US3855557A

US3855557A - Test trip means for circuit breaker

Info

Publication number: US3855557A
Application number: US00421032A
Authority: US
Inventors: C Gryctko
Original assignee: ITE Imperial Corp
Current assignee: Siemens Energy and Automation Inc
Priority date: 1973-12-03
Filing date: 1973-12-03
Publication date: 1974-12-17
Anticipated expiration: 1991-12-17
Also published as: CA1019792A

Abstract

A multipole molded case circuit breaker having an individual automatic trip unit for each pole acting through a common trip bar for releasing the contact operating mechanism under predetermined overload conditions is provided with individual rotatable members for calibrating each of the trip units. The rotatable calibrating member of one pole is so constructed that for test purposes, in a predetermined angular position of this calibrating member it may also be depressed to engage a projection of the common trip bar to pivot the latter and release the latch to open the contacts of all phases.

Description

United States Patent 1 1. Gryctko I [54] TEST TRIP MEANS FOR'CIRCUIT BREAKER I [75] Inventor: Carl Gryctko, Haddon Heights,

[73] Assignee: l-T E-linperial Corporation, Spring g House; Pa. 221 Filed:- nec.3,' 1973 211 ApplfNo; 421,032

52 us. ('31.; 335/42, 335/176 51 Int.Cl... H01h71/74' [58] Field of Search.....'.-.. 335/176, 42, 45 [56] ,Reft rences Cited 5 UNITED STATES PATENTS 3,775.713- 1-1 1 973 Walker-etalQ 335/176 1451 Dec. 17, 1974 Primary -Exa r'nine rHa rold Broome Attorney, Agent, 0r*Firm-Ostrolenk, Faber, Gcrb & Soffen 1 1 1. 1 1 1, A R CT A rnultipole molded case circuit breaker having an individual automatic trip unit for each pole acting through a common trip. ba r{for releasing the contact operating mechanism under predetermined overload conditions is provided with individual rotatable members for calibrating each of the trip units. The rotatable calibrating member of'one pole so constructed that for test purposes, in a predeterinined angular position of this calibratingmember it may also be depressed to engage aprojection of the common trip bar to pivot the latter and release thelatch to open the contacts of all phases. l

8 Claims,,4 Drav1/ing Fignres. l

TEST'TRIP MEANS FOR CIRCUIT BREAKER- 3,125,651, issued Mar. 17, 1964, m .l. c. Brumfield, for

a Magnetic Trip Means, illustrates a typical molded case circuit breaker construction in which each pole is provided with a rotatable member operable from outside the circuit breaker to adjust the trip setting of the magnetic trip means. i v

' it is often necessary to test a circuit breaker to determine that its contact operating mechanismwill open the breaker when the automatic tripmeans is actuated. Such a test should be capable of being performed without the necessity-of opening the circuit breaker housing or'inserting a foreign element therein; t

Thus, the instant invention utilizes the rotatable adcontact operating mechanism. More particularly, not

only is the adjusting member rotatable for calibration purposes but it is also depressible. When the adjusting member is rotated to a predetermined angular position, the test position, depressing the member will cause a portion thereof to engage a projection of the common trip bar, thereby rotating the latter to release the latch that normally maintains the contact operating mechanism in reset position. t

Accordingly, a primary object of the instant invention isto provide a novel'construction for a molded case circuit breaker wherein test trip may be accomplished without opening the circuit breaker housing or inserting a foreign object therein.

Another object is to provide a circuit breaker of this type in which test trip is accomplished by utilizing a member that adjusts calibration at one of the, automatic tripping means. v

Still another object is to provide a circuit breaker of this type in which a rotatable calibrating memberoperable from outside of the circuit breaker housing isalso depressible to operate a common trip bar to release the contact operating mechanism.

These objects as well as other objects of the instant invention will become readily apparent after reading ings in which:

FIG. 1 is a longitudinalcross-section of a molded case circuit breaker constructed in accordance with teachings of the instant invention.

FIG. '2 is a cross-section taken through line 22 of FlG. 1, looking in the direction of arrows 2-2.

FIG 3 is a fragmentary plan view looking in the direction of arrows 3-3 of FIG. 1.- 1

FIG. 4 is an exploded perspective of the elements compartments, one for each phase of circuit breaker 10. Similar longitudinal partitions (not shown) are provided for cover '12. I I v The current path through each phase of circuit breaker comprises load terminal connecter 16, load terminal strapyincluding loop portion 18 having por tion 20 of reduced cross sections which serves as a heaterfor bi-rnetal'trip element 21, connecting member 22, flexible member 23 to one end of movable contact arm-24. Movable contact 25 is mounted to the other end of contact arm 24 and is engageable with stationary contact 26 mounted to one end of line terminal strip 27 which is, connected by screw means 29 to tulip connector 28 forming the line terminal connection.

