US1341651A

US1341651A - Sylvania

Info

Publication number: US1341651A
Authority: US
Publication date: 1920-06-01
Anticipated expiration: 1937-06-01

Description

E. S LAMMERS, JR.

' MOTOR CONTROL SYSTEM.

APPLICATION FILED NOV. 3. 1917.

Patented J une 1, 19 20.

UNITED STATES TENT OFFICE.

EDWIN S. LAMMERS, JR., 0F WILKINSBUBG, PENNSYLVANIA, ASSIGNOR TO WESTING- HOUSE ELECTRIG AND MANUFACTURING- GOMPANY, A CORPORATION OF PENN- SYLVANIA.

MOTOR-CONTROL SYSTEMI.

Application filed November 3, 1917.

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 lVillrinsburg, in the county of Allegheny and State of Pennsylvania, have invented a new and useful Improvement in Motor-Control Systems, of which the fol lowing is a specification My invention relates to systems of control and particularly to systems of control for governing the operation of rolling mills having a plurality of sets of tandemmounted rolls.

One object of my invention is to provide a system of control of the above-indicated character that shall automatically control the speeds of the various sets of operating rolls in accordance with the tension, between sets of rolls, of the material passing through the mill.

In a mill having a plurality of tandemmounted sets of rolls that are adapted to simultaneously efl'ect reductions on the same piece of material which is passing through the mill, it is essential to operate each succeeding set of rolls at a higher speed than the preceding set of rolls, in order to take care of the increased length of the material that is being rolled. At the present time, the various sets of rolls of a continuous mill are connected to motors by different gear ratios in order to eliect a rough adjustment or" the speed, and the finer adjustments are effected manually by means of resistors in the form of the usual field rheostats that are associated with the respective sets of rolls. The above means for governing the speeds of the various sets of operating rolls is troublesome and inconvenient, inasmuch as each set of rolls requires constant attention in order to prevent either buckling or stretching between the various sets of rolls, of the material passing through the mill. Moreover, the changing of the rolls, in a mill for rolling different shapes and sizes, necessitates a complete change in the speeds of the various sets of rolls, which is somewhat troublesome to effect by the manual means new in service.

In a control system constructed in accordance with my invention, sets of guide rolls are located between the sets of operating rolls and are provided with contact means Specification of Letters Patent.

Patented June 1, 1920.

Serial No. 200,007.

ton automatically governing the speeds of the various operating rolls in accordance with the tension, between the sets of rolls, of the material that is passing through the mill. Thus, if the material tends to buckle between two sets of rolls, the means associated with the guide rolls between the operating rolls is operated in a manner to increase the speed of the forward set of rolls, and, in case the material is stretched between two sets of operating rolls, the speed of the forward set of rolls is reduced by the means associated with the guide rolls. It is impracticable to vary the speed of the forward set of rolls beyond predetermined limits, after which limits, the speed of the rear set of rolls is varied by the means associated with the guide rolls between the sets of operating rolls.

The single figure of the accompanying drawing is a diagrammatic view of a control system constructed in accordance with my lnventlon.

Referring to the drawing, a. mill embodies three sets of rolls 2, 3 and 4 which are adapted to operate simultaneously upon a strip of material 5. A plurality of motors 6, 7 and 8, respectively comprising armatures 9, 10 and 11, series field windings 12, 13 and 1 1, and shunt field windings 15, 16 and 17, are respectively connected to the sets of rolls 2, 3 and 4;.

A set of guide rolls 18 is provided between the sets of operating rolls 2 and 8, and a set of guide rolls 19 is provided between the sets of operating rolls 3 and 41. The guide rolls 18 are mounted on a carriage 21 which is slidably disposed in a housing 22, and are maintained in a normal position by means of springs 23. A switch 241- is asso ciated with the carriage 21, in a manner to bridge the contact terminals 25, in case the guide rolls 18 of the carriage 21 are raised by the material 5 buckling between the sets of rolls 2 and 3. A switch 26 is also associated with carriage 21 for bridging contact terminals 27 whenever the guide rolls 18 and the carriage 21 are forced downwardly by the material 5 being stretched between the sets of operating rolls 2 and 3. The set of guide rolls 19 is mounted upon a carriage 28 and is resiliently supported in a manner similar to that set forth in describing the construction of the support for the guide rolls 18. The carriage 28, which supports the guide rolls 19, is provided with two switches 29 and 30, which are adapted to operate in a manner similar to the operation of the switches 24 and 26, for bridging contact terminals 31 and 32. The central portions of the carriages 21 and 28 are normally a little above the horizontal pass-line between the rolls 2, 3 and 4.

