US2343335A - Electrical control circuit - Google Patents

Description

March 7, R H SMITH T AL ELECTRICAL CQNTROL CIRCUIT Original Filed Aug. 17, 1940 INVENTOR. K0500: H5M/n/ [mm 5 Name 6 160A M. DUNN/N6 Patented Mar. 7, 1944 ELECTRICAL CONTROL CIRCUIT Roscoe H. Smith and Lloyd E. Miller, Cleveland,

Ohio, and Leon M. Dunning, Boston, Mass, assignors to The Reliance Electric and Engineering Company, a corporation of Ohio Original application August 17, 1940, Serial No. 353,102. Divided and this application April 21, 1942, Serial No. 439,924

7 Claims.

This application is a division of our application Serial No. 353,102, filed August 17, 1940, for Electrical control systems. 1

Our invention relates in general to electrical control circuits and more particularly to electrical control circuits including motors and generators connected to drive a load which has a wide speed variation such, for example, as a cloth printing machine.

The main drive for the cloth printing cylinder is applied to the several engraving rolls by a suitable gearing arrangement. The pressure of the engraving rolls on the large printing cylinder drives the latter by friction. In actual practice the circumferences of the engraving rolls vary between 16 inches to 24 inches for different lengths of patterns being printed. Accordingly, .the linear speed of the printing machine cylinder varies from a given speed of the main drive, de pending upon the circumferences of the engraving rolls. At the maximum linear speeds the drive is designed to provide at least 300 yards per minute, which is made available even with the minimum size engraving rolls; namely, the 16 inch circumference rolls, and at the minimum linear speeds the drive is designed to give as low as yards per minute for threading or matchingup purposes, which is made available with the maximum size engraving rolls; namely, the 24 inch circumference rolls. Although this appears to be a to 1 speed range, it is actually to l by reason of the variations in the diameters of the engraving rolls. In threading the machine, the operator may run it at a low speed by setting the electrical control at run slow condition. For production printing speeds the operator operates the machine under run fast condition.

An object of our invention is to provide for selectively energizing the main motor which drives the engraving rolls and the printing cylinder from a low voltage and a normal voltage generator to obtain the wide speed variations.

Another object of our invention is to provide for electrically energizing the main motor from the low voltage generator under the run slow a condition and to provide for energizing the main 'motor from the normal voltage generator under the higher speeds of the run fast condition.

Another object of our invention is to provide 1' or preventing the main driving motor from being subjected to an electrical jar upon the transition from the low voltage generator to the normal voltage generator.

Another object of our invention is to provide for making the transition from the low voltage generator to the normal voltage generator, and vice versa, at a point or condition where the voltages of the two generators are relatively close together.

Another object of our invention is to provide for making the transition from the low voltage generator to the normal voltage generator, and vice versa, at a point or condition where the voltages of the two generators are relatively close together while the voltages of both generators are changing.

Other objects and a fuller understanding of our invention may be had by referring to the following description and claims, taken in conjunction with the accompanying drawing, in which:

The figure shows a diagrammatic illustration of our electrical control circuit, the figure comprising the only view of the drawing.

The figure has been made by taking the divisional subject matter from Figures 3, 4 and 5 of our application Serial No. 353,102 hereinbefore mentioned, and in doing this the corresponding parts are designated by the same reference characters, except that the reference characters which designate the conductors in the figure of the present application do not correspond to the conductors designated in the Figures 3, 4 and 5 of our application Serial N 0. 353,102.