' the following description of the accompanying draw constituting the automatic trip means for one pole of r Trip free operating mechanism 30 is provided to pivot movabletie bar 99 about pin 36. Allthree contact v arms 24 are carried by tie bar 99 for simultaneously operating movable contacts 25 of all three phases into and out of engagement with their associated stationary contacts 26. Operating mechanism 30 is of an overcenter toggle type well known to the art and is fully described in the E. R. 'Wortman U.S. Pat. No. 3,155,802 issued Nov. 3,4964 for UfShaped Cradle for Circuit Breaker. Handle 98 is provided for manual operation of mechanism 30 while overload device 97 is provided for automatictripping of mechanism 30.

Are extinguishing means in the form of arc chute 40 is operatively'positioned by suitable formations in base to receive electric current arcs drawn between

cooperating contacts

25, 26 upon separation thereof. Since the theory ofarc interruption is well understood to those skilled in the art elaboration of this point will not be undertaken atthis time.- V

Overload device 97, in addition to comprising a time delay tripping means comprising bimetal 21 also comprises instantaneous trip means 100. The latter is described in detail in the aforesaid U.S. Pat. No. 3,125,651. Briefly, and with particular reference to FIG. 4, it is seen that'magnetic trip means 100 includes g'enerallyU-shaped magnet pole piece 101 energized by current passing through loop 18. Pole piece 101 is mounted to generally U-shaped frame 102 with the armsof pole piece 101 extending at right angles to the arms of frame 102. One of the arms of frame 102 is provided with upward extension 113 with U-shaped bracket 114 mounted at the upper end thereof by means of slots 115,116 of frame 102, and bracket 114, respectively, which receive

ears

117, 118 of bracket 114 and frame 102, respectively.

Bracket 114 carries rotatable air gap adjusting member 120 which is received by aligned apertures 121,122 in the arms of bracket 114. Fiberwasher 123 is disposed adjacent to head 124 of member 120 and is biased upward by compression spring 125 which rests against upper arm"1- 12 of bracket 114. Washer 123 and 130. Compression spring 131, interposed between the lower arm of bracket 114 and seating portion 132 of member 130, biases element 120,130 upwardly. In

7 the upward position, portion 133 of member positioned at right anglesto portion 128 is in a plane with same until portion 133 is below the lower ends of extensions'134136. I The elements of instantaneous trip device 100 herein-before described are assembled as a unit prior to insertion and securement to base 11. Securement is accomplished by a single screw 138 which passes through frame' aperture 139 and is received by a suitable threaded insert mounted tobase 11. After the subassembly is mounted to base 11 current carrying loop 18 is secured in place and thereafter magnetic armature 140 is mounted to frame 102.

Armature 140 comprises aplate-like member whose lower end is provided'with notch 141 for the passage of loop member 18. Notch 141 is defined by projections whose lower ends are narrowed at 142, 143 and are received by

frame slots

144, 145, respectively, in the web of frame member 102. The cooperation of projection portions 142,143 and slots l'44,l45 provides a pivotal connection between armature 140 and frame 102. Tension spring 146 is secured between armature ear 147 and frame ear 148 with these cars being operatively positioned so that the upper end of armature 140 is biased away from pole faces of pole piece 101 and the lowerend of 140 is firmly seated against the web of frame 102. I I

The upper end of armature 140 includes extension 151 which carries adjusting screw/152 engageable with 7 car 153 of common trip bar 155. As is well known to the art, rotation of common trip bar 155 by the armature of the instantaneous trip device is effective to bring about automatic tripping of the circuit breaker contact mechanism 30 inthat'clockwise rotation of common trip bar 155 with respect to FIG. 1 trips main I latch 107 mounted to trip bar 155 thereby releasing operating'mechanism cradle 31 to automatically open circuit breaker 10 using the energy stored in springs 34.

I of the V-shaped air gap between armature 140 and the faces of pole piece 101 to change, thereby changing the pull-in current required for attraction of armature 140 to pole piece 101 for tripping of circuit breaker 10. I

As previously noted, adjusting or calibrating element 120,130 is biased upward by coil spring 131 and is depressible by engagement with head 124 that is engageable from outside of housing cover 12 through hole 126 therein. When

element

120, 130 of the outer pole at the right of FIG. 2 is rotated to its PUSH TO TRIP position (see FIG. 3) depressing this element 120,130 causes one side of spring seating portion 132 to engage Test trip operation may also be accomplished by ma-,

nipulating a member that will release latch 107 by moving armature toward yoke 101. Although there have been described preferred embodiments of this novel invention, many variations and modifications will now be apparent'to those skilled in the art. Therefore, this invention is to be limited, not by the specific disclosure herein, but only by the appended claims.