A plurality of

contact devices

33, 34 and 35, which are controlled by the switches 24, 26, 29 and 30, are respectively associated with the shunt field windings 15, 16 and 17, for automatically governim the speed of the motors 6, 7 and 8. The contact device is controlled also by the push buttons 36 and 37.

The normal positions of the guide rolls 18 and 19 are above the plane of the main rolls 2, 3 and 4, and the sheet of metal is, accordingly, raised above the plane of the main rolls by the guide rolls. The metal is curved with the convex surface uppermost, under normal conditions. When the metal buckles, the length of the curved portion increases and the height of the loop increases correspondingly. When the metal is under tension, the length of the conve. :ly-curved portion is decreased and the peak of the curve and the positions of the guide rolls are correspondingly lower.

The contact device 33 embodies rheostat 38 comprising the usual resistor and having a contact arm 39 which is rigidly mounted upon a shaft 49. Two ratchet wheels 41 and 42 are rigidly mounted on the shaft and are respectively operated by means of a pawl 43 that is pivotally mounted on an arm 44 and a pawl 45 tl at is pivotally mounted on an arm 46. The arms 44 and 46 are rotatably mounted on the shaft 49 and are maintained in a normal position by means of suitable springs 47 which are connected to arms 48 and 49 that are respectively joined to the pawls 43 and 45. An electro-magnet 50, that embodies an energizing coil 51, a contact member 52 and a core member 53, which is pivotally oined to the arm 49, and a similar electromagnet 54, that embodies an energizing coil a contact member 56 and a core member 57, which is pivotally joined to the arm 48, are provided for operating the pawls 45 and 43 and the ratchet wheels 42 and 41. A switch 59 is adapted to bridge contact terminals 60, when in a normal position, and to engage a contact terminal 61 when the arm 62, associated with the switch 59, is operated by a pin 63, which is mounted on the contact arm of the rheostat 38. A switch 64, which is similar in construction to the switch 59, is adapted to bridge contact terminals 65 when in a normal position, and to engage a contact terminal 66 when the arm 67, associated therewith, is operated by means of the pin 63, which is mounted on the contact arm 39. The switches 59 and 64 are pivotally mounted in such manner that the weights of the arms 62 and 67 maintain the switches in engagement with contact terminals 60 and 64, under normal conditions.

The contact device 34 embodies a rheostat 70, which is similar in construction to the rheostat 38 in the contact device 33, and a contact arm 71, which is rigidly mounted upon a shaft 72. Two ratchet wheels 73 and 74, which are operated by means of pawls 75 and 76, are rigidly mounted on a shaft 72 in a manner similar to that set forth when describing the construction of the ratchet wheels 41 and 42 of the contact device 33. The pawls 75 and 7 6 are respectively operated by means of electromagnets 77 and 78. Two switches 79 and 80, having arms 81 and 82 associated therewith, are positioned to respectively engage the contact terminals 83 and 84, when in a normal position, and to engage the contact terminals 85 and 86 when the arms 81 and 82 are operated by the pin 87, which is mounted on the contact arm 71.

As the contact device 35 is similar, in construction, to the contact devices 33 and 34, a detailed description thereof is deemed unnecessary.

