US3820046A

US3820046A - Auxiliary switch for molded-case circuit breaker

Info

Publication number: US3820046A
Application number: US00406729A
Authority: US
Inventors: B Layton; W Weaver
Original assignee: Square D Co
Current assignee: Schneider Electric USA Inc
Priority date: 1973-10-15
Filing date: 1973-10-15
Publication date: 1974-06-25
Anticipated expiration: 1991-06-25

Abstract

A molded-case circuit breaker is provided with a separate compartment containing an auxiliary switch. The switch may be constructed and arranged to be in an open condition when the circuit breaker is ON, and connected in series with a remote warning device activated upon tripping of the circuit breaker and closing of the switch, or it may be constructed and arranged to be in a closed condition when the circuit breaker is ON, and connected in series with a remotely energizable shunt trip coil provided in the separate compartment and deenergized upon tripping of the circuit breaker and opening of the switch.

Description

United States Patent [191 Layton et al.

[in 3,820,046 [4 June 25, 1974 AUXILIARY SWITCH FOR MOLDED-CASE CIRCUIT BREAKER [75] Inventors: Beryl W. Layton; William J.

Weaver, both of Cedar Rapids, Iowa [73] Assignee: Square D Company, Park Ridge, Ill. [22] Filed: Oct. 15, 1973 [2i] Appl. No.: 406,729

52 US. Cl. 335/13, 335/25 [51] Int. Cl. HOlh 71/46 [58] Field of Search 335/13, 17, 25

[56] References Cited UNITED STATES PATENTS 3,264,428 8/1966 Hollyday 335/25 3,340,375 9/1967 Kiesel et al. 335/17 3,436,695 4/1969 Dessert..... 335/13 3,530,412 9/1970 Gryctko.... 335/13 Primary Examiner-Harold Broome Attorney, Agent, or Firm-Harry G. Thibault; Harold J. Rathbun 5 7] ABSTRACT A molded-case circuit breaker is provided with a separate compartment containing an auxiliary switch. The switch may be constructed and arranged to be in an open condition when the circuit breaker is ON, and connected in series with a remote warning device activated upon tripping of the circuit breaker and closing of the switch, or it may be constructed and arranged to be in a closed condition when the circuit breaker is ON, and connected in series with a remotely energizable shunt trip coil provided in the separate compartment and deenergized upon tripping of the circuit breaker and opening of the switch.

5 Claims, 11 Drawing Figures PATENTEDJUNZS m4 SHEET 3 0F 4 FIG.IO

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PATENTEDJUH 25 I974 SHEET UF 4 AUXILIARY SWITCH FOR MOLDED-CASE CIRCUIT BREAKER This invention relates to an auxiliary switch for a molded-case circuit breaker. In the preferred embodiment, the switch is closed when the circuit breaker is ON, is connected in series with a shunt trip coil, and is opened upon tripping of the circuit breaker. If tripping of the circuit breaker is the result of persistent conditions which would cause continuous energization of the shunt trip coil, the opening of the auxiliary switch would prevent the coil from burning out. In a modified version, the switch is open when the circuit breaker is ON, is connected in series with a remote warning device, and is closed upon tripping of the circuit breaker.

A principal object of the invention is to provide an auxiliary switch as protection means for a shunt trip coil of a molded-case circuit breaker.

Other objects and advantages will become apparent when the following specification is considered along with the accompanying drawings in which:

FIG. 1 is an end elevational view of a single-pole molded-case electric circuit breaker constructed in accordance with the invention and including a separate compartment for auxiliary devices;

FIG. 2 is a sectional view taken generally along the line 2-2 of FIG. 1 and showing a circuit breaker mechanism in an ON condition;

FIG. 3 is a sectional view taken generally along the line 3-3 of FIG. 1 and showing-a partition wall between compartments;

FIG. 4 is a sectional view taken generally along the line4-4 of FIG. 1 and showing auxiliary devices in the separate compartment;

FIG. 5 is a fragmentary perspective view of portions of an auxiliary switch of FIG. 4, taken generally in the direction of arrows 5-5;

FIG. 6 is a fragmentary sectional view taken generally along the'line 6-6 of FIG. 4 and showing an end portion of a shunt trip coil and an actuating core member;

FIG. 7 is a perspective view, with portions broken away, of certain parts of FIG. 6;

FIG. 8 is a front view of a modified single-pole molded-case electric circuit breaker constructed in accordance with the invention and including a separate compartment for auxiliary devices;

FIG. 9 is a sectional view taken along the line 9-9 of FIG. 8 and showing auxiliary devices in the separate compartment;

FIG. 10 is a fragmentary sectional view showing a modification of the auxiliary switch of FIG. 4; and

FIG. 11 is a fragmentary perspective view of portions of the auxiliary switch of FIG. 10.

