US1175358A - Starting apparatus for electric motors. - Google Patents

Description

. I ATTORNEY H. 0. JAMES. STARTING APPARATUS FOR ELECTRIC MOT-0R5. APPLICATEION FILED FEB. 2!, 1911.

1,175,358. Patented Mar. 14,191

WITNESSES: VENTOR UNITED STATES. PATENT onnicE.

HENRY D. JAMES, 015 PITTSBURGH, PENNSYLVANIA, ASSIGNOR TO WEST'QLNGHDUSE ELECTRIC AND MANUFACTURING COMPANY, A CORPORATION OF PENNSYLVANIA.

STARTING APPARATUS FOR ELECTRIC MOTORS Application filed February 21, 1911.

To all whom it may concern Be it known that I, HENRY D. JAMES, a citizenof the United States, and a resident of Pittsburgh, in the county of Allegheny and State. of Pennsyli'ania, have invented a new and useful Improvement in Starting Apparatus for Electric Motors, of which the following is a specification.

My invention relates to automatic devices for progressively short circuiting or cutting out resistance which is primarily included in the circuit of an electric motor, and it has for its object to provide a control apparatus in which a plurality of switches are connected to the respective sections of a resistor and are provided with means for regulating the short circuiting of the resistor sections, as the electromotive force of the motor builds up and the current cor respondingly decreases, which shall be operative without the employment of relays or interlocking connections.

The single figure of the accompanying drawing is a (liagram of a motor and control circuits constructed and combined in accordance with myinvention.

The energy for operating the motor 1 of the system shown is supplied from conductors 2 and 3, through fuses i and 5 and a manually operated switch 6. Normally connected in series with the armature 7 and series'field magnet winding 8 of the motor 1 is a resistor 9 comprising three sections 10, 11 and 12 which are successively and automatically short circuited by means of switches 13, 14 and 15, the stationary contact terminals 16, 17 and 18 of the several switches being connected to suitably spaced,

points in the resistor in order to cooperate with movable contact terminals 19, 20 and 21 in successively short clrcuiting the resistor sections at such points. The movable contact terminals 19, 20 and 21 are perinanently connected in serieswitheach other and to one 'terminal of the resistor 9 and also to one terminal of the shunt winding of the motor 1. Each of the stationary contact terminals is connected this operating coil 23 of the switch to w A belongs, to one terminal of the shunt field magnet Winding 22 and to one terminal of the armature 7 of the motor 1.

. The switches 13, 14 and 15 are severally Specification of Letters Patent.

Patented Mar. 14, 1916.

Serial No. 609,943.

provided with coils 24 that are wound to act in opposition to the operating coils 23 and are connected in series with each. other from the supply conducthr 3 to the terminals of the resistor and the shunt field magnet winding of the motor 1 which are connected together.

Each of the movable contact members 1E), 20 and 21 of the switches 13, 14 and 15 is connected to and operated by a core or armature 25 which is subjected to the magnetic field produced by'the corresponding coil 23. A core or armature 26 for the corresponding coil 24 is connected to the core or armature 25 and an adjustable armature or core 27 is also provided in order to adjust the force exerted by the coils 24 in opposition to that exerted by the closing coils 23.

The closing coils 23 are connected in multiple. circuit relation with dillerent proportions of the resistor 9 included in the circuit branches, consequently the potential at the terminals of the several coils is un-- equal and these coils may be uniform in construction and will tend to close the switches in a predetermined sequence. The actual'time at which each switch is closed and the time intervals between the closure of the switches may be varied as desired by adjusting the core members'fl'i which are influenced by the opposing coils 24 It is therefore evident that the sequential closure of the switches is primarily independentof the ad ustable cores and that the latter are provided for the purpose of adjusting; the

forces exerted by the opposing cells.

In the operation of the apparatus hereinbefore described,'when the switch 6 is closed to start the -motor- 1, the counter-electromotive force of the motor-will be a mini-' the core 26 by the coi'l 24, and thus closes the switch 13 to short circuit the resistor section 10.

As the counter-electromotive force of the motor 1 continues to build up,- the electromoti e force, to which the coil 23. of the switch 14 is subjected, increases until the switch 14 is closed, to short circuit the resistor section 11. As the counter-electromotire force of the motor 1 increases still further with its increasein speed, the increased electro-motive force upon the coil 23 and the diminished current in the coil 24 of the switch 15 will cause the said switch to close and short circuit the resistor section 12, thus ries therewith, a plurality of switches for excluding the resistance step by step, simi- -lar closing coils for the several switches connected across the motor circuit in multiple relation with one set of corresponding terminals connected to different points in said starting resistance whereby the switches tend to closesequentially, a core member on each switch influenced by its closing coil, a plurality of opposing coils for the several switches connected in series relation in the purpose of insuring sequen motor circuit and an independent adjustable core member for each switch influenced bythe opposing coil pertaining thereto.

2. A control system comprising an electric motor, a starting resistance adapted to be connected in series therewith, a lurality of switches for excluding the 'IESlStRIiCB step by step, closing coils for the several switches, connected across the motor circuit in multiple relation, a different proportion of said resistance being included in each branch whereby the switches tend to close sequentially, a plurality" of opposing coils for the switches connected in series relation in the motor circuit and an adjustable magnetizable core member influenced by each opposing coil. V v

3. A control system comprising an electric motor, a starting resistor in series therewith, a plurality of switches for excluding said resistor step by step, means for closing said switches in sequence in accordance with the counter electromotive force values of said motor, said 'means comprising a series 0 uniform coils connected across the motor circuit in multiple relation with one set of corresponding terminals connected at different points in. said starting resistor, means for opposing the closing of said switches in accordance with the current traversing said motor circuit, said means comprising a plurality of coils in series with said motor, and

adjustable means for varying the effect of said series coils.

In testimony whereof, I have hereunto subscribed my name this 31st day of Jan. 1911.

HENRY D. JAMES.

\Vitnesses I3. B. HINns, .T. V. Bnowx.

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