US1844834A - Motor controlling apparatus - Google Patents

Description

Feb. 9, 1932. w, wYMAN 1,844,834

MOTOR CONTROLLING APPARATUS Filed Jan. 2, 1929 5 Sheets-Sheet 1 Au /4M awry.

Feb. 9, 1932. c. w. WYMAN MOTOR CONTROLLING APPARATUS 3 Sheets-Sheet 2 Filed Jan. 2, 1929 7 1522262392 /zariea' 5M Zq'yman.

Feb. 9, 1932. c. w. WYMAN MOTOR CONTROLLING APPARATUS Filed Jan. 2, 1929 15 Sheets-Sheet 3 Patented Feb. 9, 1932 UNITED STATES PATENT OFFICE CHARLES W. WYMAN, OF CLAREMONT, NEW HAMPSHIRE, ASSIGNOR TO SULLIVAN MACHINERY COMPANY, A CORPORATION OF MASSACHUSETTS MOTOR CONTROLLING APPARATUS Application filed January 2, 1929. Serial No. 329,929.

My invention relates to motor controlling apparatus.

The general object of my invention is to provide improved means for controll ng reversible motors. It is a primary ob ect to provide improved controllin apparatus for electric driving motors involving improved interlocking mechanism for a reverse sw tch, preventing reversal of the latter at times when such reversal would result in the breaking at the reverse switch contacts of circuits through which substantial currents are flowing. Particularly when automatically controlled starting resistance cutting out systems are employed is there a likelihood of the interrupting of large currents at the reverse switch contacts unless safety devices are provided, for should a contactor stick the reverse switch might be called upon to interrupt the full line current, which might result in short-circuiting the reverse switch and burning up of the latter. It is an object of my invention to provide improved means for preventing operation of the reverse switch under such conditions. It is a still further object of the invention to provide improved interlocking mechanism for the reverse switch controlled by an electro-magnet connected in such a mannerthat the regenerative current present due to the continued rotation of the motor cannot be broken at the reverse switch contacts. In an approved form the reverse switch lock magnet may be connected directly across the armature. A still further object of the invention is to provide an improved locking device for a common operating element for both a reverse switch and a pilot switch which controls automatic controlling apparatus located at a point remote from the reverse switch, this improved locking device operating, while currentflow in the motor continues, to prevent movement of thecontrolling element to a position effecting reversal of current in the motor while permitting sufiicient movement to efiect control of the pilot switch. Still another object of the invention is to provide improved means for preventing reversal of the motor while the latter is running at generating speeds.

Other objects and advantages of my inven tion will appear during the course of the following specification and claims.

In the accompanying drawings I have shown for purposes of illustration one form which my invention may assume in practice.

In these drawings,-

Fig. 1 represents a view generally in plan, the machine casing being broken away to show the illustrative embodimentof my improved reverse switch and controlling elements.

Fig. 2 is a central vertical section through the illustrative embodiment of my improved reverse switch and interlock, on line 22 of Fig. 1.

Fig. 3 is a transverse section through the machine casing on line 3-3 of Fig. 2, show ing the illustrative embodiment of my improved reverse switch interlock in elevation.

Figs. 4, 5 and 6 are diagrammatic views of the illustrative embodiment of the reverse switch and associated elements, the reverse switch being shown in its different positions.

Fig. 7 is a wiring diagram illustrating the illustrative embodiment of my improved reverse switch and interlock as connected to a controlling apparatus located at a point remote from the motor.

In a preferred form of my invention I have provided a reverse switch of rugged construction having an operating element which when moved in either direction from a neutral position automatically closes a pilot switch. This pilot switch closes a control circuit for automatic controlling apparatus located at a point remotefrom the motor, operating to place the motor across the line through resistance and gradually cut out the resistance. A movable plunger is arranged adjacent the common control element for the reverseswitch and pilot switch and is actuated by an electromagnet into interlocking relationship with the controlling element when said magnet is energized. This interlock while permitting a limited movement of the controlling element, sufficient to enable change in position of the pilot switch, prevents suflicient movement to separate the reverse switch contacts until the electromagnet is deenergized. The coil of this magnet r material such as bakelite or hard rubber.

is connected directly across the armature terminals so that the magnet is energized until the motor comes nearly to a standstill because of the voltagegenerated in the armature rotating in the self generated magnetic field. /V hen the motor comes to a standstill this interlock automatically releases, permitting the reverse switch to be moved to its opposite position for effecting reversal of the motor.

