Electrical switching apparatus and trip unit including one or more fuses

• US 7,323,956 B1
• Filed: 07/29/2005
• Issued: 01/29/2008
• Est. Priority Date: 07/29/2005
• Status: Active Grant

• Current Assignee: Eaton Intelligent Power Limited (Eaton Corporation PLC.)
• Original Assignee: Eaton Corp. (Wisconsin) (Eaton Corporation PLC.)
• Inventors: Puskar, Michael P., Mueller, Robert W., Stay, Amelia M., Beatty, William E. Jr.
• Primary Examiner(s): Barrera; Ramon M.
• Application Number:
  US11/194,081
• Time in Patent Office: 914 Days
• Field of Search: 335 6- 11, 335 21- 23, 335 35- 37, 335/43, 335/172, 337 6- 7
• US Class Current: 335/6
• CPC Class Codes: H01H 2085/0233 with common casing for fusible elements inserted in more than one phase or more than one circuit
• CPC Class Codes: H01H 71/122 actuated by blowing of a fuse

Abstract

A circuit breaker includes a circuit breaker frame and a trip unit. The circuit breaker frame includes a housing, a line terminal, a load terminal, separable contacts electrically connected between the line terminal and the load terminal, an operating mechanism structured to open and close the separable contacts, and a latch cooperating with the operating mechanism to open the separable contacts when actuated. The trip unit includes a housing, a line end terminal electrically connected to the load terminal of the circuit breaker frame, a load end terminal, and a fuse including a plunger. The fuse is housed by the housing of the trip unit and is electrically connected between the line end terminal and the load end terminal. An interface mechanism is structured to actuate the latch of the circuit breaker frame when the interface mechanism is engaged by the plunger of the fuse.

Claims

1. An electrical switching apparatus comprising:

a circuit breaker frame comprising;

a housing,

a line terminal,

a load terminal,

separable contacts electrically connected between said line terminal and said load terminal,

an operating mechanism structured to open and close said separable contacts, and

a latch cooperating with said operating mechanism to open said separable contacts when actuated; and

a trip unit comprising;

a housing,

a line end terminal electrically connected to the load terminal of said circuit breaker frame,

a load end terminal,

a fuse including a plunger, said fuse being housed by the housing of said trip unit and being electrically connected between said line end terminal and said load end terminal, and

an interface mechanism structured to actuate the latch of said circuit breaker frame when said interface mechanism is engaged by the plunger of said fuse,

wherein the housing of said circuit breaker frame includes an opening structured to receive the housing of said trip unit, and

wherein the line end terminal of said trip unit is electrically and mechanically connected to the load terminal of said circuit breaker frame by a fastener which is accessible external to the housing of said circuit breaker frame and the housing of said trip unit when the opening of said circuit breaker frame receives the housing of said trip unit in order that said trip unit which houses said fuse is field mountable or field replaceable.

2. The electrical switching apparatus of claim 1 wherein said trip unit is interchangeable with another trip unit.

3. The electrical switching apparatus of claim 1 wherein the housing of said trip unit substantially encloses said fuse.

4. The electrical switching apparatus of claim 1 wherein the interface mechanism of said trip unit comprises a pivotally mounted trip bar including a tab structured to be engaged by the plunger of said fuse.

5. The electrical switching apparatus of claim 4 wherein the housing of said trip unit includes an opening;

wherein the tab of said pivotally mounted trip bar is a first tab;

wherein said pivotally mounted trip bar further includes a second tab; and

wherein the interface mechanism of said trip unit further comprises a spring-biased plunger structured to pass through the opening of the housing of said trip unit, the second tab of said trip bar normally engaging and holding said spring-biased plunger within the opening of the housing of said trip unit, the second tab of said trip bar releasing said spring-biased plunger in order to actuate the latch of said circuit breaker frame when the plunger of said fuse engages the first tab of said pivotally mounted trip bar and pivots said pivotally mounted trip bar.

6. The electrical switching apparatus of claim 1 wherein the housing of said trip unit includes an opening;

and wherein the interface mechanism of said trip unit further comprises a spring-biased plunger structured to pass through the opening of the housing of said trip unit, in order to actuate the latch of said circuit breaker frame when said interface mechanism is engaged by the plunger of said fuse.

7. The electrical switching apparatus of claim 6 wherein the interface mechanism of said trip unit further comprises a member structured to engage and hold said spring-biased plunger within the opening of the housing of said trip unit until after the plunger of said fuse engages said interface mechanism.

8. The electrical switching apparatus of claim 1 wherein the latch of said circuit breaker frame is a secondary frame latch;

and wherein the interface mechanism comprises a plunger structured to actuate the secondary frame latch of said circuit breaker frame after said interface mechanism is engaged by the plunger of said fuse.

9. The electrical switching apparatus of claim 1 wherein said fuse includes first and second terminals;

wherein the line end terminal of said trip unit is directly electrically connected to the first terminal of said fuse; and

wherein the load end terminal of said trip unit is directly electrically connected to the second terminal of said fuse.

