US783315A - Electrical protector. - Google Patents

Description

No. 783,315. PATENTED FEB. 21. 1905.

C. A. ROLFE,

ELECTRICAL PROTECTOR.

APPLICATION FILED APE.21, 1900.

LEiEi lIIVE LIL- :2 EHARIEiA.EU1FE UNITED STATEs Patented February 21, 1905.,

PATENT Orrlcri...

CHARLES A. ROLFE, OF CHICAGO, ILLINOIS, ASSIGNOR. BY MESNE ASSIGN- MENTS, TO ROLFE ELECTRIC CO.,

PORATION OF NEIV YORK.

OF ROCHESTER, NEW YORK, A COR- ELECTRICAL PROTECTOR,

SPECIFICATION forming part of Letters Patent No. 783,315, dated February 21, 1905.

Application filed April 21, 1900. $erial No. 13,705.

To all whom it may concern:

Be it known that I, CHARLES A. Home, a citizen of the United States, residing at Chicage, in the county of Cook and State of Illinois, have invented a certain new and useful Improvement in Electrical Protectors, of which the following is a full, clear, concise, and exact description, reference being had to the accompanying drawings, forming a part of this specification.

My invention relates to devices for protecting electrical circuits and instruments from the injurious effects of excessive or unduly strong currents.

Prominent objects of the invention are to provide an instrument of this kind especially adapted for use upon circuits where the current is normally large, to secure the same degree of accuracy and reliability in such instruments as is commonly secured in instruments operating upon circuits where the currents are normally exceedingly small, and to secure these results in a simple, expeditious, and economic manner.

To the attainment of these and other desired ends my invention consists in matters hereinafter set forth.

In the accompanying drawings, Figure is a protector embodying my invention. Figs. 2 and 3 are transverse sections of the same on line a b in Fig. 1, Fig. 2 showing the protector in its normal condition, and Fig. 3 showing the same in an operated condition.

In the protector illustrated in the drawings 1 have shown a base A, composed of insulating material-such as slate, porcelain, or the like provided with four binding-posts 1 1 and 2 2. The binding-posts 1 1 have attached to them conductors 3 3, which are understood to be the line conductors, while the binding-posts 2 2 have attached to them conductors a 4,which are understood to be the conductors running to the instrument to be protected. I have shown the two sides, of the circuit arranged in accordance with my invention. Of course, if desired, but one of such circuit-breaking devices could be employed.

In accordance with my invention I provide a low-resistance shunt 5 and a high-resistance shunt 6, and I associate with the latter a de vice adapted to open or break the circuit and capable of operating upon a rise in the current normally passing through the shunt. In this way it will be seen that a circuit carrying a heavy current can be opened or broken by such a sensitive and accurate device as can be operated only upon and by low tension and exceedingly small currents. This allows an accuracy and reliability of operation which cannot be secured by breaking the circuit by a device capable of carrying the normally large current and operating upon an access in the current.

As a preferred arrangement I employ as the sensitive and low-tension excess-operated device a form of current-breaking device illustrated, described, and claimed in my application for United States Letters Patent, Serial No. 618,795, filed January 11, 1897. This device consists of a couple of metallic rods 7 7, adapted to fit in sockets S 8 in the base A, a block 9, secured to the upper ends of the rods 7 7, a slide 10, arranged to slide upon the lower ends of said rods, springs 11 11, arranged to fit over the rods 7 7 and tending to separate the block 9 and slide 10, and a fusible button 12 associated with the block 9 and provided witha hook 13, which is connected by link 1% with the slide 10. The fusible button 12 contains a coil of line wire, which is included in the high-resistance shunt 6. By this arrangement the fusible button 12 holds the slide 10 normally in such condition that the springs 11 11 are under tension. \Vhcn, however, an excess current passes through the shunt 6, the button 12 is fused or melted or softened, thereby allowing the springs 11 to separate the block 9 and slide 10, and so cause the circuit-breaking device as a whole to rise and break the circuit.

As a convenient arrangen'ient the lowresistance shunt 5 is connected with the terminals 15 15, to which the upper ends of the rods 7 7 are secured. In this way it is obvious that the shunt-circuits are properly formed, so as to allow only a small portion of the current to pass through the coil contained in the'fusible button 12, while at the same time the circuit-breaking device is operated by this small portion of the current.

