US1041137A - Motor-control system. - Google Patents

Description

R. H. MG'LAIN, MOTOR CONTROL SYSTEM.

APPLICATION FILED AUG.21 1911.

, "1, 1,137, Patented 001i. 15,1912.

34/ Q r F131]. 20 4 1 7 v v Lq ff Inventor- Robert H. McLain,

HisAttorney.

byMMl no a nnr H; new

'-. 'noronrcon-rnon SYSTEM.

' 'To qllwhomzttimay concern:

-B it known that I, Rosana? H.

itl'zeli oflfi the' United States, residing at ncc'tady, county of Schenectady, State colt-"New York, have. invented certain new i and useful I Improvements in M'otor-Control v "Systems, ofw'hich thefollowing is'a specification; y I

"Thisinventionrelatest0 means for controlling the operation-of an electric motor driving part'of amachine in such a manner .Ltha t-"itwill vary tl1e eXte-nt ofits operation I an icorresponde'nce with the movement of some other'element of said machine.

Q with the up'pcrior the lower roll, asthe case Jmay,be,-'in orderthat-"'itmay be rigidly backed upby saidroll and thus be enabled to sustainithe pressure when the platepasses j between it-andthe other roll. To reduce the thickness of thebillet to that which it is de 'sirecl'the plate shall have, the upper roll 1 must be lowered more or less after each pass ,of the plate. This operation, by reducing the space-between the upper and the lower rollin which the middle roll plays 35- .up and down, also necessitates some-- provision by which the means for shifting said iniddle roll shall be automatically varied in its'action to correspond with the, lessening r range of movement otsaidmiddle roll. in 40. the mill tow'hich my invention relates, the middle roll is shifted by an electric motor, running in one direction to raise said roll and inthe other direction to lowerit; As-

'sum ing' that-a given number of revolutions must be made to eflect the maximum shift of "the roll, it is evident that as the'range oi .moven'ient of said roll lessens, so also the number-of revolutions of said motor must lessen. v

The objectof my invention is to effect this result automatically by placing the motor under the control of the operator who handles the. upper roll. In brief, I employ two-limit switches, one geared to the screwdown mechanism of the upper roll and the Specification of Letters Patent. "Application men August 21, on. Serial No. 645,167.;

McLAin The invention is especially applicable to middle rollfmoves up or doWn into, contact .The sketch, Fig. 2,

STATESPATENT clarion, l orsonnnncranv, NEW YORK, Ass lotion TO eminent nLEc'rnIc .co v ranv, AcoRPonArIon or NEW YonK.

Patented Oct. 15,

other to'themiddle roll motor. Tworelays' control contactors which inturn control the motor circuit. One relay governs the motor when the roll is going up and the other relay when said roll is going down, and when both relays are down or up the motor will not run. If only one relay is up the motor can run, and that relay determines thedirection of rotation of the motor. The limit switches have their segments overlapping so that for a given number of segments and fingers nearly twice as many stations or positions can be obtained.

' The invention will be better understood from the following detailed description, reference being had to the accompanying drawing, in which-,- I

Figure 1 is a diagram of the circuits emt bodymg my system, and Fig. 2 is a (liagrammatic sketch of a three-high niill with the limiting switches and roll-sliiftinginotor.

Referring first to the sketch, Fig. 2, the three rolls 1, 2, 3 are seen. to be arranged in a vertical tier, roll 3 being thelowest and journale'd in stationary bearings. The upperroll 1 is arranged to be screwed down, the mechanism illustrated being a simple screw -fl and-hand wheel 5; though in practice more elaborate .mechanism is usually employed. Operatively connected to this sc'rewdown mechanism, whatever its char-. acter may be, is a limit switch 6, preferably in theform of a drumof insulating material carrying conducting segmentswhich 00- operate with stationary contact fingers as usual. than one revolution during the extreme travel of the upper roll 1.

