US2942079A

US2942079A - Circuit breaker

Info

Publication number: US2942079A
Application number: US737600A
Authority: US
Inventors: Hiller D Dorfman
Original assignee: Westinghouse Electric Corp
Current assignee: CBS Corp
Priority date: 1958-05-26
Filing date: 1958-05-26
Publication date: 1960-06-21
Anticipated expiration: 1977-06-21

Description

H. D. DORFMAN CIRCUIT BREAKER June 21, 1960 2 Sheets-Sheet 1 Filed May 26, 1958 INVENTOR Hiller D. Dorfmun WITNESSES ATTORNEY June 21, 1960 H. 0. DORFMAN CIRCUIT BREAKER Fig.

Fig.4.

United States Patent @fifice Patented June 21, 1960 CIRCUIT BREAKER Hiller D. Dorfman, Beaver, Pa., assignor to Westinghouse Electric Corporation, East Pittsburgh, Pa., a corporation of Pennsylvania Filed May 26, 1958, Ser. No. 737,600

8 Claims. (Cl. 200-106) of the circuit breaker without removing the breaker cover.

Another object of the invention is to provide a circuit breaker embodying an electromagnetic tripping means comprising a fixed magnet yoke and a movable armature with improved means for adjusting one element of said electromagnetic tripping means to vary the magnetic air gap to thereby vary the minimum overload current required to trip the breaker.

Another object of the invention is to provide a circuit breaker embodying a tripping electromagnet hawing a fixed magnet yoke and a movable armature with improved means occupying a minimum of space for adjusting the position of the armature relative to the fixed magnet yoke to vary the tripping characteristic of the tripping electromagnet.

The invention both as to structure and operation, together with additional objects and advantages thereof, will be best understood from the following detailed description thereof when read in conjunction with the accompanying drawings.

In said drawings:

Figure l is a vertical sectional view through a circuit breaker embodying the principles of the invention.

Fig. 2 is a top plan view of a portion of the circuit breaker with the cover broken away showing a portion of the adjusting means for one pole of the breaker.

Fig. 3 is an enlarged elevational view partly in section showing the adjusting means.

Fig. 4 is an enlarged elevational view of the adjusting cam.

The invention is illustrated as applied to a circuit breaker embodying an operating and contact mechanism of the type fully disclosed in Patent No. 2,419,125, issued Apr. 15, 1947, to Hiller D. Dorfman and Gerald J. Freese and assigned to the assignee of the present invention.

The circuit breaker is of the two or three-pole type and, since the contact and trip means for all poles are the same, only the center pole in which the operating mechanism is located will be described. The circuit breaker comprises generally a base 11 and a cover 13 both of molded insulating material, a stationary contact 15, a movable contact 17, an operating mechanism indicated generally at 19 and a trip device indicated generally at 21.

The stationary contact 15 is rigidly mounted on the inner end of a conducting strip 23 which has a terminal connection 25 at its outer end. The movable contact 17 is mounted on a movable switch arm 27 which is pivoted at 29. The operating mechanism 19 consists of a releasable member 31 pivoted at 33 and operatively connected to the switch arm 27 by a pair of toggle links 35 and 37. The knee of the toggle 3537 is connected by means of over-center operating springs 39 to a pivoted operating handle 41 which is movable between an on and an off position to effect movement of the switch arm 27 to the closed and open positions in a Well known manner.

When the circuit breaker is in the closed position, the toggle 35-37 is in an overset position and holds the switch arm 27 in the closed contact position. When the circuit breaker is in the closed position and the releasable member 31 is released, it causes collapse of the toggle 35-37 and movement of the switch arm to the open position. The mechanism is reset and relatched by movement of the operating handle 41 to the off position. Thereafter, the contacts are closed by movement of the handle 41 to the on position.

Only a brief description of the operating mechanism and its operation has been given. For a fuller understanding of the operating mechanism, reference may be had to the previously mentioned Patent No. 2,419,125.

The releasable member 31 is releasably held in its operative position by engagement of the free end thereotwith a latch 43 mounted on a pivoted trip bar 45 that is common to all of the poles of the breaker and which is operated by the trip device 21 of any pole of the breaker to elfect release of the releasable member 31.

The trip device 21 comprises an electromagnet indicated generally at'47 comprising a fixed angular magnet yoke 51 of magnetic material having a fixed core 53 rigidly secured thereto about which is Wound an energizing coil 55. The upper end of the fixed core 53 forms a pole piece 56. The lower end of the coil 55 is connected to a terminal 57 which is secured to the base 11 by a screw 59. A flexible conductor 61 is connected, at one end, to the terminal 57 and, at the other end, to the movable contact member 17. The upper end of the coil 55 is rigidly secured to the inner end of a conductor 63 at the outer end of which is mounted a terminal connector 65.