In accordance with the invention and as shown in FIG. 1, a casing portion forms a separate compartment for auxiliary devices and a casing portion 22 houses a single-pole circuit breaker having a mechanism similar to that shown in U.S. Pat. No. 2,902,560, to which reference may be had for a more complete description. The present invention is not confined to single pole circuit breakers but may also be incorporated in multi-pole molded-case electric circuit breakers such as disclosed in US. Pat. No. 2,889,428.

The circuit breaker mechanism of the casing portion 22 is shown in FIG. 2 and includes a plug-in type line terminal member 28 having a stationary contact 29 secured to an inner end portion thereof, a pivotally mounted reciprocable operating handle 30, a movable contact arm 32 pivotally mounted adjacent one end in a pair of spaced depending leg portions of the handle 30 and having a movable contact 33 adjacent the other end, a releasably latchable trip lever 34 pivotally mounted on a pin portion 35 of the casing portion 22, a tension spring 36 connected adjacent one end to the contact arm 32 and adjacent the other end to the trip lever 34, a load terminal strap 38 provided with a clamping screw 39, a bi-metallic strip 40 attached adjacent one end to an inner end of the strap 38 and having a generally U-shaped magnetizable core 42 secured to its other end portion, a braided conductor 44 having one end portion secured between the bi-metallic strip 40 and the core 42 and its other end portion secured to the contact arm 32, an armature member 46 pivotally mounted on the core 42 and releasably latching the trip lever 34, a compression spring 48 biasing the annature 46 away from the core 42, a generally U-shaped ambient temperature compensating bimetallic member 50 having one leg portion secured to the armature 46 and its other leg portion loosely overlapping the core 42, a calibrating screw 52 for resiliently deforming the terminal strap 38 to vary the amount of latching engagement between the trip lever 34 and the armature 46, a mounting clip 54 opposite the line terminal 28, a stack 56 of arc suppressing plates adjacent the contacts 29 and 33, an arc shield 58 of insulating material hooked to the movable contact arm 32, a pin 60 carried by the trip lever 34 and cooperable with the handle 30 to effect the relatching of the trip lever, and a bent tab portion 62 of the trip lever 34 adjacent a pivotally mounted trip bar 76 and an armature actuating first crank member 66 when the trip lever is in a latched position, and engageable, on movement of the trip lever away from the latched position, with an outer end portion of the first crank member 66. The tab 62 also retains a biasing spring 68 connected to an indicating member 70, the indicator 70 being movable into an exposed position with respect to a viewing window 72 in an upper wall of the casing portion 22 when the trip lever 34 is moved to the tripped position.

On the flow of a sustained moderate overload current through the bimetallic strip 40 of the circuit breaker mechanism of the casing portion 22, deflection thereof causes counterclockwise (as viewed in FIG. 2) movement of the core 42, ambient temperature compensating member 50, and armature 46 about the upper end of the bimetallic strip 40 and releases the trip lever 34. Also, upon flow of a high fault current through the bimetallic strip 40 of the circuit breaker mechanism, the armature 46 is attracted toward the core 42 and releases the trip lever 34. The trip lever 34 of the circuit breaker mechanism is thus provided with a thermally and magnetically responsive tripping means including the bimetallic strip 40, core 42, armature 46, and bimetallic member 50.

The casing portion 20 is connected to the casing portion 22, with an intermediate wall portion 24 therebetween, by appropriate fastening means and the compartments in the two casing portions are traversed by the trip bar 76 on which the first crank member 66 in the casing portion 22 and a second crank member 66 in the casing portion 20 are mounted.

The release of the trip lever 34 of the circuit breaker mechanism, biased clockwise (as viewed in FIG. 2) by the spring 36, causes movement of the upper end of spring 36 to the opposite side of the pivotal connection between the contact arm 32 and the handle 30, to effect disengagement of the movable contact 33 from the stationary contact 29. The release of the trip lever 34 also causes movement of the tab 62 into engagement with the first crank member 66 to effect pivotal movement thereof counterclockwise (as viewed in FIG. 2), and, through the trip bar 76, to also effect pivotal movement of the second crank member 66in the casing portion 20.

