Mechanical calibration of turbine over speed trip

Patent metadata

Field	Value
Publication number	US-11098611-B2
Application number	US-201916256667-A
Country	US
Kind code	B2
Filing date	Jan 24, 2019
Priority date	Jan 24, 2019
Publication date	Aug 24, 2021
Grant date	Aug 24, 2021

Abstract

Techniques for mechanical calibration of turbine overspeed trip are described. An electric motor rotates a rotational electric motor shaft coupled to an over speed trip collar of a rotational shaft of an electric machine at multiple rotational speeds. The over speed trip collar is configured to trip in response to the rotational electric motor shaft being rotated at a particular rotational speed. The over speed trip collar triggers an alarm when a rotational speed of the multiple rotational speeds substantially matches the particular rotational speed. The alarm provides a signal in response to triggering the alarm.

First claim

The invention claimed is:

1. A method comprising:
rotationally coupling an over speed trip collar of a rotational shaft of an electric machine to a rotational electric motor shaft, the over speed trip collar configured to trip in response to the rotational shaft of the electric machine being rotated at a particular rotational speed, wherein rotationally coupling the over speed trip collar to the rotational electric motor shaft comprises:
rotationally coupling an end of the rotational electric motor shaft to a first hub assembly;
rotationally coupling the first hub assembly to a second hub assembly; and
rotationally coupling an end of the second hub assembly to the over speed trip collar;

variably rotating the rotational electric motor shaft at a plurality of rotational speeds;
determining that the over speed trip collar trips at a rotational speed of the plurality of rotational speeds; and
determining the rotational speed of the plurality of rotational speeds at which the over speed trip collar trips as the particular rotational speed at which the over speed trip collar is configured to trip when implemented with the rotational shaft of the electric machine.

2. The method of claim 1 , wherein the second hub assembly comprises a rotational shaft of the second hub assembly, wherein rotationally coupling the end of the second hub assembly to the over speed trip collar comprises rotationally coupling an end of the rotational shaft of the second hub assembly to the over speed trip collar.

3. The method of claim 2 , wherein rotationally coupling the end of the rotational shaft of the second hub assembly to the over speed trip collar comprises inserting the end of the rotational shaft of the second hub assembly into the over speed trip collar.

4. The method of claim 1 , the rotational electric motor shaft is variably rotated using a variable frequency drive (VFD) coupled to and configured to operate the rotational electric motor shaft.

5. The method of claim 1 , wherein the over speed trip collar comprises a trigger pin configured to extend radially away from a rotational axis of the rotational electric motor shaft in response to the rotational electric motor shaft rotating at the particular rotational speed, wherein determining the rotational speed of the plurality of rotational speeds at which the over speed trip collar trips comprises:
spatially positioning an alarm relative to the trigger pin, the trigger pin configured to trigger the alarm in response to the trigger pin extending radially away from the rotational axis of the rotational electric motor shaft; and
detecting the alarm being triggered.

6. The method of claim 5 , wherein the trigger pin is configured to contact the alarm in response to extending radially away from the rotational axis of the rotational shaft of the electric machine, wherein detecting the alarm being triggered comprises detecting an audible sound emitted by the alarm in response to being contacted by the trigger pin.

7. The method of claim 1 , further comprising, in response to determining the rotational speed of the plurality of rotational speeds, modifying the particular rotational speed at which the over speed trip collar is configured to trip by modifying one or more structural parameters of the over speed trip collar.

8. The method of claim 1 , wherein the over speed trip collar is detached from the electric machine before rotationally coupling the over speed trip collar of the rotational shaft of the electric machine to the rotational electric motor shaft.

9. The method of claim 1 , wherein the electric machine is a turbine.

10. A method comprising:
rotating, by an electric motor and at a plurality of rotational speeds, a rotational electric motor shaft coupled to an over speed trip collar of a rotational shaft of an electric machine, the over speed trip collar configured to trip in response to the rotational electric motor shaft being rotated at a particular rotational speed;
triggering, by the over speed trip collar, an alarm when a rotational speed of the plurality of rotational speed substantially matches the particular rotational speed; and
providing, by the alarm, a signal in response to triggering the alarm.

11. The method of claim 10 , wherein the alarm is spatially positioned relative to the over speed trip collar to be contacted by a trigger pin of the trip collar in response to the over speed trip collar tripping, wherein triggering, by the over speed trip collar, the alarm comprises contacting, by the trigger pin, a plunger of the alarm.

12. The method of claim 11 , wherein the signal is an audible signal generated in response to the trigger pin contacting the plunger of the alarm.

13. The method of claim 10 , wherein the alarm comprises a displacement sensor configured to sense a distance between the trigger pin and the displacement sensor, wherein the method further comprises determining, by the displacement sensor, that a distance between the trigger pin and the displacement sensor is less than a distance threshold.

14. The method of claim 13 , wherein the signal is an audible signal generated by an audio source connected to the displacement sensor in response to determining that the distance is less than the distance threshold.

15. The method of claim 10 , wherein the over speed trip collar is detached from the electric machine before rotationally coupling the over speed trip collar of the rotational shaft of the electric machine to the rotational electric motor shaft.

16. The method of claim 10 , wherein the electric machine is a turbine.

17. An overtrip calibration system comprising:
an electric motor comprising a rotational electric motor shaft configured to rotationally couple to an over speed trip collar of a rotational shaft of a turbine, the over speed trip collar configured to trip in response to being rotated at or above a particular rotational speed;
a first hub assembly configured to be coupled to the trip collar;
a second hub assembly coupled to the first hub assembly, wherein the second hub assembly is coupled to the rotational electric motor shaft;
a controller coupled to the rotational electric motor shaft, the controller configured to variably rotate the rotational electric motor shaft at a plurality of rotational speeds including at or above the particular rotational speed; and
an alarm spatially arranged relative to the over speed trip collar, the alarm configured to produce a signal in response to the over speed trip collar tripping.

18. The system of claim 17 , wherein the controller comprises a variable frequency drive.

19. The system of claim 17 , wherein the over speed trip collar comprises a trigger pin configured to extend radially away from a rotational axis of the rotational electric motor shaft in response to the over speed trip collar tripping, wherein the signal is an audible signal, wherein the alarm is configured to produce the audible signal in response to the trigger pin extending radially away from the rotational axis of the rotational electric motor shaft and contacting the alarm,
wherein the system further comprises an adjusting nut formed in a circumferential surface of the trip collar, wherein the trigger pin is positioned diametrically opposite to the adjusting nut, wherein the adjusting nut is configured to be adjusted to modify a centrifugal force at which the trigger pin extends radially away from the rotational axis of the rotational electric motor shaft.

20. The system of claim 17 , further comprising a safety guar

Assignees

• Saudi Arabian Oil Co

Inventors

• Rasheed Hussain H
• Alturki Abdulkareem A

Classifications

• G01H1/08

  Amplitude · CPC title

• H01H35/10 Primary

  Centrifugal switches (level of mercury displaced by centrifugal action H01H29/26) · CPC title

• F01D21/003

  Arrangements for testing or measuring (for measuring vibrations G01H) · CPC title

• G01R31/343

  in operation · CPC title

• F05D2270/021

  to prevent overspeed · CPC title