Motor control center units including auxiliary power interlock circuits and methods of operating same

Patent metadata

Field	Value
Publication number	US-9338904-B2
Application number	US-201414251138-A
Country	US
Kind code	B2
Filing date	Apr 11, 2014
Priority date	Apr 11, 2014
Publication date	May 10, 2016
Grant date	May 10, 2016

Abstract

A motor control center (MCC) unit for installation in a compartment of an MCC includes a frame, a bus contact assembly supported by the frame and comprising at least one moveable bus contact configured to releasably engage at least one power bus of the MCC, an auxiliary power input supported by the frame and configured to be connected to an external power source, and a control circuit supported by the frame. The MCC unit further includes an interlock circuit configured to selectively couple the control circuit to the at least one bus contact and the auxiliary power input responsive to positioning of the at least one bus contact. The interlock circuit may be configured to prevent power flow between the control circuit and the auxiliary power input when the at least one bus contact is engaged with the power bus.

First claim

That which is claimed is:

1. A motor control center (MCC) unit for installation in a compartment of an MCC, the MCC unit comprising:
a frame;
a bus contact assembly supported by the frame and comprising at least one moveable bus contact configured to releasably engage at least one power bus of the MCC;
an auxiliary power input supported by the frame and configured to be connected to an external power source;
a control circuit supported by the frame; and
an interlock circuit configured to selectively couple:
when the at least one bus contact is in a first position, the control circuit is coupled to the at least one bus contact and the control circuit is decoupled from the auxiliary power input; and
when the at least one bus contact is in a second position, the control circuit is coupled to the auxiliary power input and the control circuit is decoupled from the at least one bus contact, the first position being different than the second position.

2. The MCC unit of claim 1 , wherein the interlock circuit is configure to prevent power flow between the control circuit and the auxiliary power input when the at least one bus contact is in a first position and engaged with the at least one power bus.

3. The MCC unit of claim 1 , wherein the interlock circuit comprises at least one switch configured to couple and decouple the control circuit and the at least one bus contact responsive to positioning of the at least one bus contact.

4. The MCC unit of claim 1 , wherein the interlock circuit comprises at least one switch configured to couple and decouple the control circuit and the auxiliary power input responsive to positioning of the at least one bus contact.

5. The MCC unit of claim 1 , further comprising a circuit interruption device supported by the frame and configured to couple and decouple a load and the at least one bus contact, wherein the interlock circuit is configured to selectively couple only one of the at least one bus contact to the control circuit or the auxiliary power input to the control circuit responsive to a state of the circuit interruption device.

6. The MCC unit of claim 5 , wherein the interlock circuit comprises at least one auxiliary contact set of the circuit interruption device.

7. The MCC unit of claim 6 , wherein the at least one auxiliary contact set comprises a first auxiliary contact set of the circuit interruption device configured to couple and decouple the control circuit and the at least one bus contact, and a second auxiliary contact set of the circuit interruption device configured to couple and decouple the control circuit and the auxiliary power input.

8. The MCC unit of claim 1 , wherein the interlock circuit comprises a first relay contact set configured to couple and decouple the control circuit and the auxiliary power input, and a second relay contact set configured to couple and decouple the control circuit and the at least one bus contact.

9. The MCC unit of claim 8 , wherein the interlock circuit further comprises at least one switch configured to operate the first and second relay contact sets responsive to a positioning of the at least one bus contact.

10. The MCC unit of claim 1 , wherein the auxiliary power input comprises a power connector supported by the frame and configured to mate with a matching connector of a power cord.

11. The MCC unit of claim 10 , wherein the power connector is accessible via an opening in a door of the MCC compartment.

12. The MCC unit of claim 10 , wherein the power connector is accessible without opening the door of the MCC compartment.

13. The MCC unit of claim 10 , further comprising a device panel supported by the frame and having a plurality of user interface devices mounted thereon, wherein the power connector is mounted on the device panel.

14. The MCC unit of claim 1 , the interlock circuit comprises a key switch configured to couple and decouple the auxiliary power input and the control circuit in combination with positioning of the at least one bus contact.

15. An MCC unit for installation in a compartment of an MCC, the MCC unit comprising:
a frame;
a bus contact assembly supported by the frame and comprising at least one moveable bus contact configured to selectively engage at least one power bus of the MCC;
an auxiliary power input supported by the frame and configured to be connected to an external power source;
a control circuit supported by the frame; and
an interlock circuit comprising at least one switch configured to decouple the control circuit from the auxiliary power input when the at least one bus contact is engaged with the at least one power bus.

16. The MCC unit of claim 15 , wherein the at least one switch is mechanically actuated by a positioning of the at least one bus contact.

17. The MCC unit of claim 15 , wherein the at least one switch comprises at least one set of relay contacts, and wherein the interlock circuit further comprises a mechanical switch configured to operate the at least one set of relay contacts responsive to positioning of the at least one bus contact.

18. The MCC unit of claim 15 , wherein the at least one switch comprises a first switch configured to decouple the control circuit from the at least one bus contact when the at least one bus contact is disengaged from the at least one power bus, and a second switch configured to couple the control circuit to the auxiliary power input after the control circuit is decoupled from the at least one bus contact.

19. The MCC unit of claim 18 , wherein the second switch is mechanically actuated by a positioning of the at least one bus contact.

20. The MCC unit of claim 18 , wherein the second switch comprises at least one set of relay contacts and wherein the interlock circuit comprises at least one mechanical switch configured to operate the at least one set of relay contacts responsive to positioning of the at least one bus contact.

21. The MCC unit of claim 20 , wherein the at least one set of relay contacts further operates responsive to presence or absence of power at the auxiliary power input.

22. A method comprising: installing a MCC unit in a compartment of an MCC; and
responsive to positioning of at least one moveable bus contact of the MCC unit, selectively coupling:
when the at least one bus contact is in a first position, a control circuit of the MCC unit is coupled to the at least one bus contact and the control circuit is decoupled from an auxiliary power input of the MCC unit; and
when the at least one bus contact is in a second position, the control circuit is coupled to the auxiliary power input and the control circuit is decoupled from the at least one bus contact, the first position being different than the second position.

23. The method of claim 22 , wherein the decoupling the control circuit from the auxiliary power input is responsive to an engagement of the at least one bus contact with at least one power bus of the MCC in the first position.

24. The method of claim 23 , further comprising detecting the engagement of the at least one bus contact with the at least one power bus in the first position using at least one mechanically actuated switch.

Assignees

• Eaton Corp

Inventors

• Stoner James Allen
• Yerse Mark Francis
• Morris Robert Allan

Classifications

• H02B11/133

  with interlock · CPC title

• H05K5/0208 Primary

  Interlock mechanisms; Means for avoiding unauthorised use or function, e.g. tamperproof · CPC title

• H02B1/36 Primary

  with withdrawable units · CPC title

• H05K7/14

  Mounting supporting structure in casing or on frame or rack · CPC title