In the specific embodiment of my invention illustrated in the drawings I have shown a machine frame 8 in which may be mounted a control shaft 9 extending into the interior of the casing and having on its operating end outside the casing a manual controlling element 10. Reverse switch mechanism is at tached to the machine casing by means of a suitable bracket 11 and bolts 12. This bracket has a vertically projecting portion 13 which provides a recess 14 forming a housing for a part of the movable switch act-uatingelement '15. A bearing plug 16 fixed to the stationary bracket projects into a recess 16 in the movable member 15, and a spring 17 mounted between said plug and recess acts against the movable element 15 to hold the movable contacts of the reverse switch in engagement with the stationary contacts. This switch carrying element 15 may be constructed of any suitable insulating A pair of arcuate movable switch elements 18 and 19 of conducting material are loosely connected to member 15 by small lugs 20 and 21 projecting into recesses 22 and 23 respectively in member 15. The stationary contacts of the reverse switch are secured to a stationary plate 24 of insulating material by intermediate member29 which, together with stationary plate 24, forms a housing for the reverse switch. The plate 24 and member 29 are secured to the upstanding portion 13 of the bracket 11 by any suitable means such as bolts 46. A gear 30 is formed integral with the switch carrying member 15 and is adapt ed to mesh with a pinion 31 on the operating shaft 9. It is'of course not necessary to have the teeth in gear 30 extending completely around the periphery of the member15, since only a segment of the gear will ever be brought into mesh with the operating pinion.

In Fig. 1 particular attention is directed to the manner in which the operating handle 10 is mounted on the control shaft. A key 32' connects the handle to the shaft so as to prevent relative rotation but permit a limited amount of longitudinal sliding movement. On the exterior surface of the hub ofhandle 10 there are formed a plurality of grooves 33 and 34 connected by a longitudinal groove 35, and a stationary pin 36 suitably mounted on the frame of the machine engages in the grooves so as to prevent rotation beyond the central or neutral position without a pause to slide the handle longitudinallyot the shaft.

My improved interlocking mechanism for the reverse switch will now be described. As est shown in Figs. 2 and 3, the switchactuating element 15 has formed therein a pair of arcuate recesses 37 and 38 either of which is adapted to receive the end of a lockingplunger 39. An electromagnet having a coil 40 housed in a casing 41 is fixed directly to the bracket by means of a threaded stud A movable armature 43 is mounted on the casing 41 and directly connected toplunger 39by a nut 44.

A spring 45 normally holds the armature 43 and plunger in the retracted position, as shown in Fig. 2, where they will. not interfere with operationof the switch actuating member 15. However, when the coil 40 of the electromagnet is energized, the armature will be attracted and the end of plunger 39 will engage in recess 37 or 38, depending on the position of the reverse switch, and control the movement of the switch actuating element as will presently appear. For the purpose of preventing accidental displacement of the switch actuating element 15 from either-of its on positions, there is provided a small plunger 47 having a conical head adapted to engage in conical recesses in the switch actuatingelement and resiliently held in engagement with these recesses by a spring 48.

The switch for controlling the pilot circuit of the remote controlling apparatus as before stated is arranged to be actuated by the same operating element as the reverse switch and is herein shown in Fig. 3 at 49. Theterminals which connect to the pilot circuit are indicated at 50.and 51, the switch 49 being piv- .otally connected to one of these terminals and normally held open by spring 52. The lower side of switch 49 rests on the teeth of gear 30 and as indicated In dotted lines in Fig. 3, a

a number of these teeth are cut away to for an arcuate portion 53 of reduced radius which will permit control switch 49 to drop to open position when the reverse switch operating element is in neutral position or within a certain predetermined angle at either side of neutral position.