The middle roll 2 is arranged to move vertically in the space between the rolls 1 and and is shifted by an electric motor T. indicates this fact by showing the motorconnected by worm gearing 8 to a not 9 rotating" in a fixed bearing and meshing with an upright non-rotatable screw 10 carrying on its upper end a. platform 11. The middle roll is journaled in boXeswhich slide in vertical guides and the journals or projections on said boxes are engaged by the hookedends of lovers 12 suitably fulcrumed at 13 and carrying Weight 1' 1 which overbalaucesthe weight of the roll and rests upon the platform 11. The sketch, shows this mechanism in a merely illustrative mannenas far l'l'lOlQsQlElbOl'iltQ and suitable mechanismwouldbe used in actual practice. A second limit switch. 15

rotates in synchronism with the movement of the roll 2 up and down, said switch being similar in construction to the switch 6.

roll 2 to move downwardly. Vhen the platform is lowered, the weight follows it down a 16. The

and raises the roll 2. Whenever the motor runs the switch 15 turns also, making a little less than one revolution during the time that t-he'roll 2 is traveling through its greatest range-of movement. The two switches are electrically connected in such a manner that when they occu y a certain predetermined angular relation the motor circuit will be broken. This relation changes for each station to which the upper roll is ad justed.

Turning now to Fig. 1, the. positive and negative mains appear atX and Y, respec tively, controlled by a double-pole switch power circuits are shown by heavier lines than the control circuits, which receive current from the mains X Ythrough the switch 16. The motor 7 is'diagrammatically represented by the armature A, the commutating pole field coil F and the shunt field coil S, the latter being connected across the mains X Y by the conductors 17. The upper or screwdown limit switch 6' is shown in this figure below the other limit switch 15. Switch 6 has one continuous segment a and a plurality of short segments b, c, 03, etc. each overlapping the next so that alternate positions 2, 4, 6, etc., have two segments available. All the segments are cross-connected. Fingers a, b, 0, etc., cooperate with said segments.

Switch 15 has two continuous segments h, z, and a plurality of interrupted segments (2 0 d etc. The interruptions cover one position and are stepped in the opposite direction from the short segments on the screw-down switch. The ends of adjacent segments. overlap so that their ends occupy the alternate positions 2, 4, 6, etc. The continuous segment h is connected with all the right-hand portions of the interrupted seg .ments bf, (2", etc., and the continuous segment 2' 18 connected with all the left-hand portions of said segments. Fingers h, i cotive segments 1), 0 etc. The fingers which coiiperate with the stepped segments in the screw-down limit switch 6 are connected respectively with the fingers bearing the same reference letters which cooperate with the interrupted segments in the limit switch 15, but inversely; that is, the lowest finger in switch 6 with the highest finger in switch 15, and so on. Finger a of switch 6 is connected by the wire 18 with the main X through the switch 16, and by a branch wire 18 with afinger I in a masterswitch 19: Finger b in switch .15is connectedby wire 20 with another finger 7c in. said master switch, as well as to finger b 1n switch 6. Finger h is connected by a wire 21 witha solenoid 22 forming part of the up relay and finger i is connected by wire 23 with the solenoid 24 of the down relayr Both solenoids are connected by wire 25 with the negative main Y through the switch 16.

l The up relay has an interlock 26 which when down closes on twocontacts 27 and when raised on two contacts 28. In a similar manner the interlock 29 of the down relay closes on the sets of lower and upper contacts 30 31. Contacts 27 are connected respectively by wires 32 33 with the fingers n 0 in the master switch. One" of the contacts 28 is connected by wire 84 with the finger m in said switch. The other contact 28 tactors serve to close the circuit of the motor 7 on both sides of the same. The two pairs send current from the mains X Y through said motor in opposite directions so it will shift the roll 2 up or down asthe case m( be.