As shown in FIG. 4, the casing portion forms a compartment for electromagnetically operable actuating means for effecting movement of the latching armature member 46 to release the trip lever 34 of the circuit breaker mechanism of the casing portion 22, the actuating means including a generally U-shaped magnetizable frame 82 having a bight portion 82a and a pair of spaced parallel leg portions 82b and 820. A solenoid or trip coil 84 mounted within the frame 82 has a reciprocable actuating core member 85. Mounted opposite the bight portion 82a adjacent the free end portions of the leg portions 82b and 820 is a guide plate 86 having an opening therein which receives one end of the core member 85. An opposite end of the core member 85 passes through a hole in the bight portion 82a of the frame 82. An elongated actuating tab 87 is suitably secured to the end of the core member passing through the bight portion of the frame 82, as by a rivetlike portion 88 best shown in FIG. 7. A biasing spring 89 mounted in the casing portion 20 biases the actuating tab 87 and core member 85 toward the right in FIG. 4. The free end portion of the tab 87 extends through an opening 79 (FIG. 3) in the intermediate wall portion 24 into cooperative relationship with the ambient temperature compensating bimetallic member 50, which is connected to the armature 46. When the trip coil 84 is energized, the tab 87 strikes the bimetallic member 50 to drive the armature 46 toward the core 42 and release the trip lever 34 to trip the circuit breaker mechanism of the casing portion 22. The end of the core member 85 adjacent the guide plate 86 has a peripheral ring 85a to limit its travel.

Terminals 90 and 91 on the casing portion 20 are connectable to an external circuit for energizing the coil 84. Thus the coil 84 can be energized from a remote location to trip the circuit breaker mechanism of the casing portion 22.

In accordance with this invention, the casing portion 20 has a switch 92 provided therein as shown in the upper right-hand comer of FIG. 4 and in FIG. 5. The switch 92 comprises a pair of contacts in the form of flexible resilient contact fingers 93 and 94 which are normally open. A switch operating member or lever 95 includes a triangular plate 96 having an upper surface and a lower surface (the terms upper and lower referring specifically to the orientation of the plate 96 as shown in FIG. 5), a driving pin 96a extending perpendicularly from the upper surface of the plate 96 at one of the vertices thereof, and a switch operating pin 96b and a mounting pin 96c extending respectively from the lower surface of the plate 96 at the remaining two vertices thereof. The mounting pin 96c is pivotally mounted in a hole 98 in the casing portion 20. The switch operating pin 96b is engageable with the contact finger 93 of the switch 92. The driving pin 96a extends through a hole 99 (FIG. 3) in the intermediate wall portion 24 and is engageable with a surface 97 (FIG. 2) of the operating handle 30 of the circuit breaker mechamsm.

When the circuit breaker handle is moved to the ON position, the driving pin 96a cooperates with the surface 97 of the operating handle 30 of the circuit breaker to pivot the plate 96 counterclockwise about the mounting pin 960 as viewed in FIGS. 4 and 5, the switch operating pin 96b moving contact finger 93 into engagement with the contact finger 94. Thus, when the circuit breaker handle 30 is in the ON position, the switch 92 is closed. 7

With the switch 92 closed, a current path exists from the terminal 91, through the contact fingers of the switch 92 and the coil 84 to the terminal 90. When a circuit is completed at a remote location, current flow through the coil 84 actuates the core member to cause the tab 87 to push the bimetallic member 50 and drive the armature 46 of the circuit breaker mechanism of the casing portion 22 toward the core 42 to release the trip lever 34.

The release of the trip lever 34 causes movement of the tab 62 into engagement with the first crank member 66 of the circuit breaker 22 to affect pivotal movement thereof counterclockwise as viewed in FIG. 2. The movement of the first crank member 66 is transmitted through the trip bar 76 to effect pivotal movement of the second crank member 66 in the casing portion 20 clockwise as viewed in FIG. 4, moving the second crank member 66 into engagement with the contact finger 94 of the switch 92 and moving the contact finger 94 out of engagement with the contact finger 93 to hold the switch open when the circuit breaker mechanism of the casing portion 22 is in the tripped condition. Thus the switch 92 is held open by the second crank member 66 when the circuit breaker is in the tripped condition and the switch 92 remains open regardless of the position of the switch operating lever 95.