With reference to the figure, the printing cylinder is indicated generally by the reference character l6 and is driven by a main driving motor 54 through the plurality of engraving rolls 1?. As explained hereinbeiore, the speed variation from low speed to high speed may be as much as 45 to 1 and to take care of this Wide variation in speed, we arrange for selectively connecting the main motor 54 to a threading or crawl generator '11 or to a main generator 76. In other Words, for slow speed operation the threading generator 11 supplies energy for operating the main motor 54 and for production purpose the main motor 54 is energized from the main generator 16. An alternating current motor 82 is arranged to drive the main generator 15 as Well as an exciter 8!, all of which may be suitably driven by the same shaft construction. The threading or crawl generator 11 is arranged to be driven by an alternating current motor 33. The two alternating current motors 82 and 83 may be suitably energized from an alternating current source 84, in which the motor 82 ma be connected to the alternating current source through the set of contactors 85 upon the closing of the switch 231 and in which the motor 83 may be suitably connected to the alternating current supply source through a contactor I 45 upon the closing of the switch 238. The exciter BI supplies current for governing the control circuits as well as for the fields of the generators 1'5 and 11, the field for the main motor 54 and the field for the exciter itself. As illustrated, the field I3I for the exciter is connected across the conductors 21 and 23 energized by the exciter and governed by a resistor I32 of the adjustable type. The field SI for the main generator 1B is energized by a circuit which extends from the exciter conductor 28 to a conductor 53, the field winding 9!, and a conductor to a variable resistor 94 of the motor operated rheostat I31 and to the conductor 2?. The circuit for energizing the field 91 for the threading generator 11 may be traced as follows: beginning with the exciter conductor 23, current flows through a conductor 52, the field winding 91, and a conductor 53 to the variable resistance Iiii! ofthe motor operated rheostat I31 and to the conductor 21. The circuit for energizing the field winding 95 for the main motor 54 extends from the exciter conductor 28 through the conductor 55, the winding 95 and the illustrated adjustable resistor 51. The generated voltage ran e for the threading generator 11 is lower than the generated voltage range for the main generator 15. However, the upper portion of the range .for the threading generator 11 overlaps the lower portion of the voltage range for the main generator 15.

The selection'as-t'o whether the crawl or thread ing generator 11 or the main generator 16 supplies current to the main motor is governed by the transition relays I59 and 23L When the transition relay I59 is energized the main motor 54 is connected in circuit relationwith the threading generator 11 through a circuit which may be traced as follows: beginning with the conductor It the circuit extends through the armature of the threading generator 11, the conductors II and I2,'the contacts I60 of the relay I59, and the conductors I3 and I 4 through the opposite terminal of the main motor 54. When the transition relay 23! is energized the main motor 54 is connected in circuit relation with the main generator 16 and the circuit may be traced as follows: beginning with the conductor III the circuit extends through a conductor 2c, the armature of the main generator 15, the conductors 2| and 22, the contacts 233 of the relay 23 i, and the conductors 23 and 24 to the opposite side of the motor 54. Under a dynamic breaking circuit, the generators 16 and 11, are both disconnec'ted from the armature of the main motor 54 and the armature of the main motor is connected in a closed circuit including a resistor 3!. The closed dynamic breaking circuit extends from conductor I it through the conductor 20, the resistance 33!, the conductor 25, the contacts 299 of the relay I13 and the conductors 26, '24 and I4 to the opposite side of the motor 54.

The motor operated rheostat I31 which controls the operation of the circuits is driven by a motor 564 through a rack and pinion drive I353. (The motor operated rheostat I31 and the motor 544 which drives it may be the same as that substantially shown and described in our parent application, Serial No. 353,102, filed August 17, 1940.) As illustrated diagrammatically, the motor S lt may be controlled by a run slow contacting device I49 or a run fast contacting device I55. A stop contacting device I41 is positioned in advance of the run slow contacting device I49 rheostat I 31.

ductor 28.

and the run fast contacting device I50 and is arranged to arrest the operation of the control system. The stop contact device and the run slow and the run fast contact device as well as the motor 544 for the motor operated rheostat I31 are diagrammatically illustrated as being connected across the exciter conductors 21 and 28.

