US849684A - Electric switch. - Google Patents

Description

No. 849,684. PATENTED APR. 9, 1907.

E. M. HEWLETT. ELECTRIC SWITCH.

APPLICATION FILED HAY 1. 1901.

UNITED STATES PATENT OFFICE,

EDWARD M. HEWLETT, OF SCHENECTADY, NEW YORK, ASSIGNOR TO GENERAL ELECTRIC COMPANY, A CORPORATION OF NEW YORK.

ELECTRIC SWITCH.

Specification of Letters Patent.

' Patented April 9,1907.

Application filed May 1,1901. Serial No. 53.242.

1o @ZZ whom, t may concer/t.'

Be it known that I, EDWARD M. HEWLETT, A citizen of the United States, residing at' lychene'ctady, county of Schenectady, State lf New York, have invented certain new and lseful Improvements in Electric Switches, if which the following is a specification.

This inventionrelates to the switches for- ;utting into circuit electric translating devices of variable current-consuming capacit-y.

The inventionis of particular value in connection with electric motors Where the starting current is so heavy that a fuse of large current-carrying capacity must be einpioyed and which for that reason does not cut out the 'motor on suchoverloads as if they continue for a considerable period of time would damage the armature. A motorarmature will safely withstand a heavy starting-current by reason of the rapidityT by which its counter electromotlve force 1s developed; but if a fuse suiiicient to with-l stand the starting-current be inserted in circuit with the motor it will permit the motor to carry suiiiciently heavy current to dalnage'the winding.

It is thc object of my invention to provide a simple switch which will guard against damage to the armature and which will quickly blow the fuse'and open the motorcircuit in case of overload.

I carry out 'the invention by providing the starting-switch with the two contacts connected" in circuit se-rvioti'm, one of which is connected with ause of relatively smaller current-carrying capacity to interrupt the motor-circuit at a predetermined overload. The two fuses arc connected in parallel relation with one leg of the circuit, the one whichis closed `iirst being opened when the switch is fully closed. y A

The novel features of' this invention will be more particularly hereinafter described and will be definitely indicated in the claims appended to .this specification.v

In the accompanying drawings, which illustrate the invention1 Figure 1 is a side elevation of a switch embodying my improvements. Fig. Z is a front view of the contacts, and Fig. 3 is a diagram showing the circuit relations.

1 represents an ordinary knife blade switch pivoted on a standard or lug 2, formed integrally with or electrically connected with one circuit-terminal, and 3 and 4 represent4 terminals in arallel-relation with a lead of the circuit. tlectrical'ly connected with these terminals are conductingclips 5 6, so arranged that the switch in closing first passes between the jaws of the clip 5 and completes thecircuit through a fuse 3'i of relatively great current-carrying capacity and subse uently open's at this point when the bla e 1 coines'in contact with 'the'clip 6, connected with a fuse of smaller current-carrying capacity.

7 represents an electricunotor or other translating device of a wide range of current-carrying capacity 4at different-periods of its starting operation. Thus in closing the circuit the translating device is first cut in through a heavy fuse untilthe translating device is put in action, after which alighter fuse is cut in and the-heavier one cut out. The circuit connections will be readily understood frompan'inspectionof Fig. 3, where current enters theI switch' through the fixed terminal 2, and while closing the latter is first connected through the fuse 3a and later through the fuse 4, the former being cut out when the4 latter is cut in, thus leaving the lighter fuse incircuit when the trans lating device is in its normal condition and permitting a prompt lopening of the circuit' Having thus'described my invention, what I claim as new, and desire to secure by'Letters Patent, is-

1. In combination with an electric motor, two automatic cut-outs of different cur-v rent-carrying capacity and means for cutting said cut-.outs into circuit with the motor consecutively and compellingthe cut-out of lesser current-carrying capacity tobe cut in later than the other. l

.2. The combination of an electric motor, with a switchhaving a single open position, two .thermal outputs of ldifferent currentcarrying capacity, 'and means for compelling the transfer of the current from that of greater currentcarrying capacity to that of lesser each time the circuit through said inotor is' closed.

In Witness whereof I have hereunto set my hand this 29th day of April,1901.

EDWARD M..IIEW'LETT. Witnesses:

BENJAMIN B. HULL, CHARLES STEINEB.

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