The embodiments of the invention in which an exclusive privilege or property is claimed are defined as follows:

1. A multipole circuit breaker including cooperating contacts for each pole thereof; releasable contact operating means for opening and closing said cooperating contacts; latch means for maintaining said operating means in alatched position; a common trip bar extending between all poles of said circuit breaker, individual fault current responsive means for each pole of said circuit breaker any one of'which is operable, upon sensing a predetermined fault current condition, to act through said trip bar to release said latch means thereby releasing said operating means and opening said cooperating contacts; adjusting means for calibrating said fault current'responsive means; housing means wherein'the elements previously recited are disposed; said adjusting means'including a portion accessible for pivotal operation from outside of said housing tocalibrate said fault current responsive means; said portion when in a predetermined angular positionbeing selectively operable to release said latch means.

2. A multipole circuit breaker as set forth in claim 1 in which the portion is part of an element that moves said trip bar to release said trip bar upon selective operation of said portion.

3. A multipole circuit breaker as set forth in claim 2 in which the element is pivoted to calibrate the fault current responsive means; said element also being depre ssible; said portion upon selective operation thereof causing said element to be depressed; said portion being constructed with a common member accessible from outside of said housing being operable to both pivot and depress said element. I

4. A multipolecircuit breaker as set forth in claim 3 inwhich the fault current responsive means includes a magnetic instantaneous trip means comprising a stationary yoke and amovable armature normally spaced with a gap between said yoke and said armature; said portion upon operation thereof to calibrate said fault current responsive means causing said element to pivot and thereby adjust spacing between the armature and the yoke. I

5. A multipole circuit breaker as set forth in claim 1 in which the adjusting means includes an individually adjustable element for each of the fault current responsive means and said portion is part of only a first of, the

I adjustable elements.

6. A multipole circuit breaker as set forth in claim 5 in which the portion upon selective operation thereof causes said first element to move said trip bar to releas said trip bar.

transverse projection 200 of common trip bar 155. This pivots the latter clockwise with respect to FIG. 1 to release latch 107 thereby causing operating mechanism 30 to separate the cooperating contacts 25, 26of all poles.

7. A multipole circuit breaker as set forth in claim 6 in which each of the elements is pivoted to calibrate its said fault current responsive means; said first element also being depressible; said portion upon selective operation' thereof causing said first element to be depressed.

portion upon operation thereof to calibrate said fault current responsive means causing said element to pivot and thereby move said armature to adjust spacing between the armature and the yoke.

Claims

1. A multipole circuit breaker including cooperating contacts for each pole thereof; releasable contact operating means for opening and closing said cooperating contacts; latch means for maintaining said operating means in a latched position; a common trip bar extending between all poles of said circuit breaker, individual fault current responsivE means for each pole of said circuit breaker any one of which is operable, upon sensing a predetermined fault current condition, to act through said trip bar to release said latch means thereby releasing said operating means and opening said cooperating contacts; adjusting means for calibrating said fault current responsive means; housing means wherein the elements previously recited are disposed; said adjusting means including a portion accessible for pivotal operation from outside of said housing to calibrate said fault current responsive means; said portion when in a predetermined angular position being selectively operable to release said latch means.

3. A multipole circuit breaker as set forth in claim 2 in which the element is pivoted to calibrate the fault current responsive means; said element also being depressible; said portion upon selective operation thereof causing said element to be depressed; said portion being constructed with a common member accessible from outside of said housing being operable to both pivot and depress said element.

4. A multipole circuit breaker as set forth in claim 3 in which the fault current responsive means includes a magnetic instantaneous trip means comprising a stationary yoke and a movable armature normally spaced with a gap between said yoke and said armature; said portion upon operation thereof to calibrate said fault current responsive means causing said element to pivot and thereby adjust spacing between the armature and the yoke.

5. A multipole circuit breaker as set forth in claim 1 in which the adjusting means includes an individually adjustable element for each of the fault current responsive means and said portion is part of only a first of the adjustable elements.

6. A multipole circuit breaker as set forth in claim 5 in which the portion upon selective operation thereof causes said first element to move said trip bar to release said trip bar.

7. A multipole circuit breaker as set forth in claim 6 in which each of the elements is pivoted to calibrate its said fault current responsive means; said first element also being depressible; said portion upon selective operation thereof causing said first element to be depressed.

8. A multipole circut breaker as set forth in claim 7 in which the fault current responsive means includes a magnetic instantaneous trip means comprising a stationary yoke and a movable armature normally spaced with a gap between said yoke and said armature; said portion upon operation thereof to calibrate said fault current responsive means causing said element to pivot and thereby move said armature to adjust spacing between the armature and the yoke.