Hybrid high voltage DC contactor with arc energy diversion

• US 7,817,382 B2
• Filed: 01/02/2008
• Issued: 10/19/2010
• Est. Priority Date: 01/02/2008
• Status: Active Grant

• Current Assignee: Honeywell International Inc.
• Original Assignee: Honeywell International Inc.
• Inventors: Cheng, Shaobin, Yu, Wenjiang, Liu, Zhenning
• Primary Examiner(s): Jackson; Stephen W
• Assistant Examiner(s): KITOV, ZEEV V
• Application Number:
  US11/968,314
• Publication Number:
  US 20090168273A1
• Time in Patent Office: 1,021 Days
• Field of Search: 361/13, 361/2, 361/8
• US Class Current: 361/13
• CPC Class Codes: H01H 9/542 Contacts shunted by static switch means

Abstract

A contactor may operate to interrupt current in a circuit while the circuit is operating under load. A shunt is provided to by-pass surge power current around contacts to reduce arcing. The shunt includes a solid-state switch that may be operated in a series of pulses during movement of the contacts. The pulse control unit may detect a potential for arcing and then provide for periodic pulsing operation of the shunt. Because the solid-state switch may operate discontinuously, the contactor may be constructed with a switch that is selected on a basis of its pulse rating.

Claims

1. An electrical power circuit comprising:

a contactor with movable contacts;

an electrical shunt to by-pass current around the contacts; and

a pulse control to;

produce multiple activations of the shunt during movement of the contacts away from each other; and

produce multiple deactivations of the shunt during said movement of the contacts.

2. The contactor of claim 1 wherein the contactor is rated to interrupt current in the circuit when the circuit is supplying power to a load.

3. The contactor of claim 1 wherein the contactor is rated to interrupt short-circuit current in the circuit.

4. The contactor of claim 3 wherein the contactor is rated to interrupt direct current.

5. The contactor of claim 1 wherein the electrical shunt comprises a solid-state switch.

6. The contactor of claim 1 wherein:

the contacts move apart from one another during a first time period;

the shunt is operated in a series of pulsed operations during the first time period; and

none of the pulsed operations extends individually for more than 20% of the first time period.

7. The contactor of claim 6 wherein a cumulative elapsed time for all of the pulsed operation does not exceed 50% of the first time period.

8. The contactor of claim 6 wherein none of the pulsed operations is performed for more than 20 microseconds (μ

sec) or less than 1 μ

sec.

9. A method for interrupting current in a circuit under load conditions comprising the steps of:

moving conducting contacts away from one another for a predetermined time period;

detecting electrical power at the contacts during the step of moving the contacts;

determining if the detected power is sufficient to initiate arcing at the contacts;

performing multiple operations of an electrical shunt around the contacts during the predetermined time period;

disabling the electrical shunt multiple times during the time period; and

passing power between the contacts during said moving whenever the electrical shunt is disabled.

10. The method of claim 9 wherein:

the step of moving the contacts is performed for a first period of time; and

the step of operating the electrical shunt is performed in at least one pulse having a pulse time period no greater than 20% of the first period of time.

11. The method of claim 9 wherein:

operating the electrical shunt is performed in a series of pulsed operation steps; and

disabling the electrical shunt is performed in a series of pulsed operations intervening the steps of operating the shunt.

12. The method of claim 11 wherein:

the step of moving the contacts is performed for a surge period of time; and

pulsed operations of the shunt are performed in pulses of no more than 20% of the surge period.

13. The method of claim 9 wherein:

the step of operating the shunt comprises closing a solid-state switch; and

the step of operating the shunt is completed within a time that does not exceed a time period on which a pulse-rating of the switch is based.