US1487694A - Circuit breaker - Google Patents

Description

M arch 18 1924..

"11,481, 94- C. P. BROCKWAY C IRCUIT BREAKER Original Filed April 2 Patented Mar. 18, 1924.

UNITED STATES PATENT OFFICE.

CARL P. BROOKWAY, OF TOLEDO, OHIO, ASSIGNOR TO INDUSTRIAL RESEARCH COR- PORATION, OF. TOLEDO, OHIO, A CORPORATION OF DELAWARE.

CIRCUIT BREAKER.

Continuation of application Serial No. 293,261, filed April 28, 1919. This application filed November 8, 1919. Serial No. 336,680.

To all whom it may concern.

Be it known that I, CARL P. BROCKWAY, a citizen of the United States, residing at Toledo, in the county of Lucas and State of 6 Ohio, have invented certain new and useful Improvements in Circuit Breakers, of which I declare the following to be a full, clear, and exact description.

This invention relates to improvements in 10 circuit breakers, and is a continuation of my co-pending application Serial Number 293,261, filed April 28, 1919, where the present invention is shown as applied in connection with the control switch of an electric l generating unit, driven by an internal combustion engine. It should be understood, however, that other applications of the invention are within the purview of this case. The principal object of the invention is the o provision of means for breaking an electric circuit whenever the current therethrough exceeds a predetermined rate of flow.

A subsidiary object of the invention'is the provision of an electromagnetic switch or circuit breaker, in which the armature constituting the movable element of the switch or circuit breaker, is normally held in operative position magnetically, and is magnetically short circuited when the current through the magnet coil exceeds a predetermined limit. 7

Another object of the invention is the provision of means for closing the switch armature and for holding out the short circuiting armature simultaneously. This is of advantage when starting a. generating unit of the kind referred to, for otherwise the heavy load upon the motor in the circuit at starting would draw suflicient current through the magnet coil to attract the short circuiting armature, which would cause the breaking of the motor circuit the moment that the starting lever was released by the operator.

Other objects, and objects relating to details of construction and economies of manufacture will appear as I proceed with the description of that embodiment of the invention, which, for the purposes of the present application, I have illustrated in the accomanying drawing, which is a diagrammatic illustration showing apparatus and connections embodying my invention.

In the drawing, at '21 is shown the core and at 22 and 23 the pole pieces of an electro-magnet. Just above the pole piece 23 is located a pin 24, upon which are separately pivoted an armature 25 of great magnetic permeability and an armature 26 of lesser permeability. Weights 27 and 28 tend to lift the forward end of the armatures 25 and 26 respectively. Upon the forward end of the armature 26 is a block 29 of insulation, which carries a pair of spring contacts 30 and 31, adapted to engage fixed contacts 32 and 33. Contact 31 is bent down so as to reach contact 33 before contact 30 reaches contact 32. Small blocks 9 of non-magnetic material are interposed between the pole piece 22 and armature 2 6 to prevent these parts from coming into engagement with each other.

Above the base of the spring contacts 30 and 31 is secured an upwardly extending spring finger 34, which at its upper end bears against the lower surface of the spring metal arm 35, fastened at its rear end by a screw 36 to the container for the apparatus. The

arm normally bears against the flat base of a cam 37, which is secured to a rock-shaft 38, and thereby tends to hold the rock-shaft together with its handle 39 in the position illustrated in the drawing. A stop arm 40 is secured to the armature 25 and extends forward and partially above a second cam 41, also secured to the rock-shaft. In the normal position of the rock-shaft, stop arm 40 is not engaged by cam 41, but when the handle 39 is drawn to either of its extreme positions, indicated by the dotted lines B and C in the drawing, one of the points of the cam contacts with the under surface of the stop arm 40, and thereby holds the armature 25 in the elevated position shown in the drawing. However, when the handle 39 is in the neutral position, marked A, this armature may be depressed manually by pressure applied to the top of a push pin or button 42.

43 and 44 are line wires. A conductor 45 connects line wire 43 with a coil 46 wound around the core 21, the opposite end of the coil bein connected by a flexible conductor 47 with t e contacts 30 and 31. Conductors 48 and 49 provide electric paths back to line wire 44 from the fixed contacts 32 and 33 respectively. Within these latter conductors may be located the translating devices, for

the protection of which the circuit. breaker of the present. invention has been devised. Merely for purposes of illustration, I have shown herein, an electric motor 50, with a tield winding 51. So as the present invention is concerned, it is not essential that there be two conductors L8 and l9, as one such conductor would be s itticient to illustrate the invention. The separate contact 33 and the separate conductor are employed in practicd to obtain a current through the motor iield prior to the flow of current through the motor armattn'c. tor a purpose that will be well .ncerstood by tho' skilled. in the art. It is for this reason tl spr'. finger 31 is bent down to malte connection with contact 23 before any connection made between conta-ts 30 and In operation, the t1 1 ml the harcle 39 to 1oz oi? the I ts and 31. therecur iroin e l3 through contact El, ilfiitl ticld winding 5i also through contacts SO and wire 44% and armor 50 to line wire all the some time one or the other of the points of cam il. shift d by the rock-shaft 38 into the path of move ment of stop arm 40, thereby preventing the descent of armature untn the operator lets go of the handle 39, which then automatically returns to neutral position be ca .se of the action of the spring arm 3 upon the lower surface of cam 3' Thus, a heavy surge of current through coil 6 has no effect while the apparatus bei started by the operator. However, shout this heavy surge of current continue for any reason after the operator has released the handle 39, or should a current ot more than predetermined strength occur at any time later in the operation of the system, then such a current acting; through coil 46 would generate magnetic li. es of force at suiiicient density to over-saturate armature 26, and attract armature 25, which is of greater permeability than armature 26. and which, moreover, may move directly into contact with pole piece '22 instead of being separate; therefrom by non-magnetic material as is the case with armature 26. As soon as the armature 25 touches pole piece 22 it magnetically short circuits armature 26, which then swings upon the pin as a pivot, because of the influence of weight 28. In this way the electric circuit is brolzen. It may also be broken at. any time at the will of the operator by simply pressingdown upon the push pin or button 42. V