In starting the equipment in operation, the run slow contact device I49 is actuated which establishes a circuit ior energizing the dynamic breaking relay I13 through a circuit which extends from the'exciter conductor 21, the conductor 3|, the winding of the relay I13, and conductor 32 to the run slow Contact device I4Q. In the run slow position the motor operated rheostat I31 is in the position shown in the drawing with the movable contact member I39 positioned in the standstill location, In other words, the motor 544 which drives the motor operated rheostat I31 is inactive under the run slow condition. The energization of the dynamic breaking relay 113 opens the contacts 299 to remove the dynamic breaking circuit and closes the contacts 509 for establishing a circuit for energizing the transition relay I59. The circuit for thetran'sition relay I59 may bedescribed as follows: beginning with the exciter conductor 21 the circuit extends through the conductor '33, the winding of relay I59, the conductor 34, the contacts 5I51o'f the relay 23L the conductors 35 and 35, the contacts 5i8'of th'erelay II I, the conductor 31,'the contacts 569 of the dynamic breaking relay I13, and the conductor 38 to the contact member '6'4I of the motor operated 'rheo'stat and. then through the exciter conductor 23. The ene'rgization of the transition relay I59 connects the main motor 54 in circuit relation with the threading generator 11 through the closure of the contacts I513. The speed at the main motor 54 operates under the run slow condition of the circuits-mat be. as low as yards of cloth per minute for threading or matching-up purposes and :this may be governed by the amount of the resistance in the resistance element 180 of the motor operated Under the run slow condition, the motor operated rheostat I31 remains at the standstill location as shown in the drawing, under which condition the relays 223 and 4 are both energized. The relay 223 is energized through a circuit which extends from the exciter conductor 21, through the conductor M, the winding of the relay 223, and the conductor 42 to the contact member 658 of the motor operated rheostat whereupon the current flows to the exciter con- The operation of the relay 223 closes the contacts 653 and connects the two differential relays 221 and 228 across the conductor 21 of the main generator and the conductor II of the threading generator 11. The circuit for "energizing the relay 4! I extends from the exciteroonductor 21 through the conductor 39, the winding of the relay 4, and the conductor to the standstill contact member 433 of the motor operated rheostat I31 whereupon the current flows through the-exciter conductor 23.

Upon the actuation of the run fast Contact device I a condition is established for causing the motor 544 to operate the motor operated rheostat I31 and causing the movable member I39 to move to the right as shown in the drawing. As the movable member I39 moves to the right the resistance I is reduced and causes the voltage of the generator 11 to gradually increase. By the time that the movable member I 39 substantially reaches the contact member 54!, the voltage of the threading generator 11 has substantially reached the voltage of the with the exciter conductor 27, current flows through the contacts 65I of the relay I59 which is now de-energized, the conductor 43, the winding of the relay 23I, the conductor 44, the contacts 841 of the relay 228, the conductor 45 to the contact member 642 of the motor operated rheostat whereon the current flows to the exciter conductor 28. Inasmuch as the circuit for energizing the transition relay 23I extends through the contacts 641 of the relay 223, the circuit is not actually established until the relay 228 becomes sufliciently de-energized to close the contacts 547. In the actual operation of our circuit, we preferably hold the contacts 641 open until the difference in voltage generated by the threading generator 71 and the main generator I have been reduced to approximately 5 volts. We also preferably make the transition take place when the voltages of the two generators are in the neighborhood of or volts. The threading generator I? has a more rapid voltage rise than the main generator 16 during the early stages of the movement of the motor operated rheostat I33. The purpose of the relay 228 is to insure that the differential voltage between the threading generator TI and the main generator i3 is less than 5 volts, for example, durin the transition period in order to prevent too large a current disturbance upon the main motor 5 which would tend to damage the cloth being printed. After the transition takes place, the relay 223 is de-energized which opens the contact I353 for removing the differential relays 221 and 222 from the circuit. The disruption of the circuit which energized the relay 223 occurs when the movable member I39 of the motor operated rheostat passes beyond or to the right of the contact member 658 of the motor operated rheostat. In this application, when the movable member I39 is described as moving with reference to the contact members of the motor operated rheostat, it is to be understood that this is to be interpreted to mean that the contacts which are carried by the movable member move with reference to the contact members upon the motor operated rheostat. The speed at which the motor 54 operates under the run fast condition depends upon the setting of the motor operated rheostat which determines the voltage generated by the main generator 16. member I39 is moved to the extreme right hand position, the voltage of the main generator may be in the neighborhood of 230 to 240 volts.