10. A circuit breaker comprising:

a circuit breaker frame comprising;

a housing,

at least one pole comprising;

a line terminal,

a load terminal, and

separable contacts electrically connected between said line terminal and said load terminal,

an operating mechanism structured to open and close said separable contacts, and

a latch cooperating with said operating mechanism to open said separable contacts when actuated; and

a trip unit comprising;

a housing,

at least one pole comprising;

a line end terminal electrically connected to a corresponding load terminal of said circuit breaker frame,

a load end terminal, and

a fuse including a plunger, said fuse being housed by the housing of said trip unit and being electrically connected between said line end terminal and said load end terminal, and

an interface mechanism structured to actuate the latch of said circuit breaker frame after said interface mechanism is engaged by the plunger of said fuse,

wherein the housing of said circuit breaker frame includes an opening structured to receive the housing of said trip unit, and

wherein the line end terminal of said trip unit is electrically and mechanically connected to the load terminal of said circuit breaker frame by a fastener which is accessible external to the housing of said circuit breaker frame and the housing of said trip unit when the opening of said circuit breaker frame receives the housing of said trip unit in order that said trip unit which houses said fuse is field mountable or field replaceable.

11. The circuit breaker of claim 10 wherein the interface mechanism of said trip unit comprises a pivotally mounted trip bar including a tab structured to be engaged by the plunger of said fuse.

12. The circuit breaker of claim 11 wherein the housing of said trip unit includes an opening;

wherein the tab of said pivotally mounted trip bar is a first tab;

wherein said pivotally mounted trip bar further includes a second tab; and

wherein the interface mechanism of said trip unit further comprises a spring-biased plunger structured to pass through the opening of the housing of said trip unit, the second tab of said trip bar normally engaging and holding said spring-biased plunger within the opening of the housing of said trip unit, the second tab of said trip bar releasing said spring-biased plunger in order to actuate the latch of said circuit breaker frame after the plunger of said fuse engages the first tab of said pivotally mounted trip bar and pivots said pivotally mounted trip bar.

13. The circuit breaker of claim 10 wherein the housing of said trip unit includes an opening;

and wherein the interface mechanism of said trip unit further comprises a spring-biased plunger structured to pass through the opening of the housing of said trip unit, in order to actuate the latch of said circuit breaker frame after said interface mechanism is engaged by the plunger of said fuse.

14. The circuit breaker of claim 10 wherein the latch of said circuit breaker frame is a secondary frame latch;

and wherein the interface mechanism comprises a plunger structured to actuate the secondary frame latch of said circuit breaker frame after said interface mechanism is engaged by the plunger of said fuse.

15. A trip unit for a circuit breaker frame including a housing having an opening, a latch and a load terminal, said trip unit comprising:

a housing;

a first terminal structured to be electrically connected to the load terminal of said circuit breaker frame;

a second terminal;

at least one fuse including a plunger, said at least one fuse being housed by said housing and being electrically connected between said first terminal and said second terminal; and

an interface mechanism structured to actuate the latch of said circuit breaker frame when said interface mechanism is engaged by the plunger of said at least one fuse,

wherein the housing of said trip unit is structured to be received by the opening of the housing of said circuit breaker frame, and

wherein the line end terminal of said trip unit is structured to be electrically and mechanically connected to the load terminal of said circuit breaker frame by a fastener which is accessible external to the housing of said circuit breaker frame and the housing of said trip unit when the housing of said trip unit is received by the opening of the housing of said circuit breaker frame in order that said trip unit which houses said fuse is field mountable or field replaceable.

16. The trip unit of claim 15 wherein said interface mechanism comprises a pivotally mounted trip bar including a tab structured to be engaged by the plunger of said at least one fuse.

17. The trip unit of claim 16 wherein said housing includes an opening;

wherein the tab of said pivotally mounted trip bar is a first tab;

wherein said pivotally mounted trip bar further includes a second tab; and

wherein said interface mechanism further comprises a spring-biased plunger structured to pass through the opening of said housing, the second tab of said trip bar normally engaging and holding said spring-biased plunger within the opening of said housing, the second tab of said trip bar releasing said spring-biased plunger in order to actuate the latch of said circuit breaker frame when the plunger of said at least one fuse engages the first tab of said pivotally mounted trip bar and pivots said pivotally mounted trip bar.

18. The trip unit of claim 15 wherein said housing includes an opening;

and wherein said interface mechanism further comprises a spring-biased plunger structured to pass through the opening of said housing, in order to actuate the latch of said circuit breaker frame when said interface mechanism is engaged by the plunger of said at least one fuse.

19. The trip unit of claim 15 wherein the latch of said circuit breaker frame is a secondary frame latch;

and wherein said interface mechanism comprises a plunger structured to actuate the secondary frame latch of said circuit breaker frame after said interface mechanism is engaged by the plunger of said at least one fuse.

20. The trip unit of claim 15 wherein said circuit breaker frame includes three poles;

and wherein said at least one fuse is three fuses.