US1382988A - Motor-control system - Google Patents

Description

E s. LAMMERS, JR-

MOTOR CONTROL SYSTEM. APPLICATION FILE D NOV. 3, 1917.

1,382,988. Patented June 28, 1921.

WITNESSES: mvsmoa E4. flfJwr g Edwin S. La mmers fit UNITE STATES fPA'TENT. OFFICE.

EDWIN S. LAMME'BS, JR, 0! WILKIN'SBURG, PENNSYLVANIA, ASSIGNOR TO WEST- INGHOUSE ELECTRIC PENNSYLVANIL MANUFACTURING COMPANY, A CORPORATION OF Moron-common svsrnn.

Specification of Letters Patent. Patented June 28, 1921 Application filed November 8, 1917. Serial No. 200,008.

To all whom it may concern:

Be it known that I, EDWIN S. LAMMERS, Jr., a citizen of the United States, and a resident of Wilkinsburg, in the count of Allegheny and State of Pennsylvania, ave invented a new and useful Improvement in Motor-Control Systems, of which the following is a specification.

My invention relates to systems of con-- the form of coils upon a drum, and, moreover, it is found that the quality of the material beingrolled is materially increased by keeping a predetermined tension on the strIip or rod while the same is being wound. n many of the mills now in service, the winding drum is geared to the last set of rolls in order to be operated thereby. Thus, as the diameter of the coil of wound material increases, the tension on the material be-' gear is provided in the gear connection, but

such a slip ar has proved to be very unsatisfactory 1n operation. 1 1

In a control system constructed in accord ance with my invention, the winding drum is connected to a separate motor, the speed ..of which is controlled in accordance with and a shunt-field winding 4, is connected to a winding drum 5 in any convenient manner by means of a clutch 6 which is controlled by an operating handle 7. A- doublethrow switch member 8 is connected to the operating handle 7 by an arm 9 in order to be operated thereby, for a purpose to be set forth hereinafter.

A tplilot motor 10, having an armature 11 i and old windings 12 and 13, is provided for governing the operation of an arm 14 of a rheostat 15 the resistor of which is included in the circuit of the shunt-field winding 4. A switch 16, which is included in the circuit of the field winding 12, and a switch 17, which is included in the circuit of the field winding 13, are adapted to be operated by the rheostat arm 14 in the respective extreme positions thereof. The switches 16 and 17 are normally maintained closed by means of the springs 18 and 19 or by any other approved means.

A starting resistor; 20, having a contact arm21, is provided in circuit with the motor 1. A compound-wound relay 22, having a series coil 23 disposed in series with the motor 1 and a shunt coil 24, is provided for governing the operation of the pilot motor 10. The relay 22 is adapted to bridge contact terminals 25 in the released position, and, in an-0perative position, is adapted to brid e contact terminals 26. The switch memier 8 is adapted to bridge contact terminals 27 and 28 when the motor 1 is disconnected from the winding drum- 5 and to bridge contact terminals 27 and 29 when the motor. 1 is' connected to the windin drum 5 by means of the clutch 6. A switc 30 is provided for connecting the system to any suitable source of direct current.

Assuming the system to be in the condition illustrated on the drawing, and the motor 1 'to' be connected to the source of power 31, with the starting resistor 20 excluded from circuit b means of the rheostat arm 21, a section 0 material from a set of rolls 33 may. be connected to the winding drum 5 in order to-be wound thereon. When the material 32 isconnected to the winding drum 5, the clutch 6 is operated to connect the motor 1 to the drum 5 and to bridge contact terminals 27 and 29 by means of the switch member '8. The motor 1 is operated at a slow speed for winding the material 32 upon the drum 5, and a circuit is completed for the pilot motor 10, which may be traced from the. positive supply conductor through the contact terminals 27 and 29, which are bridged by the switch member 8, contact terminals 25, which are bridged by the contact member of the relay 22, switch 16, field winding 12 and armature 11 to the negative supply conductor. The two field windings 12 and 13, which are associated with the pilot motor 10, are adapted to rotate the motor in opposite directions when severally energized, the energization of the field winding 12 cffecting the rotation of the 'motor 10 in a counter-clockwise direction, and the energizati-on of the field winding 13 efiecting the rotation of the pilot motor 10 in a clockwise direction' Thus, when a circuit for the motor 10 is closed through the field winding 12, as above set forth, the rheostat arm 14 is operated in a counter-clockwise direction in order to insert sections of the resistor of the rheostat 15 in circuit with the shunt-field winding 4. of the motor 1.