In stopping the equipment, the run slow contact device I49 is preferably first actuated after which the stop contact device lfll may be operated to finally arrest the operation of the equipment. Upon actuation of the run slow contact device I49 the motor operated rheostat moves to the left until it reaches the standstill position as W'hen the movable shown in the drawing. As the movable member I39 of the motor operated rheostat moves to the left the voltage of the main generator T6 grad ually decreases. Upon the movable member I39 reaching the contacts 658 the circuit is again established for energizing the relay-223 which closes the contact 653 for including the relays 22'! and 228 in circuit relation with the two generators 76 and 11. After the movable member I39 passes the contact member 642 the circuit is disrupted which formerly energized the relay 23I and thus the motor 54 is disconnected from circuit relation with the main generator It. When the movable contact member I39 engages the contact member 6 H, a circuit is established for energizing the transition relay I58 which connects the motor 54 in circuit relation with the threading generator 71. The circuit for energizing the relay I59 extends from the exciter conductor 27, the conductor 33, the winding of the relay I59, the conductor 34, the contacts 5i5 of the relay 23! which is now de-energized, the conductor 35, to the point 48, the conductor 41, the contacts 664 of the relay 22?, th conductor 46, the contacts 509 of the relay i'lS, the conductor 38 to the contact members I54! of the motor operated rheostat whereupon the current flows to the exciter conductor 28. Upon the de acceleration of the equipment, the current for energizing the relay I59 upon reaching the point 48 does not flow through the contacts 5m 01 the relay 4! I for the reason that the relay Al I is energized only at the standstill position through the contact member 433. The object of making the current flow through the contacts 654 of the relay 22'! upon the energization of the relay I59 for the decelerating condition is that relay i551 is prevented from becoming energized until the voltage between the two generators has been decreased to a value substantially equal to 5 volts in order to prevent the electrical jar upon the motor during the transition from the main generator IE to the threading generator Tl. Therefore, in our circuit the transition relays I59 and 23I are not operated for transferring the load of the motor 54 to either one of the two generators I6 and Il until the voltage between the two generators has been decreased to the value of substantially 5 volts as determined by the operation of the protective relays 22'! and 228. When the equipment has been reduced in speed by actuating the run slow contact device I49, the movement thereof may be entirely arrested by actuating the stop contact device is? which operates the dynamic breaking relay I13 to ole-energize the relay I59 as well as establish the dynamic breaking circuit through the contacts 299.

Since the relay 4-H can be energized only in the standstill position of the motor operated rheostat I31 by current flowing through the contact member 433, the equipment cannot be started unless the motor operated rheostat is in the standstill position as illustrated in the drawing. As the motor operated rheostat partially moves to the right from the standstill position, the relay 4H becomes de-energiaed but the circuit for energizing the relay its still is maintained. through a holding circuit established by the contacts N5 of the relay 856 when once energised. The contacts I05 and the two conductors 23 3i) shunt the contacts 5I8 for the relay MI so that the relay 2 53 remains energized even though the contact is broken at the standstill contact to of the motor operated rhccstat as the movable member mo'ves "to the right. A holding/circuit -is also 76$?- tablished for the relay '23l for holding: the relay energized even though thecontactssfl of the relay 228 may be open as will be the casebe'f'ore the movable contact member 139 passes't'o the right of the contact member 658 which disrupts the circuit that energized the relay 2'23 forremoving the relays 221 and 223 from circuit relation with the two generators I6 and 'I'I. In other words, the relay 223 is disconnectedfrombeing energized just as soon as the movable contact member I39 of the motor operated'rheostat passes to the right beyond the point (i558 which means that the relays 228 and '22? are removed "from the differential voltage of the threading generator l7 and the main generator 16 under high speed operation where the differential voltage would be large and subject to windings of the relays 221 and 228 to the large current value. However, before the relay 228 is de-energize'dby the movable contact member 139 passing beyond the point 658, the holding circuit through the contact 661 is established for holding the relay 231 energized. The equipment continues to run with the main motor 54 energized from the main generator To and the speed to which the equipment attains is determined by'the setting of the motor operated rheostat I31.

Although we 'hav'ede'scribed our invention with a'certain degree of particularity, it is understoodthat the present disclosure has been'm'ade only by way of example and that numerous changes in the details of construction and the combinetion and arrangement of parts may be resorted to without departing from the 'spi'rit'and the scope of the invention as'hereinaftcr claimed.

No claim as our invention:

1. In control system, the combination of a motor having an armature anaemia, anormal voltage generator having an armature anda field, a low voltage generator having an armature and a field, electrical means for energizing the said fields, variable resistance means for varying the field excitation of the normal and low voltage generators, first circuit means for connecting the armature ofthe motor in circuit relation with the armature of the low voltage generator, Second circuit means for connecting th'earmatur'e of the motor in circuit relation with the armature of the normal voltage generator, selective control means for selectively operating the first and second circuit means, common means for operating the variable resistance means and the selective control means, and protective means responsiveto the voltage difference of the generators for also operating the selective control means.