I am aware that. the particular embodiment of my invention above described, and illustrated in the accompanying drawing, is susceptible of considerable variation without departing from the spirit thereof, and

contact bacl-I to line wire and tlnzretorc l desire to claim my invention broadly as well as specilicill as indicated by the appended claims.

I claim as my invention:

1. in an automatic circuit breaker tor electric circuits, the combination of an electro-n-ignet, an armatu e control -l by the clectro-in, adapted to magne L --c when the cm: magnet. exceeds a preileteruu.- cd nut, and conunon means tor chasing said arnnu ture and holding open said set-out, armature.

In an electric switch, an lici,il'=i'llllg a coil and a pole piece, a pair of in position tc attracted l y raid one of said i tures carrying contact. d contact adapted ed a'tu' e contact when 'nznurc is shi ted to\ 1rd the pole nanual means tor shit said last irn'iature to bring said contacts toanti at the same time tor holding other armature out o t attracted position, and. means tending to withdraw said e electroa run: n re l pore ne in electric a by said a contact arryin r armature, whereby, when said man ial means released, magnetism innuced by a current of more than a certain predct rt w th, wi l over-satui. carrying armature. causing armature, and permitting it to be withdrawn.

3. In an electric switch. an electro-nu1g net ha ing: a coil and a pole piece, an armature o great permeability, and an armature of permeability. both in position to be attracted by said pole piece. said armature of le. er permeability carrying an electric contact. a fixed contact adapted to be enga cd by the contact oi": said armature er permeability when the latter is shifted toward the pole piece. manual means for shifting the armature of lesser perme ability to bring said contacts together, and at the same time tor holding said armature of greater permeability out of attracted position, and means tending to withdraw said armature of lesser permeability, whereby, when said manual means is released, a current in said circuit 0'? more than a certain predetermined strength will cause said armature of lesser perineabilty to become oversaturated, thus causing said armature of greater permeability to be drawn into encagcment with said pole piece. thereby magnetically short circuiting: the armature of lesser permeability and permitting it to be withdrawn.

1-. In an electric switch. an electro-magnet having a coil and a pole piece, an armature of greater permeability and an armsture of lesser permeability, both in position to be attracted by said pole piece, said armature of lesser permeability carrying an electric contact, and said armature of greater permeability carrying a stop arm, a rock-shaft capable of limited motion from a neutral position, a cam thereon adapted to shift said armature of lesser permeability toward said pole piece when said shaft is rocked to its operative position, a second cam on said shaft adapted to engage said stop arm at the same time to hold said armature of greater permeability away from the pole piece, means tending to withdraw said armature of lesser permeability, whereby, when said rock-shaft is in neutral position a current through said coil of more than a certain predetermined strength will cause said armature of lesser permeability to become over-saturated, after which said armature of greater permeability will be drawn into engagement with said pole piece, thereby ma netically short circuiting said armature o' lesser permeability and permitting it to be withdrawn, and whereby when said rock-shaft is in neutral position and a current of less than said predetermined strength is flowing, said stop arm may be manually depressed to shift said armature of greater permeability into engagement with said pole piece, thereby magnetically short circuiting said armature of lesser permeability and permitting it to be withdrawn.

5. In an automatic circuit breaker for an electric circuit, the combination of an electro magnet having an armature, means for breaking the electric circuit by the movement of said armature, a second armature for said electromagnet adapted to magnetically short circuit the first armature when the current in the circuit exceeds a predetermined value, and means operable to prevent said second armature from acting when it is desired to send a high current through said circuit.

6. In an automatic circuit breaker, for an. electric circuit, the combination of an electromagnet having an armature, means for breaking the electric circuit by the movement of said armature, a second armature for said electromagnet adapted to magnetically short circuit the first armature when the current in the circuit exceeds a predetermined value, and means to automatically prevent said second armature from acting when said electric circuit is first closed.

7. In an automatic circuit breaker for an electric circuit, the combination of an electromagnet having an armature, means for breaking the electric circuit by the movement of said armature, a second armature for said electromagnet adapted to magnetically short circuit the first armature when the current in the circuit exceeds a predetermined value, and manual means to close said electric circuit and at the same time prevent said second armature from acting.

8. In an automatic circuit breaker for an electric circuit, the combination of an electromagnet having an armature, means for breaking the electric circuit by the movement of said armature, a second armature for said electromagnet adapted to magnetically short circuit the first armature when the current in the circuit exceeds a predetermined value, and manual means to close said electric circuit and at the same time prevent said second armature from acting, and manual means to cause said second armature to act.

In testimony whereof, I afiix my si ature.

CARL P. BROCK AY.

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