A second embodiment of the present invention is disclosed in FIGS. 8 and 9 in which a casing portion 101, a wall portion 102, and a casing portion 103 are secured together. The casing portion 103 houses a circuit breaker mechanism such as that disclosed in U.S. Pat. No. 3,061,697. The casing portion 101 has a switch 104 therein having normally

open contacts

108 and 109. A switch operating lever 110 includes a plate 111 having a front surface and a rear surface (the terms front and rear refer specifically to the orientation of the lever as shown in FIG. 9), a driving pin 111a extending perpendicularly from the front surface of the plate 111 at a vertex thereof, and a switch operating pin lllb and a mounting pin lllc extending from the rear surface of the plate 111 at respective vertices thereof. The mounting pin lllc is pivotally mounted in a hole in the casing portion 101. The switch operating pin lllb is engageable with the contact 108 of the switch 104. The driving pin 111a extends through an opening (not shown) in the wall portion 102 to engage a surface of one of a pair of toggle links (not shown) of the operating mechanism of the circuit breaker in the casing portion 103.

When the circuit breaker handle is moved to the ON position, the driving pin 111a cooperates with the toggle link of the circuit breaker mechanism in the casing portion 103 to pivot the plate 111 about the mounting pin lllc, the switch operating pin 11 1b moving the contact 108 into engagement with the contact 109 to close the switch 104. Thus when the handle of the circuit breaker in the casing portion 103 is in the ON position, the switch 104 is closed.

With the switch 104 closed, a current path exists from a terminal 112 on the casing portion 101, through the switch 104 and a coil 115, to a second terminal 114 on the casing portion 101. When a circuit is completed at a remote location, current flow through the coil 115 actuates a reciprocable actuating core member 116 which unlatches a trip lever (not shown) of the circuit breaker in the casing portion 103 to mechanically trip the circuit breaker in a manner similar to that described above for the circuit breaker in the casing portion 22.

When the circuit breaker in the casing portion 103 is mechanically tripped, a trip bar 117, similar to the trip bar 76 in the

casing portions

20 and 22, is pivotally rotated to effect pivotal movement of a crank member 118 in the casing portion 101. The pivotal movement of the crank member 118 moves the contact 109 out of engagement with the contact 108 and holds the switch open when the circuit breaker in the casing portion 103 is in the tripped condition. Thus the switch 104 is held open by the crank member 118 when the circuit breaker is in the tripped condition and the switch 104 remains open regardless of the position of the switch operating lever 110.

The switch actuating levers 95 and 110 may also be used to operate auxiliary switches similar to the

switches

92 and 104 but modified to activate an alarm, in a system without a shunt trip coil, as a signal that the circuit breaker is OFF or TRIPPED. Such a modified switch 120 is shown in FIGS. and 11 in conjunction with the switch operating lever 95. The switch 120 includes a pair of flexible

resilient contact fingers

122 and 124, the contact 124 having a generally U-shaped free end portion including a leg portion 125 and the free end portion of the contact 122 being disposed within the U-shaped portion of the contact 124 and normally engaging the inner side of the leg portion 125.

Operation of the switch 120 is as follows. When the circuit breaker is closed to ON condition, the driving pin 96a of the lever 95 is driven by the surface 97 (FIG. 2) on the breaker handle 30, which causes the switch operating pin 96b to deflect the contact 122 away from the leg portion 125 of the contact 124, thus opening the switch 120. When the circuit breaker is tripped, the crank member 66 pushes the contact 124 downwardly as viewed in FIG. 10 to re-establish contact between the leg portion 125 and the contact 122, which closes the switch 120 to complete an alarm circuit, regardless of the position of the lever 95. When the circuit breaker is reset and left in OFF condition, the lever 95 is returned to its normal position by the resiliency of the contact 122, allowing the contact 122 to resume its normal engagement with the leg portion 125 of the contact 124, which also closes the switch 120 to complete an alarm circuit.

The switch 120 could be designed to be closed only when the circuit breaker of the casing portion 22 is in the tripped condition. The contact 122 could be formed so that in its normal or free position it would not touch any part of the contact 124, particularly the leg portion 125, and the switch lever 95 could be omitted. Then the operation of the switch would consist only of the crank member 66 pushing the contact 124 downwardly as viewed in FIG. 10 when the breaker trips. This would cause the contact 122 to engage the leg portion 125 of the contact 124, closing the switch 120. In ON and OFF conditions of the circuit breaker, there would be no contact between

contacts

122 and 124.

Various modifications may be made in the structure disclosed without departing from the spirit and scope of the invention as set forth in the appended claims.