2, In a control system fora cloth printing inachine having a printing cylinder and rolls, the combination of a motor for driving the printing cylinder and rolls, a normal voltage generator, a low voltage generator, said motor and said generators having an armature and a field, electrical means for energizing the said fields, first circuit means for connecting the armature of the motor in circuit relation with the armature of the low voltage generator, second circuit means for connecting the armature of the motor in circuit relation with the armature of the normal voltage generator, selective control means for sehaving electrical contact means for operating the selective control means, and protective means responsive to the voltage-difieriicecf the generators for also operating the selective control means.

3. Iii-a control system, the combination of a motor having an armature and a field, afirst generator having an armature and a field, a second generator having an armature and a field, electrical means for energizing the fields and varying the generated voltage of eachof the generators, the generated voltage range of one of said generators being lower than the generated voltage range of the other 'said generator, selective transition means for connecting the armature of the motor to either orient the ai'matui'es of the generators under changeable generated voltage conditions of both generatoraand means for causing the transition means to operate when the difference between the generated voltages of the two generators is at a low value.

4. In a control system, the combination of a motor having an armature and a field, a first generator having an armature and a field, a:second generator having an armature and a field, electrical means for energizing the fields, first circuit means including a first relay for connecting the armature oi the motor in circuit relation with the armature of the first generator, second circuit means including a second relay for connecting the armature oi the motor in circuit rela tion with the armature of the second generator, a motor operated rheostat for varying the field excitation of the generators, the generated voltage range of the first generator being lower than the generated voltage range of the second generator with the upper portion of the voltage range of the firstgenerator extending at least up to-the lowerportion of the voltage ran e of the second generator, a first selective circuit for operating the first relay to connect th armature oi the motor in circuit relation with the first generator, a second selective circuit for operating the second relay to connect the armature of the motor in circuit relation with the second generator, said motor operated rheostat having electrical contact means for sequentially governing the o eration of the first and second selective circuits, and difierential relay means responsive to the cliil'erence between the voltages of the generator for also governing the operation of the first and second selective circuits when the voltage diilerential between the two generators is at a low value.

5. In a control system, the combination of a motor having an armature and a field, a first generator having an armature and afield, a second generator having an armature and a field, electrical means for energizing the fields, first circuit means including a first relay for connecting the armature of the motor in circuit relation with the armature of the first generator, second circuit means including a second relay for connecting the armature of the motor in circuit relation "with the armature of the second generator, a motor operated rheostat for varying the field excitation of the generators, the generated voltage range of the first generator being lower than the generated voltage range of the second generator with the upper portion of the voltage range of the first generator extending at least up tothe lower portion of the voltage range of the second generator, a first selective circuit for operating the first relay to connect the armature of the motor in circuit relation with the first generaton a second selective circuit for operating the second relay to connect the armature of the motor in circuit relation with the second generator, said first selective circuit being connected through contact means on the second relay and said second selective circuit being connected through contact means on the first relay, said motor operated rheostat having electrical contact means for sequentially governing the operation of the first and second selective circuits, and dif ferential relay means responsive to the difference between the voltages of the generator for also governing the operation of the first and second selective circuits when the voltage differential between the two generators is at a low value.

6. In a. control system, the combination of a motor having an armature and a field, a first generator having an armature and a field, a second generator having an armature and a field, electrical means for energizing the fields, variable resistance means for varying the generator fields and thus the generated voltage of each of the generators, the generated voltage range of one of said generators being lower than the generated 5 voltage range of the other said generator, selective transition means for connecting the armature of the motor to either one of the armatures of the generators, means for causing the transition means to operate when the differential between the generated voltages of the two generators is at a low value, and common means for governing the operation of the variable resistance means and the selective transition means.

7. In a control system, the combination of a motor and a plurality of generators for selec tively supplying energy to the motor, said generators having different voltage ranges with a portion of each of their ranges substantially coinciding, selective transition means for selectively conmeeting the motor in circuit relation with the generators, and means for causing the transition means to operate when the voltage differential between the generators is at a low value.

ROSCOE H. SMITH. LLOYD E. MILLER. LEON M. DUNNING.

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