CA1253550A

CA1253550A - Circuit breaker trip indication device

Info

Publication number: CA1253550A
Application number: CA000486036A
Authority: CA
Inventors: Tony Kranendonk; David A. Dumouchelle; John L. Jones
Original assignee: Westinghouse Canada Inc
Current assignee: Westinghouse Canada Inc
Priority date: 1985-06-28
Filing date: 1985-06-28
Publication date: 1989-05-02
Also published as: ZA864208B; AU5828086A

Abstract

Abstract A moulded case circuit breaker is provided with a trip detector by enclosing a microswitch within the moulded case but out of the path of the operating mechanism. An L shaped operator for the microswitch has one leg which operates the microswitch and the other leg in the path of the trip mechanism of the breaker so that the microswitch is operated when the breaker is tripped.

Description

5i50 CIRCUIT BREAKER TRIP INDICATION DEVICE
BACKGROUND OF THE INVENTION
This invention relates generally to improvements in electrical circuit breakers of the moulded case type and more particularly to an arrangement for indicating tripping or a tripped condition of such a circuit breaker.
.~oulded circuit breakers are well known and typical of such a circuit breaker is the breaker illustrated and claimed in Canadian Patent No. 1,125,856 issued 82/06/15. The circuit breaker as illustrated in the above patent and generally well known, consists of a movable contact mounted on a movable arm and a rigidly mounted stationary contact. The movable arm is normally rotated between a closed and open position by means of a handle. The operating linkage which connects the handle to the movable contact is a collapsible to~gle assembly. ~n electrothermalmagnetic device in the breaker responds to pre-determined electrical conditions and permits the toggle assembly to collapse and the contacts to trip open.
When such toggle mechanism is collapsed and the breaker is in the tripped position it is desirable, in some circumstances, that a signal be provided at a remote location indicating that the breaker has been tripped. Such remote indication of a tripped condition has been provided in the past in large circuit breakers and also has been provided in small circuit breakers by means of separate add-on devices which are associated with the circuit breaker.
BRIEF SUMMARY OF THE INVENTION
The present invention applies to a circuit breaker of the type disclosed in Canadian Patent No. 1,125,~56 and provides an indication of the tripped condition of the breaker without additional equipment external of the breaker and without modification of the normal circuit breaker enclosure.
In accordance with the present invention, these objects are attained by includin~, within the moulded case of the breaker, a small microswitch which intercepts a portion of the cradle when

2 CW 1104 the cradle is in a tripped condition.
A clearer understanding of our invention may be had from a consideration of the following description and drawings in which:
Figure 1 shows a circuit breaker incorporating the lnvention with the circuit breaker in the latched position.
Figure 2 shows the same circuit breaker shown in a tripped condition.
Considering first Figure 1, there is shown a circuit breaker comprising a moulded plastic enclosure 4, a handle 5, fixed contact 6, movable contact 7 mounted on an arm 8 which in turn is pivoted on handle 5. The toggle mechanism for the breaker includes the cradle 9 and the arm 8 which are resiliently connected one to the other by spring 11. Cradle 9 is normally restrained from rotation about its pivot 10 by the engagement with latch 12 which is a portion of the electromechanical trip mechanism.
Details of the trip mechanism and the to~gle will not be provided since they are well known in the art and are disclosed, in particular, in Canadian Patent No. 1,125,856. A microswitch 13 is mounted in a cavity in the moulded housing of the breaker in such a manner as not to interfer with any operating portion of the breaker. An arm 14 on the microswitch is arranged in the path of the flat portion 17 formed by the offset of the cradle 9. As will be seen in Figure 2, in the tripped position the cradle 9 is released from the latch 12 and rotates downwards about its pivot 10 and the flat portion 17 engayes the arm 14 causing the micro-switch 13 to be actuated. Suitable leads, 15, 16 and 18 for normally open and/or closed configurations extend from the micro-switch out through a suitable aperture in the housing and may be used to actuate any indicator such as a lamp or alarm which will indicate the tripping of the breaker.
As will be seen from Figure 2, the microswitch 13 is operated only when the cradle 9 is rotated and therefore is actuated only when the breaker is tripped. When the breaker is manually operated from an on to an off position, the cradle remains in its counter clockwise rotated position, that is in its latched position.

1'~5~5~

3 CW 1104 Because of the dimens:ions and the location of the microswitch, it is practical to include the microswitch within the moulded case of the breaker and thus the breaker can be inserted in its normal location in a panel board or other enclosure which has been designed for standard breakers.
While the invention has been illustrated in conjunction with a par.ticular type of moulded case circuit breaker, it will be evident that it is applicable to any moulded case breaker which is tripped by means of movement of a member similar to cradle 9 and in which sufficient space is available within the enclosure to permit mounting of the microswitch.

Claims

CLAIMS:

1. A moulded case circuit breaker comprising:
(a) a fixed contact mounted on the case;
(b) a movable contact mounted on an arm;
(c) an operator connected said arm for moving said movable contact from an "open" to "closed" position;
(d) a toggle mechanism including a cradle latched by a trip mechanism and holding said moving contact in said "closed" position when said cradle is latched and releasing said contact to said "open" position when said cradle is unlatched;
(e) a switch mounted wholly within the moulded case of said breaker including an operator arranged in the path of said cradle and contacted by said cradle when said cradle moves to its unlatched position;
(f) leads extending from said switch through said casing for connection to a switch condition indicating device.

2. A moulded case circuit breaker as claimed in claim 1 wherein said cradle is pivotally mounted at one of its ends and is latched by a trip mechanism at its other end and is resiliently connected to said arm.

3 A moulded case circuit breaker as claimed in claim 2 wherein said cradle includes an offset producing a flat portion transverse to the plane of rotation of said cradle about its pivotal mounting.

4. A moulded case circuit breaker as claimed in claim 3 wherein said flat portion of said cradle contacts said operator when said cradle rotates about its pivotal mounting into its unlatched position.

5. A moulded case circuit breaker as claimed in claim 1 or 4 wherein said switch is mounted to one side of the plane of rotation of said cradle and said operator is "L" shaped with one leg of the "L" projecting into the plane of rotation of said cradle.

6. A moulded case breaker as claimed in claim 1 or 4 in which said switch is a microswitch.

7. A moulded case breaker as claimed in claim 1 or 4 in which said switch includes normally open and normally closed contacts.

8. A moulded case breaker as claimed in claim 1 or 4 in which said leads are connected to indicator lamps to indicate the condition of said breaker.

9. A moulded case circuit breaker including a trip detector comprising a microswitch within the moulded case of said breaker and out of the path of the operating portions of said breaker, an operator for said microswitch including a portion which projects into the operating path of the trip mechanism of said breaker and operates said microswitch when engaged by said trip mechanism.