Mounted on the upwardly extending portion of the yoke 51 is a bracket 67 of non-magnetic material having an opening therein in which is pivotally supported an armature 69 which is provided with a projection 71. The projection 71 extends downwardly and has an insulating member 75 on the lower end thereof which, upon operation of the armature 69, engages a projection 77 on the trip bar 45 and actuates the latter to effect release of the releasable member 31. The armature 69 is biased to its unattracted position by springs 79 tensioned between the bracket 67 and a bracket 81 of magnetic material secured to the armature 69.

The electromagnet 47 is supported by means of projections 83 on opposite sides of the angular yoke 51 which extend through openings in spaced side plates 85 which form a frame. The side plates 85 are provided with projections 87 at their lower ends which extend through openings in the base 11 and are riveted over at 89 to rigidly secure the frame and the trip unit to the base.

Means is provided to selectively determine the minimum overload current required to trip the breaker. This is accomplished by adjusting the position of the armature by means of an adjusting device shown generally at 91. The adjusting device is supported by a plate 93 (Fig. 3) rigidly secured to the side plates 85. Mounted for rotation relative to the plate 93 is an adjusting knob 95 which extends through an opening in the cover 13. A spring Washer 97 biases a flange 99, Which is integral with the knob 95, against the inner surface of the cover 13. A reduced portion 101 of the knob 95 rotates in:

- an opening in the plate 93 and has a downwardlyexq;

3 tending shaft 103 at the lower end thereof. A cam 195 is mounted on the non-circular portion of shaft 103 (shown in Fig. 2) for rotation therewith and is held in ,placeby a springclip 1G7 seated in a groove 1l in the shaft. Apin or plungerof non-magnetic material 111 is disposed between the-cam 165 and a struckout portion 113 of the armature 69. A rounded head-115 of the pin 111 bears against the underside of the cam 105 and the lower end of the pin serves as a stop for the armature 69. As seen in Fig. 4, the under surface of the cam 1105 is stepped as indicated at117 so that, upon rotation of the cam,.thepin or stop 111 is moved up or down depending on the directionof rotation. This movement of the pin 111, through the portion 113 on the armature .69, varies the position of the armature relative to the pole piece 56 and the size of the air gap there'cetween.

The pin or stop 111 is guided by a sleeve 1-19 of nonmagnetic material which surrounds the pin and is rigidly mounted in an adjustable guide plate 121. The guide plate 121 also of non-magnetic material is pivotally supported at one end by trunnions 12 3 thereon which extend into bearing openings 125 in the side plates or frame 85. A screw 127 which threadedly engages the plate 121 at its end opposite the trunnions, has a reduced portion 129 which fits in a narrow slot 131 in the fixed plate 93 and a head 133 bearing against the upper surface of the plate 93. The slot 131 is of less width than the body or the screw 127, so that upon turning the screw 127, it is held against endwise movement and the guide plate .121 is moved up or down about its pivot 123 thereby .changing the angle of the pin 111 with respect to the portion 113'. It will be seen that this movement will also vary the point of engagement of the lower end of the pin 111 with the portion 113 there-by varying the moment arm of the pin relative to the pivot of the armature '69. This arrangement provides a. fine adjustment for the factory calibration of the device and this calibration may be fixed by solder 134 or other sealing material.

Further factory calibration may be eiiected by bending the portion 113 of the cracket 81 which is secured to the armature 69. This varies the position or" the armature 69 relative to the pin 111 and thereby varies the magnetic air gap.

. In calibrating the. trip device, the knob 95 (Figs. 2 and 3), is first rotated to the H? position after which the portion 113 is bent up or down to provide the correct air gap for the Hi setting. The knob 95 is then rotated tothe Lo position and the screw 127 is then rotated in the direction to give the correct air gap for the 1.0" setting.

The top of the knob 95 is provided with a pointer 135 (Fig.2) and the cover 13 is provided with index points 137, around the knob 95. The upper surface of the cam 105 is provided with notches 1.39 (Fig. 4-) which correspond to the index positions 137. The notches 139 are adapted to engage a projection 141 on the underside of the fixed plate 93 to prevent accidental movement of the knb'95 and the cam 1 35.

Adjustment of the armature 69 is eifected by inserting a screw driver in the slot in the knob 65 and pushing the knob down to disengage the notch 139 in the earn 105 from. the projection 1.41. The knob is then rotated to bring the pointer 135 to the desired index point. This rotates the cam 195 to bring the selected step 117 into engagement with the head 115 of the pin 111. When the knob and cam are in the selected position, the knob is released and the spring 97 restores the parts upwardly to engage the selected notch 139 with the projection 14 1.