Current coming along the wire-35 tem the up relay passes through an interlock 41 controlled by the contactor 39, thence through the coils of the contactors 37, and

38 in parallel then to the wire 42 and thenegative control conductor 25. When these contactors close, power current flows from contactor 37 through the field coil F and armature 'A from left to right and thence through contactor 38 to the resistance coils 43 44 Sof which any desired number may be used and so on to the negative main Y. When the cont actors 37 38 pick up, they also close the interlocks 45 46 in abranch circuit 35 from .the wire 35 which includes the coil, of the contactor 47. The energizing of this coil short circuits the resistance coil 43 andcloses an' interlock 48v which controls a branch circuit through the coil of conw thefield coil F and armature A from righti is reversed.

ftactor-4 9. This shortcircuits the other resi'stlance.il'andputs the motor up to full speed. I lhe interlock l6 h 'asla high resist- 1 f iance holding coil, 50 in a shunt 51' around th'eres stanCeS 43 414:; "and the nterlock 48 'has a lowjres1stance holding 0011 52 in series .Ifwit-h the'power circuit ,Tlicse coils 5O 52 "pre'i'e'nttheir interlocks from closing until 1 the currentin thepower circuit has dropped toagiten value. A second interlock 5-4; is opened by"1theconta ctor 3'7 when it picks tun thereby opening; a control circuit which "branches from the control conductor- 18 through the wire 55, passes t-hrougl'i the interlocks on the contactors respectii ely, thence through the actuating 1 coil-' ot thefcontactor 57 and on out to the "negative conductor-25.; The contactor 57 shortcircuits part'of-a resistor 58 which is permanently connected across the terminals of the motor 7. it high resistance holding coilelluinishunt itossaid resistor retards the fcl'osing'otaninterlock (30 which controls a ccntacto-r til'whoseclosing short circuits the i "motor one. dead shortcircuit. The resistor '58 sfput; back 111 circuit when the ccntactor BT'p c'hsup and opens the interlock 5st in I? lthecontr'olcircuitfie. 1f the down. re-

.laj 'is the one'whichhas' closechthen current will flowwthroughthe wire 36 to the'1nter'- --l'ock 62 controlled by the contactor 3?, and

[l\fill' divide between the contactors 39 and l 1 40. "Whenthese pickup they close the interlocks G3 ((E-t controlling the, branch circuit,86""fromthe wire 86 which at the interlock 61- ccnnects with the circuit 35 and if jcutst'out' thelresistance coils M as before. The -motor will now be running at full-speed, That the current flows through to-left, so that the direction of the motor Having thus described the motor control and power circuits and the'conncction there- .with; of the up and down relays, I \\-ill"11ow;turn 'to the limit switches 6 15 r and" the master switch-19'. The up re- 'l ay, which causes the motor 7 to raise the middle roll connected .withthe right thei down relay being connected with the left hand portion thereof. During the re 'ticn to the other in succession, breaking cir cuit at the gaps-in the/segments. The button Z in the 'master switch isalways alive, and the button A: will become alive as soon as the fingers a 6 make contact with the segments a 7) of the screw-down switch. The operation can best be explained by taking an example or two. Assume that the middle roll 2 is resting on the lower roll 3 'i3 5 wi th the upper-r0111 atits-highest position,

remainder the resistor 58, and puts the handor lower portion of the switch 15:

tation of this switch by the motor 7, the. contact fingers it, etc. pass from one porthat is, somewhere in the region indicated by the'line 11-. A bill'et has been passed between rolls 1': and 2 and is ready to be p'assedback between 2 and In order to effect a reduction in the thickness of the billet,:the space between rolls 2 and 3 must be less-than that which now exists between rollsl, and 2, and yet roll 2 must be backed up by the upper, roll to give it rigidity. This-means that the upper roll must be lowered by an amount equal to the .desired reduction in thethickness of thebillet. Moreover, the motor attached to the platform 11 must lower it -tar enough to let the counterweight .L-l lift the roll into firm contact with the lowered upper roll but must stopv as soon as the platform has dropped slightly away from said counterweight. Assume that an attendant screws downthe upper roll. into the region indicated bythe dotted line 9. T This operation also rotates the switch Gj-until the tier of fingers. a, ,6, etc., register with the territo ry marked 9 in Fig. 1. -The finger a will be on segment a and theiingcr f on segmentf, all other fingers of this switch being out of contact with" their segments. The middle roll being in its lowest position, its switch 15 will stand in the position shown. Current will then fio-w from the switchlG by way of the wire 18 to the finger a, segment a, segment f, linger f, finger f -right-hand part of segment f segment h,,finger h, wire 21, relay coil 22", and wire to switch 16. The up relay will at once pick up, causing the interlock to bridge the contacts 28. An at tendantfnc-w shifts the master switch until segment 2) rests on buttons Z, m, and 0. This sends current from the switch 16 by way of wires 18', 18, button l,.segment 2), button m, wire 34, contacts 28, contacts 30, and wire 35 to the coils of the up contact-ore 37 38, starting the motor, as beforedescribed', to let the" roll rise. The closing of the switch 16 has placed the motor armature A and field coil F on a dead short circuit by cutting out the resistor 58. But thepicking up of the power cont-actor 37 breaks the control circuit at the-interlock. 54- and allows the contactors 57 (31 to open again, thus restoring the resistor 58 to the shunt around the armature and series field and forcing the power current to flow through said armature. and field.