It is understood, of course, that the sockets 8 8 are connected with the terminals 1 1 and 2 2, as by conductors 16 16.

The relative resistances of the shunts 5 and 6 can be so proportioned as to cause any desired portion of the current to pass through the low-resistance shunts. As a result this simple and desirable form of circuit-breaking device, which can be advantageously operated only by very small currents, can be employed in connection with heavy and powerful currents.

\Vhat I claim as my invention is- 1. In an electrical protector, the combination with a pair of terminals, of a plurality of shunts all connected with said terminals, whereby all of said shunts form a part of a single circuit, and means controlled by one of said shunts for controlling said circuit, substantially as set forth.

2. In a protector for electric circuits, the con'ibination of a couple of shunts, a circuitbreaking device controlled by one of said shunts, and means for removing both shunts "from the circuit upon the operation of the circuit-breaking device, substantially as set forth.

3. In a protector for electric circuits, the combination with a couple of shunts, of a circuit-breaking device carrying both of said shunts and controlled by one of the same, whereby when the circuit-breaking device operates, both shunts are removed by it from circuit, substantially as described.

at. In a protector for electric circuits, the combination of a circuit breaking device adapted to operate so as to spring bodily out of its cooperating contacts, and a couple of shunts carried by said circuit-breaking device and controlled by one of the same, whereby when the device operates, both shunts are removed bodily from circuit, substantially as described.

5. In a protector for electric circuits, the combination of a pair of separate metal rods; a block securing the upper ends of the rods together; sockets into which the rods can fit; a slide arranged upon the ends of the rods, which lit into the sockets; springs arranged to separate the slide and the block; a fusible or so'ftenable button connected with the slide; a coil of line wire associated with the button and connected to the ends of the metallic rods; and a low-resistance shunt arranged around the coil of fine wire, substantially as described.

6. In a protector for electric circuits, the combination of a circuit breaking device adapted for bodily movement so as to spring out of its cooperating contacts, high andv low resistance shunts mounted upon said circuitbreaking device, and an excess-cturent-operated device included in the high-resistance shunt and adapted to operate to actuate the circuit breaking device upon the passage 'therein of an unduly strong current, substantially as described.

7. In an electrical protector, the combination with a pair of terminals, of a plurality of shunts all connected with said terminals, whereby all of said shunts form part of a single circuit, and means controlled by one of said shunts for opening the circuit, substantially as set forth.

8. In an electric-circuit protector, the combination with a pair of terminals, of a plurality of shunts connected with said terminals, whereby all of said shunts form part of a single circuit, one of said shunts having a relatively high resistance, and means controlled by said high-resistance shunt for controlling said circuit, substantially as described.

9. In an electric-circuit protector, the combination with a pair of terminals, of a plurality of shunts connected with said terminals, whereby all of said shunts form part of a single circuit, one of said shunts having a relatively high resistance, and means controlled by said high-resistance shunt for opening said circuit, substantially as described.

10. In an electriccircuit protector, the combination with a pair of terminals, of a pair of shunts both connected with said tern'iinals, whereby both of the shunts are connected in parallel with the circuit attached to the ter minals, and a thermal eXcess-current-operated device connected in one of said shunts, whereby such shunt becomes a high-resistance shunt relatively to the other one, said device being adapted to control the circuit upon the pars sagetherein of an unduly strong current, substantiall y as described.

11. The combination with a plurality of shunts, of a circuit-bro; king device adapted to bodily remove said shunts from circuit, and means, subject to one of said shunts, for actuating said circuit-lneaking device, substantially as described.

12. In an electric-circuit protector, thecombination with a pair of terminals, of a pair of shunts both connected with said terminals, whereby both of the shunts are connected in parallel with the circuit attached to the terminals, and a thermal excess-curreilt-operated device connected in one of said shunts, whereby such shunt becomes a high-resistance shunt relatively to the other one, said device being adapted to open the circuit upon the passage therein of an unduly strong current, substantially as described.

In witness whereof .I hereunto subscribe my name this 16th day of April, A. I). 1900.

CHARLES A. RULFIC.

\Vitnesses:

A. I\IILL1GR l-llcnrncto, CHAS. I IIUmnrr.

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