temperature range is between approximately 600 deg. F. and approximately 800 deg. F.

14. The method of claim 1, wherein the predetermined time interval is between approximately six minutes and approximately eight minutes.

15. The method of claim 1, further comprising:

subsequently determining that a second slow roll value at the slow roll sensing area of the shaft is below the predetermined threshold.

16. The method of claim 1, further comprising:

flooding a bearing journal area of the shaft with a liquid coolant during said heating activity.

17. The method of claim 1, further comprising:

cooling the shaft in air.

18. The method of claim 1, further comprising:

cooling the shaft to a temperature below approximately 100 deg. F.

19. A method comprising:

for a shaft comprising a runout sensing area;

determining an electrical runout value for the runout sensing area;

rotating the shaft; and

heating the runout sensing area of the shaft to a temperature approximately within a predetermined temperature range for approximately a predetermined time interval, said heating sufficient to reduce the electrical runout value; and

applying a liquid coolant to a non-sensing area of the shaft.

20. A method comprising:

receiving information indicative of a first electrical runout value of a sensing area of a shaft of an electric motor;

automatically determining a temperature range for heating the sensing area of the shaft to reduce the first electrical runout value;

automatically determining a time interval for heating the sensing area of the shaft to reduce the first electrical runout value; and

automatically heating the sensing area of the shaft sufficient to reduce the first electrical runout value.

21. The method of claim 20, further comprising:

receiving information indicative of a diameter of the shaft.

22. The method of claim 20, further comprising:

receiving information indicative of a length of the shaft.

23. The method of claim 20, further comprising:

receiving information indicative of a profile of the shaft.

24. The method of claim 20, further comprising:

determining a size of a slow roll sensing area of the sensing area of the shaft.

25. The method of claim 20, further comprising:

determining a targeted threshold for reducing the first electrical runout value of the slow roll sensing area of the shaft.

26. The method of claim 20, further comprising:

receiving a temperature of the slow roll sensing area of the shaft.

27. The method of claim 20, further comprising:

automatically controlling the temperature of the slow roll sensing area of the shaft within the temperature range.

28. The method of claim 20, further comprising:

automatically controlling the temperature of the slow roll sensing area of the shaft within the temperature range for a period of time within the time interval.

29. The method of claim 20, further comprising:

automatically cooling a non-sensing area of the shaft.

30. The method of claim 20, further comprising:

determining a targeted rotational speed for the electric motor shaft for heating the shaft to reduce electrical runout.

31. The method of claim 20, further comprising:

determining a targeted rotational speed for the electric motor shaft for heating the shaft to reduce electrical runout; and

automatically controlling rotation of the shaft at approximately the targeted rotational speed.

32. The method of claim 20, further comprising:

determining a cooling rate for the slow roll sensing area of the shaft.

33. The method of claim 20, further comprising:

automatically controlling a cooling rate of the slow roll sensing area of the shaft.

34. The method of claim 20, further comprising:

automatically monitoring the temperature of the shaft during cooling.

35. The method of claim 20, further comprising:

receiving information indicative of a second electrical runout of the slow roll sensing area of the shaft.

36. The method of claim 20, further comprising:

determining that the first electrical runout value exceeds a predetermined threshold.

37. The method of claim 20, further comprising:

determining that a second electrical runout is below a predetermined threshold.

38. A machine-readable medium having stored thereon a plurality of executable instructions, the plurality of instructions comprising instructions to:

receive information indicative of a first electrical runout value of a sensing area of a shaft of an electric motor;

automatically determine a temperature range for heating the sensing area of the shaft to reduce the first electrical runout value;

automatically determine a time interval for heating the sensing area of the shaft to reduce the first electrical runout value; and

automatically heat the sensing area of the shaft sufficient to reduce the first electrical runout value.