As soon asthe motor commences town,

the counterweight 1st begins to lift the roll 2, and the motor also rotates the switch 15.

-lVhen the break, in the segment f arrives contactors 87 and 38 and cut ofl the power current. The circuit 55 is also reestablished, cutting out the resistor 58 which was in C11- vcuit while the meter was running, and Clos ing the motor armature on a short circuit, containing no resistance, so that, running by momentum, said motor acts as a generator and stops almost instantly, with the platform 11 a short distance below the counterweight 14. The billet is now passed through between the middle roll and the lower roll,

after which the middle roll must be brought down to its former position on the lower roll, and the upper roll must be lowered again to further reduce the space between it and the lowered middle roll to effect another reduction in the thickness of the billet.

A uick lowering of the middle roll can be e ected by throwing over the master switch 19 until the segment 1 rests on the buttons 70,1 and n. This sends current from the switch16 by way of the wires 18 18,

J button 1, segment 1*, button A, wire 20, finger platform 11 and lowering theroll 2 and also rotating the switch 15 backward until the first or lowest position is reaehechwhen the relay circuit is broken at the'finger b the down relay drops, and the motor stops as before with roll 2 resting on roll 3. The screw-down operator now screws down the upper roll to the desired new position; say somewhere in the territory of the station 8;

' the switch 6 turning to said position at the same time. Both relays are down and no current can flow to the motor until an attendant throws over the master switch to return segment 7) to its position on buttons Z, m and 0. Current then passes from the main X by way of the switch 16' to wire 18, finger a, segment a, segments 0- f, fingers e f, fingers e f and the right hand portions of segments 6 f segment h, finger h, and wire 21 to the up relay coil 22. Again the motor starts to let the roll 2 come up toward the eighth station, and the switch 15 turns with it. The finger a arrives at the break in segment etwhen it reaches the seventh position, but current continues to flow to the relay through finger f until the eighth position is reached. The finger c has now passed over upon the left hand portion of its segment 0 so that although the up relay is still energized through the segment f'-, yet current will flow from finger e to the segment 2', finger 2', wire 2?, and solenoid 24, so that the interlock 29 will be opened and will break the control circuit 35 at contacts 30 and stop the motor. Both relays are nowin their raisedpositions and yet the effect is the same as when both were down that is, the motor cannot run. The

middle roll is now shifted to its original po-' sition again by throwing over the master switch tobring the segment 1 into service. The relays are both raiscc, but the current by way of the button a will energize the down contactors as before. The down relay will drop when the switch 15, turning with the middle roll, arrives at position 1, and the finger 6 runs. ofi' its segment b The up relay still -remains energized through the fingers e, f, e 7. Now if the operator screws down roll 1 to a new position, the fingers e, f may slide off their segnients, but the circuit of the relay coil 22 will be maintained by other fingers closing von their segments before a f" open. \Vhen the upper. roll and the switch 6 arrive at the new position and the plate has made the upper pass, the operator of the master switch 19 merely throws it over to bring segment ;0 into service, which will send current through the up control circuit 35, and lift the middle roll to the position required for the lower pass. In this way, the upper roll can be gradually lowered, and after each upper pass of the plate the middle roll will lift just far enough to come into firm contact with the upper roll, ready for the lower pass. If the motor overruns at either end of its travel no harm will be done, owing to the loose contact of the platform 11 with the weight 14 at one end of the levers 12, and the similar connection of the open hooks at theother end of said levers with the journal boxes ot the middle roll.