Assuming the apparatus of the system to be in the position shown, and the motor 7, which is connected to set of rolls 3, to be operated at such speed as to cause the material 5 to buckle between the sets of rolls 2 and 3, the guide rolls 18 and the carriage 21 are raised, and the switch 24 is operated to bridge the contact terminals 25. Thus, a circuit is completed from the negative supply conductor 88 through the switch 89, contact terminals 25-which are bridged by the switch 24contact terminals 83-which are bridged by the switch 7 9-contact members of the electromagnet 78, and the coil of the electromagnet 78 through the switch 89 to the positive supply conductor 90. The electromagnet 78 is moved downwardly to break this circuit of the energizing coil of the electromagnets 78 and to effect a pivotal movement of. the pawl 76 into engagement with the ratchet wheel 74 in a manner to rotate the contact arm 71 in a counter-clockwise direction. Thus, portions of the resistor of the rheostat are inserted in circuit with the shunt field windings 16 of the motor 7 by the operation of the contact arm. Inasmuch as the Contact members of the electromagnet 7 8 break the circuit of the coil of the electromagnet 78, the contact arm 71 of the rheostat 70 will be intermittently operated in a counter-clockwise direction to introduce sections of the rheostat 70 in circuit with the shunt field winding 16 until the set of rolls 3 are operated at such speed as to take up the buckle in the material 5 be tween the sets of rolls 2 and 3, and to disengage the switch 24 from the contact members 25.

In case the rheostat arm 71 is operated in a counter-clockwise direction by means of the electromagnet 78, until the pin 87 engages the arm 81 to disengage the switch 79 from the contact members 83 without increasing the speed of the set of rolls 3 sufficiently to reduce, the buckling efi'ect on the material 5 between the set of rolls 2 and 3, a circuit is completed for reducing the speed of the motor 6. The circuit which is thus completed may be traced from the negative supply conductor 88 through the switch 89, contact members 25--which are bridged by the switch 24the switch 79, contact member 85, contact members 65which are bridged by the switch 64contact members 56 of the electromagnet 54, the coil 55 and the switch 89 to the positive supply conductor 90. The electromagnet 54 is operated to break its energizing circuit and to move the pawl 43 pivotally into engagement with the ratchet wheel 41. Thus, the contact arm 39 is rotated in a clockwise direction in order to short-circuit portions of the resistor of the rheostat 38, which is in circuit with the field winding 15, and thereby reduce the speed of the motor 6 and the set of rolls 2. The intermittent operation of the electromagnet 54 is continued until the speed of the motor 6 and the set of rolls 2 is sufficiently reduced to prevent the buckling effect of the material 5 between the rolls 2 and 3, and to disengage the switch 24 from. the contact members 25.

In case the motor 7 and the set of rolls 3 are operated at a speed sufiicient to stretch the material 5 between the sets of rolls 2 and 3, the switch 26, which is associated with the carriage 21 and the guide rolls 18, is forced downwardly to bridge the contact terminals 27. A circuit is completed from the negative supply, conductor 88 through the switch 89, contact terminals 27which are bridged by the switch 26contact terminals 84- which are bridged by the switch 80contact members of the electromagnet 77 and the energizing coil of the electromagnet 77 through the switch 89 to the positive supply conductor 90. The electromagnet 77 operates, causing a pivotal movement of the pawl 75 into engagement with the ratchet wheel 73, to rotate the contact arm 71 and thereby short-circuit portions of the resistor of the rheostat which is in circuit with the shunt field winding 16. Thus, the speed of the motor 7 and the set of rolls 3 is reduced until the switch 26 is disengaged from contact with the contact terminals 27.

In case the contact arm 71 of the rheostat 70 is rotated in a clockwise direction until the pin 87 engages the arm 82 of the switch 80 without reducing the speed of the set of rolls 3 sufficiently to prevent the stretching of the material 5 between the sets of rolls 2 and 3, a circuit is completed through the switch 80 for operating the electromagnet 50 of the switching device 33 in order to increase the speed of the motor 6 and the set of rolls 2. The circuit through the electromagnet 50 may be traced from the supply conductor 88 through the switch 89, contact terminals 27which are bridged by the switch 26-switch 80, contact terminal 86, contacts terminals 60which are bridged by the switch 59-c0ntact members 52 of the electromagnet 50, the energizing coil 51 of the electromagnet 50 and the switch 89 to the positive supply conductor 90. The pawl 45 and the ratchet wheel 42 are intermittently operated, as above described, by means of the electromgnet 50 to rotate the contact arm 39 in a counter-clockwise direction until a sufficient portion of the resistor controlled thereby is included in circuit with the shunt field winding 15 to properly increase the speed of the motor 6 and of the set of rolls 2. Thus, the tension on the material 5 between the sets of rolls 2 and 3 is so reduced as to permit the switch 26 to break contact with the contact terminals 27.