The speed of the motor 1 and the tension on the material 32 which is being wound on the drum 5 are increased in accordance with the resistance inserted in circuit with the field winding 4 by means of the rheostat 15, and, moreover, the current taken by the motor 1 varies directly with the tension on the material 32 between the winding drum and the rolls. When the tension on the material 32 has been increased to a predetermined value, the compound relay 22 is operated by means of the increased current flowing through the series coil 23 to break the connection between the contact terminals 25 and to bridge the contact terminals 26. Thus, the circuit previously traced through the field winding 12 and the pilot motor 10 is broken and a circuit is completed through the field winding 13 and the pilot motor 10, which may be traced from the positive supply conductor through the contact terminals 27 and 29, which are bridged by the switch member 8, contact terminals 26, which are bridged by the contact member of the relay 22, switch 17,, which has been closed by reason of the rheostat arm 14 being moved from its extrenie position, field winding 13 and-armature 11 to the negative supply conductor. Thus, the rheostat arm 14 is operated in a clockwise direction in order to short-circuit portions of the resistor of the rheostat 15 from the circuit of the shunt-field winding 4 and thus reduce the speed of the motor 1 and the tension on the material 32 which is being wound upon the drum 5. In case the load on the motor 1 is reduced a predetermined amount, the compound relay 22 is released in order to again increase the speed of the motor and the tension on the material 32.

lVhen the clutch 6 is operated by the arm 7 to disconnect the winding drum 5 from the motor 1, the switch member 8 is operated to bridge the contact terminals 27 and 28 ,and to complete a circuit through the field winding 13 and the pilot motor 10 in order to 0perate the rheostat arm 14 in a counter-clockwise direction until the switch 17 is operated thereby and the resistor of the rheostat 15 within the spirit and scope of my invention,

and such modifications are intended to be covered by the appended claims.

1 claim as my invention:

1. In a system of control, the combination with a motor having an armature and a shunt-field winding, and a source of energy for said motor, of a relay having a pair of actuating coils respectively in series with said armature and connected to said source, and means controlled thereby for varying the energization of said shunt-field winding in accordance with the load conditions of the motor. said source-connected coil being energized only when said other coil is energized below a predetermined degree. a

2. The combination with a main motor having an armature, a shunt-field-magnet winding and a resistor in series with said winding, of a pilot motor for controlling said resistor having a pair of field-magnet windings for respectively efi'ecting the operation of said pilot motor in opposite directions, and a two-position switch having an actuating coil in series with said armature and a second actuating coil that is energized only when the switch is in one position, said switch being adapted to energize one of said pilot-motor field-magnet windings in each of its positions.

3. The combination with a main motor having a shunt-field-mag net winding, a resistor n series therewit r and a controller for sa1d resistor, of a pilot motor for said controller having a pair of field-magnet windings for respectively effecting the operation of said pilot motor in opposite directions, and a pair of normally closed switches, one in circuit with each of said pilotqnotor windings, and one of which is adapted to be opened when said controller occupies one position and the other of which is adapted to be opened when said controller occupies another position.

4. The combination with an operating mechanism, a driving motor therefor having armature and; field-magnet windings, and means for connecting said motor to said mechanism, of means comprising a variable resistor and a pilot motor controlled in ac-' cordance with the position of said connecting means for increasing the excitation of said field-magnet winding in accordance with the load upon said motor and for antomatically decreasing the excitation of said field-magnet winding upon the disconnecting of said motor from said mechanism.

5. In a system of control for a winding drum, the combination with a motor for op- .erating the drum and a clutch for connecting said motor to said drum, said motor having a variable resistor associated therewith for controlling its speed, and a controller for said resistor having a normal position, of means operable when said clutch is in its operative position to actuate said controller from said normal position when the load, upon said motor is increasing and to actuate said controller toward said normal position when the load, upon said motor is decreasing, said means being operable to automatically actuate said controller'toward said normal sition when said clutch is in its inoperative positlon.

'6. In a system of control for a windingdrum, a motor having an armature and a field winding for operating the drum, a rheostat for governingthe energization of the field winding, and a pilot motor controlled by a current relay in circuit with the terial on the drum at a given tension, of

a means for disconnecting the motor from the drum and for simultaneously effecting the operation of said pilot motor to reduce the speed of the main motor.

In testimony whereof, I have hereunto subsicribed my name this 12th day of Oct., 191

EDWIN s. LAMMERS, JR.

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