In'casc the middle roll has been liftedand the screwdown operator proceeds to screw down the upper roll ant thereby push down the middle roll also, it IS desirable that the motor be started to cause the platform to. follow up the weight 14. Both relays are down. The limit switches stand at say position 9. hen switch 15 moves to the next position (8) finger (2 will make contact with its segment 6 and will send current-to finger.

a which is resting on the lefthand'iportion of the segment" 6 This Wlll cause the down relay to pick up and close the cirg cult from the button 0 in the master switch to the contacts 27 bridged by the interlock. 20, contacts 31, and the down control cir-. cuit 36. The roll 2 will therefore be dropped by the motor at-the same rate of speed that the upper roll is screwed down. If, on the other hand. the operator had screwed the upper roll upwardly while the middle roll was in contact with it, the up relay would have been energized again through segment 7, the connected fingers .{7 g and the segment so that the roll 2 would have followed up the upper roll.

3 tion of said motor,'a' relay controlling each In accordance with the provisions of the I patent statutes, I have, described the prin ciple of operation of my invention together with the apparatus which-I now consider to represent the best; embodiment thereof; but

I desire to have it understood that the apparatus shown is only illustrative, and that the invention can be carried out by other What I claim as new and desire to secure thereby, a limit switch moving synchro- ".nou'sly with saidv element, a second limit switch. controlled by an attendant, and a I master-switch cont-rolled by an attendant 2; The combination with an electric mo- 3 tor, of a movable machine element actuated thereby, contactors' controlling the power circuit,- of said motor, relays controlling said contactors, and ,two limit switches controlling said'relays, one limit switch being controlled by an attendant and the other moving synchronously with said moving element.

The combination with an electric motor, of a movable machine element actuated thereby, two or more contactors or sets of contactors controlling the direction of rota-,

' contactor or, set-thereof, and each relay controlling both control circuits, said circuits beingop'en when] both'relays are in either ,theirupper or lower positions, and limit switches controlling said relays.

1 4. The conibination with a three-high rolhng mill, of an electric motor for ralsing and lowering the middle roll, u d down contactors controlling the power circuit of said motor, up and down '.'relaysboth'controlling the two control cir- 9 middle roll, said lintit switches controlling said relays.

- cuits of said contactors, alimit switch moving with the vertical adjustment of the upperroll, and a limit" switch moving with the 5. ..The combination with .a three-high rolling mill, of an electric motor forv raising and lowering'the' middle roll, up and F down contactors controlling the ower c1r cu1t of said mot0r," up and own J relays bot-h controlling the two control cir- I cuits of'said contactors, a limit switch mova 7 upper roll, and a limit switch moving with ing with the vertical adjustment of the rolling mill, of an electric motor for raising and lowering the middle roll, means whereby the lift of saidroll is controlled by the position of the upper roll, and meansfo-r causing said middle roll, when lifted, to folloivl' the changes in position of said upper ro 8. The combination with an electric motor, of two relays controlling respectively its two directions of rotation, and two limit switches controlling said relays, said switches having a plurality .otfingersand cooperating segments, and said segments overlapping at their ends. so that a greater number of limit positions is afforded than the number of segments.

9. The combination with an electric motor of two controllers in circuit therewith, one having a plurality of stepped and overlappingsegments, and the other having a pluralityof interrupted segments, the interruptions being stepped.

10. The combination with an electric motor of two controllers in circuit therewith, one having a plurality of stepped and overlapping segments, and the other. having a plurality of interrupted segments, the interruptions being stepped, a group of fingers for each controller, and connections between corresponding fingers in said groups 11. The combination with an electric motor,'of a plurality of contactors for controlling the same, a'pair of relays each having an up and a down position for con-' trolling said contactors, and means whereby said motor circuit is opened when both relays are in either the up or the down position.

In witness'whereof, I have hereunto set my hand, this 18th day of August 1911.

ROBERT H. MoLAIN.

Witnesses:

' BENJAMIN B. HULL,

HELEN ORFORD.

copies of this patent may be obtained for five cents each, by dressing the commissioner of Patents,

y Washington, D. O."

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