Transfer switch and power system including the same

• US 20060221533A1
• Filed: 04/05/2005
• Published: 10/05/2006
• Est. Priority Date: 04/05/2005
• Status: Active Grant

• Current Assignee: Eaton Corp. (Wisconsin) (Eaton Corporation PLC.)
• Original Assignee: Eaton Corp. (Wisconsin) (Eaton Corporation PLC.)
• Inventors: Lathrop, Todd M., Berad, Derrick G.
• Granted Patent: US 7,336,003 B2
• Time in Patent Office: Days
• US Class Current: 361/160
• CPC Class Codes: H02J 2310/60 Limiting power consumption in the network or in one section of the network, e.g. load shedding or peak shaving
• CPC Class Codes: H02J 3/14 by switching loads on to, or off from, network, e.g. progressively balanced loading
• CPC Class Codes: Y02B 70/3225 Demand response systems, e.g. load shedding, peak shaving
• CPC Class Codes: Y04S 20/222 Demand response systems, e.g. load shedding, peak shaving

Abstract

A transfer switch includes first terminals adapted to input power from a first power source, second terminals adapted to input power from a second power source, third terminals adapted to output power to a first load, and a transfer mechanism adapted to selectively electrically connect the one of the first or second terminals to the third terminals. A control mechanism cooperates with the first and second terminals and the transfer mechanism to electrically connect one of the first and third terminals or the second and third terminals. A control circuit and a relay include normally closed contacts and normally open contacts. The relay is de-energized responsive to the first and third terminals being electrically connected, and energized responsive to the second and third terminals being electrically connected. The normally closed contacts shed corresponding second loads and the normally open contacts enable corresponding third loads when the relay is energized.

Claims

1. A transfer switch comprising:

first terminals adapted to input power from a first power source;

second terminals adapted to input power from a second power source;

third terminals adapted to output power to a first load;

a transfer mechanism adapted to selectively electrically connect either said first terminals or said second terminals to said third terminals; and

a control mechanism cooperating with said first terminals, said second terminals and said transfer mechanism to cause said transfer mechanism to electrically connect one of;

said first terminals to said third terminals or said second terminals to said third terminals, said control mechanism comprising a control circuit and a relay including at least one normally closed contact and at least one normally open contact, said relay being de-energized by said control circuit responsive to said first terminals being electrically connected to said third terminals, said relay being energized by said control circuit responsive to said second terminals being electrically connected to said third terminals, said at least one normally closed contact being adapted to shed a corresponding at least one second load when said relay is energized, and said at least one normally open contact being adapted to enable a corresponding at least one third load when said relay is energized.

2. The transfer switch of claim 1 wherein said relay is a first relay;

wherein said first terminals have a first voltage;

wherein said second terminals have a second voltage; and

wherein said control circuit further comprises a second relay adapted to be energized by the first voltage of said first terminals, a third relay including a normally open contact and a first solenoid, said second relay including a first normally closed contact electrically connected in series with said third relay, said third relay being adapted to be energized by the second voltage of said second terminals when said second relay is de-energized and said first normally closed contact thereof is closed, said first solenoid being energized when a second normally closed contact of said second relay is closed and the normally open contact of said third relay is closed, said first solenoid including an auxiliary switch contact adapted to energize said first relay from the second voltage of said second terminals after said second terminals are electrically connected to said third terminals.

3. The transfer switch of claim 2 wherein said control circuit further comprises a second solenoid adapted to be energized from the first voltage of said first terminals to cause said transfer mechanism to electrically connect said first terminals to said third terminals, and adapted to be de-energized responsive to presence of said second voltage and absence of said first voltage;

and wherein said first solenoid is energized to cause said transfer mechanism to electrically connect said second terminals to said third terminals.

4. The transfer switch of claim 1 wherein said at least one normally closed contact includes four normally closed contacts;

wherein said at least one normally open contact includes four normally open contacts; and

wherein each pair of said normally closed contacts and said normally open contacts is structured as a form C contact.

5. The transfer switch of claim 1 wherein said first terminals have a voltage;

and wherein said control mechanism further comprises fourth terminals electrically interconnected with said first terminals;

in order to output the voltage of said first terminals to said second power source.

6. The transfer switch of claim 5 wherein at least one of said first and second power sources is a voltage sensing generator power source adapted to input the voltage from said fourth terminals and start a generator responsive to said voltage.

7. The transfer switch of claim 6 wherein one of said first and second power sources is said voltage sensing generator power source.

8. The transfer switch of claim 6 wherein each of said first and second power sources is one of said voltage sensing generator power source.

9. The transfer switch of claim 1 wherein said first power source is a utility power source.

10. A transfer switch for a first power source and a second power source, said transfer switch comprising:

first terminals adapted to input power from said first power source, said first terminals having a voltage with a magnitude;

second terminals adapted to input power from said second power source;

third terminals adapted to output power to a load;

fourth terminals adapted to output the voltage of said first terminals to said second power source;

a transfer mechanism adapted to selectively electrically connect either said first terminals or said second terminals to said third terminals; and

a control mechanism cooperating with said first terminals, said second terminals and said transfer mechanism to cause said transfer mechanism to electrically connect one of;

said first terminals to said third terminals or said second terminals to said third terminals,

wherein at least one of said first and second power sources is a voltage sensing generator power source adapted to input the voltage from said fourth terminals and start a generator responsive to the magnitude of said voltage being below a predetermined value.

11. The transfer switch of claim 10 wherein one of said first and second power sources is said voltage sensing generator power source.

12. The transfer switch of claim 10 wherein each of said first and second power sources is one of said voltage sensing generator power source.

13. The transfer switch of claim 10 wherein said first power source is a utility power source.

14. A power system comprising:

a first power source;

a second power source comprising a voltage sensing circuit and a generator power source, said voltage sensing circuit being adapted to input a voltage and start said generator power source responsive to said voltage; and

a transfer switch comprising;

first terminals structured to input power from said first power source, said first terminals having said voltage,

second terminals structured to input power from said second power source,

third terminals adapted to output power to a load,

fourth terminals outputting the voltage of said first terminals to the voltage sensing circuit of said second power source,

a transfer mechanism adapted to selectively electrically connect either said first terminals or said second terminals to said third terminals, and

a control mechanism cooperating with said first terminals, said second terminals and said transfer mechanism to cause said transfer mechanism to electrically connect one of;

said first terminals to said third terminals or said second terminals to said third terminals.

15. The power system of claim 14 wherein said first power source is a utility power source.

16. The power system of claim 14 wherein said fourth terminals are electrically interconnected with said first terminals.

17. The power system of claim 14 wherein said fourth terminals include a first termination and a second termination;

wherein said first terminals include a first termination and a second termination;

wherein the first termination of said fourth terminals is electrically connected to the first termination of said first terminals by a first fuse; and

wherein the second termination of said fourth terminals is electrically connected to the second termination of said first terminals by a second fuse.

18. The power system of claim 14 wherein said control mechanism includes a neutral terminal;

and wherein the voltage of said first terminals includes a line voltage referenced to said neutral terminal.

19. The power system of claim 14 wherein the voltage of said first terminals includes a first line voltage of a first one of said first terminals and an opposite second line voltage of a second one of said first terminals.