The switches 29 and 30, which are associated with the guide rolls 19 between the sets of rolls 3 and 4, are operated in a manner similar to the operation of the switches 24 and 26 for controlling the speed of the motors 6, 7 and 8 in order to prevent buckling or stretching of the material 5 between the sets of rolls 3 and 4. Moreover, it may be noted that, although my system has been described in connection with a mill having but three sets of rolls, the same is adapted for service on a mill having any number of sets of rolls.

In case it is desired to increase the speed of the motor 6 and the set of rolls 2 at will, the push button 36 is closed to intermit tently complete a circuit through the elec tromagnet 50 and thus rotate the contact arm 39 in a counter-clockwise direction so as to insert resistance in circuit with the shunt field winding 15. In case it is desired to reduce the speed of the motor 6 at will, the push button 37 is closed to intermittently complete a circuit through the electromagnet 54, and thus rotate the contact arm 39 in a clockwise direction so as to eX- clude portions of the resistor of the rheostat 38 from the circuit 01: the field winding 15.

It may be noted. that, if so desired, the contact arms of the rheostat associated with the

contact devices

33, 34 and 35 may be controlled by pilot motors, as is described in my copending application, Serial No. 200,008, filed November 3, 1917 Modifications in the system and arrangement and location of parts may be made within the spirit and scope of my invention, as expressed in the appended claims.

I claim as my invention:

1. The combination with a pair of ma chines for treating material and a guide member for said material, of means controlled in accordance with the position of said guide member for controlling the speeds of said machines.

2. The combination with a pair of rolls, a driving motor for each of said rolls, and a guide roll between said rolls, of means controlled in accordance with the position of said guide roll for respectively controlling the speeds of said motors under dillerent predetermined conditions.

2:3. The combination with a pair of machines for treating material, a driving motor for each machine, each of said motors having a shunt ficldmagnet winding and a resistor in series therewith, of means con trolled in accordance with the position of said material for first inserting one oil said resistors into circuit and then short-circuit- .ing the other of said resistors.

l. In a system of control for a pair of tandem-mounted sets of rolls the combination with a pair of motors respectively connected to the sets of rolls, of means controlled by the material being rolled for controlling the speed of one of said sets of rolls and means controlled by said controlling means for controlling the speed of the other of said sets of rolls.

5. In a system of control for a mill having a plurality of sets of rolls for continuously rolling a single piece of material, the com.- ination with a plurality of motors severally connected to the various sets of rolls, and a guiding member disposed between adjacently disposed sets of rolls, of rheostats controlled by the guiding member for governing the speed of adjacent sets of rolls in accordance with the tension on the material between the sets of rolls.

6. In a system of control for a plurality or" tandem-disposed sets of rolls, the combination with a plurality of motors severally associated with the various sets of rolls, and rheostats for controlling the operation of said motors, of means controlled by the tension ol the material between the sets of rolls for governing the operation of said rheostats in a predetermined order.

7. In asystem of control for a plurality of tandem-disposed sets of operating rolls, the combination with a plurality of motors severally connected to the various sets of rolls, and a set of guide rolls disposed between the various sets of operating rolls, of means controlled by each set of guide rolls for governing the speed of the motors connected to adjacent sets or operating rolls and the speed of the motors connected to all preceding sets of rolls.

8. In a system of control, the combination with a plurality of tandem-disposed operating rolls and guide members located between the sets of operating rolls, of means controlled in accordance with the position of each of the guide members for governing the speeds of operation of the adjacently disposed operating rolls.

9. The combination with a series of rolls for treating material, of means controlled in accordance with the position 01 said material for controlling the speeds of a plurality of said rolls after said material has been treated by said plurality of rolls.

10. The combination with a pair of sets of metal-working rolls, and a driving motor for each of said sets of rolls, of a carriage between said sets of rolls having a pair or guide rolls for the metal and a pair of switch. members for respectively effecting an increase and a decrease in the speed of ie or" said motors in accordance with the buckling and the stretching of the metal.

In testimony whereof I have hereunto subscribed my name this 12th day of Oct, 1917.

EDWIN s. LAMA mes, JR-