We claim:

1. An electric circuit breaker comprising:

a. a molded case having a plurality of compartments;

b. a circuit breaker mechanism in one of the compartments including a pair of separable contacts, a releasably latchable trip lever releasable from a latched position to effect separation of the contacts, and thermally and electromagnetically operable tripping means operable to effect release of the trip lever and separation of the contacts;

c. an operating handle pivotally mounted in the case, operatively connected to the contacts, and movable to an ON position to close the contacts and to an OFF position to open the contacts;

d. an auxiliary switch including a pair of resiliently flexible contact fingers disposed in another of the compartments and having one operating condition in which the contact fingers are in engagement with each other and another operating condition in which the contact fingers are out of engagement with each other;

. a switch operating member pivotally mounted in said other of the compartments, operatively engaged with a first of the contact fingers, and operatively engageable with the operating handle;

f. a trip bar mounted for pivotal movement in the case and traversing the compartments;

g. a first crank member mounted on the trip bar in said one of the compartments for rotary movement unitarily therewith upon operation of the tripping means; and

h. a second crank member mounted on the trip bar in said other of the compartments for rotary movement unitarily therewith and operatively engageable with a second of the contact fingers, the first contact finger being flexed by the switch operating member to place the auxiliary switch in one of the operating conditions upon movement of the operating handle to the ON position, and the second contact finger being flexed by the second crank member to place the auxiliary switch in the other of the operating conditions upon operation of the tripping means.

2. An electric circuit breaker as claimed in claim 1 wherein the contact fingers are constructed and arranged in a manner such that the switch operating member flexes the first contact finger out of engagement with the second contact finger upon movement of the operating handle to ON position and the second crank member flexes the second contact finger into engagement with the first contact finger upon operation of the tripping means.

3. An electric circuit breaker as claimed in claim 1 wherein the contact fingers are constructed and arranged in a manner such that the switch operating member flexes the first contact finger into engagement the tripping means in said one of the compartments.

5. An electric circuit breaker as claimed in claim 1 wherein the switch operating member includes a plate portion having a driving pin extending from one side into operative engagement with the operating handle, and a mounting pin and a switch operating pin extending from the other side, the mounting pin being pivotally mounted in the case and the switch operating pin being operatively engaged with the first contact finger. k

Claims

1. An electric circuit breaker comprising: a. a molded case having a plurality of compartments; b. a circuit breaker mechanism in one of the compartments including a pair of separable contacts, a releasably latchable trip lever releasable from a latched position to effect separation of the contacts, and thermally and electromagnetically operable tripping means operable to effect release of the trip lever and separation of the contacts; c. an operating handle pivotally mounted in the case, operatively connected to the contacts, and movable to an ON position to close the contacts and to an OFF position to open the contacts; d. an auxiliary switch including a pair of resiliently flexible contact fingers disposed in another of the compartments and having one operating condition in which the contact fingers are in engagement with each other and another operating condition in which the contact fingers are out of engagement with each other; e. a switch operating member pivotally mounted in said other of the compartments, operatively engaged With a first of the contact fingers, and operatively engageable with the operating handle; f. a trip bar mounted for pivotal movement in the case and traversing the compartments; g. a first crank member mounted on the trip bar in said one of the compartments for rotary movement unitarily therewith upon operation of the tripping means; and h. a second crank member mounted on the trip bar in said other of the compartments for rotary movement unitarily therewith and operatively engageable with a second of the contact fingers, the first contact finger being flexed by the switch operating member to place the auxiliary switch in one of the operating conditions upon movement of the operating handle to the ON position, and the second contact finger being flexed by the second crank member to place the auxiliary switch in the other of the operating conditions upon operation of the tripping means.

3. An electric circuit breaker as claimed in claim 1 wherein the contact fingers are constructed and arranged in a manner such that the switch operating member flexes the first contact finger into engagement with the second contact finger upon movement of the operating handle to ON position and the second crank member flexes the second contact finger out of engagement with the first contact finger upon operation of the tripping means.

4. An electric circuit breaker as claimed in claim 3 including a shunt trip coil in said other of the compartments and an actuating core member disposed within the coil and mounted for reciprocal movement, the coil being serially connected to the auxiliary switch and the actuating core member being operatively connected to the tripping means in said one of the compartments.

5. An electric circuit breaker as claimed in claim 1 wherein the switch operating member includes a plate portion having a driving pin extending from one side into operative engagement with the operating handle, and a mounting pin and a switch operating pin extending from the other side, the mounting pin being pivotally mounted in the case and the switch operating pin being operatively engaged with the first contact finger.