US863185A

US863185A - Protective device for electric circuits.

Info

Publication number: US863185A
Application number: US23381204A
Authority: US
Inventors: Thomas I Jeffries
Original assignee: Stanley Electric Manufacturing Co
Current assignee: Stanley Electric Manufacturing Co
Priority date: 1904-11-22
Filing date: 1904-11-22
Publication date: 1907-08-13
Anticipated expiration: 1924-08-13

Description

PATENTED AUG. 18, 1907.

T. I. JEFPRIES. PROTECTIVE DEVICE FOR ELECTRIC CI RCUITS.

APPLICATION FILED NOV. 22. 1904.

IINEHTOTI hzmm's [Jeff/"I53. by m ax I THOMAS I. JEFFRIES,

OF PITTSFIELD, MASSACHUSETTS, ASSIGNOR TO STANLEY ELECTRIC MANUFACTURING COMPANY, OF PITTSFIELD, MASSACHUSETTS, A CORPORATION OF NEW- JERSEY;

Specification of Letters Patent.

PROTECTIVE DEVICE FOR ELECTRIC CIRCUITS.

Patented Aug. 13, 1907.

Application filed November 22,1904:- Serial No. 233.812.

To all whom it may concern:

Be it known that 1,.TlIOMAS I. .Inrrmns, acitizen of the United States, residing at Pittsfield, in the county of Berkshire and State of Massachusetts, have invented certain new and useful Improvements in Protective Devices for Electric Circuits, of which the following is a specification.

My invention relates tection of electric circuits.

It is ordinarily necessary; to protect electric circuits against the flow of too great an amount of current there in, and iorthis purpose a magnet coil is ordinarily provided arranged to open a switch in the circuit whenever the current reaches a dangerous amount. On some circuits on which a temporary overload is likely Y to occur at frequent intervals, it is inconvenient ii the circuit-breaker operates for each of these overloads. It

has been customary, heretofore, in such cases to pro vide what is known as a time-limit circuit-breaker with v j proposed heretoiore to supplement the time-limit tripa movable member, controlled by the trip-coil, provided with retarding means, so that an overload of a certain duration is required to effect the operation of the circuit-breaker. Such time-limit devices are, however, sometimes a source of danger, since, ii a very heavy over-load occurs, it is desirable that the circuit should be opened immediately.. It has consequently been ping-coil or relay with a second coil, without retarding devices, so proportioned as to operate only on excessive over-loads. r

My invention consists in arranging a single coil so that it controls two movable members, one arranged with a time-limit device, and the other without. Thus, a single coil takes the'place of the two coils which have been sometimes employe'd heretofore.

More specifically considered, my invention consists in the combination with a single coil of two magnetic members arranged in; series in the magnetic circuit of the coil, one of the members provided with retarding means, and the other member without retarding means but arranged to respond only to a much heavier current in the magnet coil than is required to produce a move ment of the first member.

My invention will best be understood by reference to the accompanying drawings, in which Figure 1 shows a magnetically-operated relay arranged in accordance with my invention, and Fig. 2

I shows a diagram of the circuit connections.

In Fig. 1, A represents the magnet coil, which is provided with a magnetic casing B partially surrounding the coil. O represcnts a movable core which is shown as of the ordinary type, and which is connected at its lower end to a dash-pot D. The core O carries the into magnetic-relays for the prois normally held in the position shown by gravity or by a spring. When a predetermined current-flowpasses through the coil A, the core 0 starts to move upwards,

but this motion is retarded by the dash-pot D, so that the contact member E does not engage the stationary contacts e e, until a predetermined time has elapsed.

' lithe overload has meanwhile ceased, the core C drops back to the position shown, without bringing the member E into engagement with 'the stationary contacts. F represents a second movable magnetic member which is included, in series with the core 0 and the casing B, in the magnetic circuit of the coil A. The member F is normally held against the stops ff, as shown, by the tension-spring G, and this spring is so proportioned that the magnetic pull upon the member F is not strong enough to move it downward away from its stops, unless the coil A is traversed by a current corresponding to a heavy overload in the circuit to be protected. The member F will consequently remain stationary on an ordinary overload, which cause the core C to start on its-upward movement; but in case a very heavy overload occurs, the member F will be instantly drawn down, bringing the insulated contact member H into engagement with the stationary contacts h h.

The contacts 0 e and h h are connected in parallel in the control circuit, as is shown in Fig. 2. From Fig. 2 it will be seen that it either contacts e e-or contacts h h are electrically connected, bytheir respective contact members E or H, a circuit will be closed through the battery I, and trip-coil J on the circuit-breaker K, which is connected in the same circuit with the magnet coil A. The operation of either movable member C or F, as has been described above, will thus result in opening the circuit to be protected.

I do not desire to limit myself to the particular construction and arrangement of parts here shown, but

aim in the appended claims to cover all modifications which are within the scope ofmy invention.

What I claim as new and desire to secure by Letters Patent of the United States, is,

1 In combination with a circuit to be protected, a magnet winding energized from said circuit, two independently-movable members controlled by said winding and responsive to different overload current strengths therein, means for retarding the movement of the member responding to the'smaller current flow, a switch in said circuit, and connections between both of said members and said switch operative upon the effective overload movement of either of said members to open said switch.

2. In combination with a circuit to be protected, a magnet winding energized from said circuit, two independently-movable members controlled by said winding and responsive to different. current strengths therein, means for retarding the movement of the member responding to the smaller current-flow, relay contacts carried by said members, a switch in'said circuit to be protected, and a trip magnet for said switch in circuit with the relay contacts, carried by both of said members.

3. In combination with a circuit to be protected,. a magnet winding energized from said circuit, two independe'ntly-movable magnetic members included in series in the magnetic circuit of said winding and responsive to difierent current strengths therein, means for retarding the movement of the member responding to the smaller current flow, relay contacts carried by said members, a switch in said circuit to be protected, and a trip-magnet for said switch in circuit with the relay contacts carried by both of said members. I

4. In combination with a circuit to be protected, a' magnet winding energized from said 'circuit, two independ ently movable members controlled by said winding and responsive to different current strengths therein, a switch in said circuit to be protected, means controlled by the movable member responsive to the small current flow in said magnet winding. for opening said switch after a definite time interval, and means controlled by the movable member responsive to the greater current flow for opening said switch instantaneously.

In witnesswhereof, I have hereunto set my hand this first day of November, 1904.

' THOMAS l. .TEFFRIES. Witnesses SAMUEL E. WInmrInLn, JAMES E. FLYNN.