While the invention has been disclosed in accordance with the provisions of the patent statutes, it is to be understood that various changes in the structural details and arrangement of parts thereof may be made without cleparting from the spirit of the invention.

I claim as my invention:

1. A circuit breaker comprising relatively movable contact means and means releasable to effect opening of said contact means, trip means including a trip member movable to a tripping position to effect release of said releasable means, electromagnet tripmeans having an armature movable to engage and move said trip member to said tripping position, a. settable member for varying the magnetic air gapof said electromagnetic means, an actuating memberdisposed between said settable member and a portion on said armature, said actuating member engaging saidportion on said armature and moved by said settable member to vary the position of said armature, and guide means to guide said actuating member for longitudinal movement.

2. A circuit breaker comprising relatively movable contact means and means releasable to efiect opening of said. contact means, trips means including a trip member movable to a tripping position to eftect release of said releasable means, electromagnet trip means having an armature movable to engage and move said trip memher to said tripping position, a settable cam member for varying the magnetic air gap of said electromagnetic means, an actuating plunger disposed between said settable cam member and a portion on said armature and moved by said settable cam member to vary the position of said armature, and adjustable guide means for said actuating plunger adjustable to vary the angular position of said actuating plunger relative to said portion onsaid armature.

3. A circuit breaker having relatively movable contact means and means releasable to effect opening of said contact means, a trip member movable to a tripping position to effect release of said releasable means, electromagnetic trip means including a fixed magnet yoke and an armature movable to engage and move said trip member to said tripping position, a slidable adjusting member having one end disposed in engagement with a portion on said armature, a manually settable cam member engaging the other end of said slidable member for actuating said slidable member, guide means for said slidable member, and means for adjusting the position of said guide means to thereby vary the position of said slidable member relative to said portion on said armature.

4. A circuit breaker having relatively, movable contact means and means releasable to effect opening of said con tact means, a trip member movable to a tripping position to effect release of said releasable means, electromagnetic trip means including a fixed magnet yoke and an armature movable to engage and move said trip member to said tripping position, a slidable adjusting memher having one side disposed in engagement with a portion on said armature, a manually settable cam member engaging the other end of said slidable member for actuating said slidable member, pivoted guide means for said slidable member, and means for adjusting the position of said guide means to thereby vary the angular position of said slidable member relative to said-portion .on said armature.

5. A circuit interrupting current responsive device comprising an energizing winding, a fixedmagnet yoke including a fixed core member disposed to -be energized by said winding, a pivoted armature movable toward and away from said fixed core member, a rotatable cam member, means for rotating said cam member, a slidable member disposed between said cam member and said armature and slidably movable by rotation of said cam member to vary the position of said armature relative to said fixed core member, guide means for guiding the sliding movement of said slidable member, and adjusting means adjustable to vary the position of said glide-means to thereby vary the angular position of said slidable member relative to said armature.

6. A circuit interrupting current responsive device comprising tin-energizing winding, electromagnetic means comprising a fixed core member disposed to be energized by said winding, a pivoted armature movable toward and away from said fixed core member, a frame supporting said electromagnetic means, adjusting means comprising a rotatable cam member supported on said frame independently of said electromagnetic means, a slidable member disposed between said cam member and said armature and slidably movable by rotation of said cam member to vary the position of said armature relative to said fixed core member, guide means pivotally mounted on said frame for guiding the sliding movement of said slidable member, and means for pivotally adjusting said guide means to thereby vary the angular position of said slidable member relative to said armature.

7. A circuit interrupting current responsive device comprising an energizing Winding, a fixed core member disposed to be energized by said winding, a movable armature movable relative to said fixed core member, adjusting means comprising a slidable member having one end engaging said armature, rotatable cam means engaging the other end of said slidable member, means for rotating said cam means to cause sliding movement of said slidable member to vary the position of said armature relative to said fixed core member, guide means for said slidable member, and means for adjusting said 6 guide means to vary the angular position of said slidable member relative to said armature.

8. A circuit interrupting current responsive device comprising an energizing Winding, a fixed core member disposed to be energized by said winding, a pivoted armature movable relative to said fixed core member, adjusting means comprising a slidable member having one end engaging said armature, rotatable cam means engaging the other end of said slidable member, means for rotating said cam means to cause sliding movement of said slidable member to vary the position of said armature relative to said fixed core member, pivoted guide means for said slidable member, and means for adjusting said guide means about its pivot to vary the angular position of said slidable member relative to the pivot of said armature.

References Cited in the file of this patent UNITED STATES PATENTS 2,135,490 Blodgett Nov. 8, 1938 2,691,707 Lovejoy Oct. 12, 1954 2,824,925 Grissinger et a1. Feb. 25, 1958 FOREIGN PATENTS 218,702 Great Britain July 7, 1924