US851811A - Automatic motor-starter. - Google Patents

Description

No. 851,811. PATENTED APR.'3 0, 1907.. G. D. KNIGHT.

AUTOMATIC MOTOR STARTER. APPLIOATIOH FILED MAY 25. 1900.

WHfness-es: 1 lnvenifor:

' Charles D. Knigh-lf UNITED STATES PATENT OFFICE.

CHARLES D. KNIGHT, F

SCHENECTADY, NEW YORK, ASSIGNOR TO GENERAL ELEoTRIoooMPANY, A CORPORATION OF NEW YQRK.

- AUTOMATIC MOTOR-STARTER.

To all whom it may concern.

well as the main operating and consequently 4o which is arranged Be it known that I, QHARLEs D. KNIGHT, a citizen of the United States, residing at Schenectady, in the county of Schenectady, State of New York, have invented certain new and useful Improvements in Automatic Motor-Starters, of which the following is a specification. I

My invention relates to the automatic con trol of devices from a distance, and particularly to automatic starting-switches tor electric motors.

Starting-switches have been arranged heretofore with magnet windings controlled from a distance for moving the switches from oif to running position to start the motor. Such switches have also been provided with means for cutting out the operating magnet when the switch is moved and connecting in circuit a smaller looking or retaining magnet for holding the switch in running position; the switch being arranged to return automatically to starting position when the retaining magnet is .de-energized. With such an arrangement the retaining magnet is continually energized, as long as the motor is running.

My invention consists in providing a mag-- netically operated switch wlth a latch which automatically engages and retains the switch in running. magnet may be de-energized when the switch is moved and the switch retained in running position without the expenditure of current or this purpose, and with a second magnet winding, which is arranged. to disengage the latch to stop the motor. This winding, as

winding, is in circuit only momentaril may be made of smal size. Furthermore, no current is em loyed while the motor is running, except t at in the motor itself, so that the efiiciency of the device is increased.

My invention will best be understood by reference to the accompanying drawing, which shows diagrammatically an automatic motor starter arranged in accordance with my invention. 7

In the drawing, A represents the armature, and a the field winding, of a shunt-wound motor controlled by the starting switch B,

when moved to out out resistances C from the armature circuit, and which is operated by the solenoid D.

position, so that the operating Specification of Letters Patent. I Application filed May 25, 1906. Serial No. 818,697.

I I l Eatented April 30,1907.

open automatically the circuit of magnet winding D.

F represents a second magnet winding adapted when energized to withdraw latch so as to allow switch-member B to fall to its lowest position.

f represents a switch which breaks the circuit of magnet winding F when switch-member is in its lowest nosition.

G represents a suitable retarding device, such as a dash-pot operatively connected to the switch-member 16 adapted to retard its upward movement, but to permit its free downward movement.

The magnets I) and IF are controlled by the switch Hat the distant point, which I have shown as controlled by a float I and a I tank J, supposed to be supplied by a pump (not shownl driven by motor A. W hen the water in the tank J falls below a certain levei, the downward movement of float I brings switch II into engagement with the contacts It, thereby closing a circuit from the lower linewire L through contacts 7t, through switch d and magnet winding I) to the upper line-wire I1. IVIa-gnet winding D consequently draws up switch-member B retarded by dash-pot G. The first movement of switch-member B to close, thereby closing the motor-circuit across the line-wires L. The further movement of switch-member B gradually cuts out the resistances C to bring the motor up to s eed. I hen all the resistances are cut out, tlie notch e is brought o posite the s ring latch E, which enters t e notch ho ding switch-member in running position. At the same time the circuit of solenoid D is broken by switch d.

When the pump driven by the motor A has raised the water-level in tank J to a certain height the switch-member J is brought into engagement with contacts 72., thereby closing allows switch-member F) Although I ave shown my invention cg plied to a shunt-wound motor, it is equal applicablej'to the control of any other type of motor for either direct or alternating current. When usedwith an alternating-current motor, my invention possesses a special advantage, in that the operating magnets are cut out of circuit except at the moment of starting, so that the losses due to eddy currents and hysteresis, which occur in alternating-current magnets, are almost wholly avoided. I do not desire to limit myself to the particular construction and arrangement of parts here shown, but aim in the a pended claims to cover all modifications. w ch are within the scope of my invention.

What ll claim as new anddesire to secure by Letters Patent of the United States, is:

I 1. in combination, a member to be moved, a magnet winding adapted to move said member, a latch adapted automatically to engage and to release said member when moved, means for automatically (ls-energizing said magnet winding when said member is moved, and a second magnet windin iida ted when energized to disengage said atc 2. In combination, a magnet winding adapted to move said member, aretarding device operativelv connected to said member, a latchadapted autoto retain said memmatically to engage and her when moved, means for automatically de-energizing said magnet winding when said member is moved, and a second magnet winding adapted when energized to disen gage said latch.

starting switch therefor arranged to return automatically to off position, a magnet winding adapted to move said switch to running position,

5 5 engage and to retain said switch in rimning a member to be moved,

In combination, an electric motor, a

a latch adapted antomaticallyto position, means for automatically tie-energizmg said magnet winding whensaid switcn is in running position, and a magnet adanted when energized tc disengage said latch.

4. in combination, an electric motor, starting switch therefor arranged to return automatically to 0d position, a resistance controlled by said switch, a magnet winding adapted to move said switch to running posi tion, a retardin device operatively connected to said switcl i, a latch adapted automatically to engage and to retain said switch in running position, means for automatically tie-energizing said magnet windin when the switch is in running position, an a magnet winding adapted when energized to disengage said latch.

-5. in combination, an electric motor, a starting switchtherefor arranged to return automatically'to off position, a magnet winding adapted to move said switch to running position, means at a distancefor energizing said ma at to start said motor, means for automatically deenergizing said magnet winding when theswitch is in running position, alatch adapted automatically toengage and to retain said switch in running position, a second magnet windin adapted when energized to disengage said%atch, and means at the distant oint for energizing said second magnet winding to stop the motor.

6. In combination, an electric motor, a starting switch therefor arranged toreturn automatically to off position, a resistance controlled by said switch, a magnet winding adapted to move said switch torunning position, a retarding device operatively connected to said switch, means at a distant point for energizing said magnet winding to start the 9 5 motor, means for automaticall de-energizing said magnet windin when t e switch is in running position, a atch adapted automatically to engage and to retain the switch in running position, a second magnet windin 10o ada te latcli,

d when energized to disengage sai and means at the distant point for energizing said second magnet winding to stop the motor.

In witness whereof, I have hereunto set myhand this 24th day of May, 1906.

- CHARLES D. KNIGHT. Witnesses:

Bantam: B. HULL,

HELEN Unseen.

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