Attention is now directed to the diagrams shown in Figs. 4, 5, and 6. Fig. 4 shows the reverse switch in neutral position. A pair of stationary contacts 54 and 55 diagonally opposite each other connect to power lines 56 and 57 respectively. The other pair'of stat onary contacts 58 and 59, also arranged diagonally opposite each other and midway between contacts 54 and 55, connect to the armature by means of wires 60 and 61 respectively, the armature being indicatedat 62.

In Fig; 4 the movable contacts 18 and 19 engage only the pair of contacts 54 and 55 connected to the power lines and therefore the tion. The movable switch elements 18 and 19 are touching only the pair of stationarv contacts connected to the power lines and the pilot switch 49 is in open position, resting on the cutaway portion 53 of the gear 30. The operator now manipulates the control handle in one direction or the other, depending on the direction of motor rotation which he desires, and the stationary pin 36 engages in groove 33 or 34. Assume that the operating element is turned so as to bring the movable contacts in the position shown in Fig. 5. The control circuit switch 49 has moved to closed position due to engagement with full length teeth on gear 30, and recess 37 is in positionpermitting engagement with plunger 39. During opposite direction of motor rotation the plates 18 and 19 are in the positions indicated in Fig. 6 and plunger 39 engages in recess 38. The pilot switch 49 is automatically closed on turning the reverse switch member in either direction to effect either direction of motor rotation. Now if the operator attempts to move the switch from the position of Fig. 5 to the position of Fig. 6 or vice versa, the length of recesses 37, 38 is such as to permit only a limited movement sufiicient to cause opening of the control switch but not sufiicient to break the main circuit, until the plunger 39 is retracted by its spring 45.

Referring now to thewiring diagram of Fig. 7, the units located at the machine are illustrated in the left hand portion of the figure and all the equipment in the right hand part of the figure may be located at any convenient remote point as in the entry of a mine and connected to the units on the machine by only three wires, as ina cable 85. This automatic remote control system is described in detail in my copending application Serial No. 243,964. filed Dec. 31, 1927, and will be herein described as briefly as possible, and if a more detailed description is desired, reference may be had to the aforesaid application. The motor in this figure is indicated at 62 and it will be noted that coil of the electromagnet is connected directly across the armature terminals by a pair of wires 63 and 64. The series field is indicated at 65 and the shunt field at 66, the reverse switch being indicated diagrammatically at 67 and the pilot switch at 49. The equipment included in the automatic controlling apparatus located at a point remote from the machine includes a plurality of resistance controlling contactors 68, 69, 70, and 71 and also a plurality of contactor controlling relays 72, 73, and 74. The resistance unit controlled by the contactors comprises in this instance three sections 75, 76, 77. An overload switch 78 is adapted open the control circuit whenever there is an overload on the motor. In operation, the coil. of relay 72 is immediately energized when the reverse switch is turned suiiiciently to close a circuit, but not far enough to close the pilot switch, by power from the minus side of the line through reverse sw ch 67, meter 62, series field 65, line 79, through all the resistance units, lines 80, 81 and hack to the positive side of the line through lines 82, 83, 84. Upon closure of pilot switch 49, the holding coil for the first contactor 63 is energized by power from the minus side of the line through switch 49, pilot wire and line 86 and back to the positive side of the line through lines 87, 88, 89, 90. Closing of the first contactor 68 shortcircuits the coil or relay 72, allowing the same to close a circuit after a certain interval of time required for the current to die out in relay 72, and power flows from pilot wire 85 through wire 91, relay 72, line and energizes the coil of relay 69, the cir' t being completed to the positive side of the li .e through wires 93, 88, 89, and 90. At the time of closing of the first contactor 68, the holding coil for relay 73 was energized by the voltage drop across section 77 of the resistance through lines 94, 95 and 80. When the second contactor 69 closes, the first p on of the resistance is cut out and at the same time the holding coil for relay 7 is short circuited, thereby allowing the same to close after a certain time interval required for the current to die out in the relay coil. In a similar manner contactors 70 and 71 are closed in turn and the motor placed directly on the line by the last contactor 71. At the time of closing of this contactor a switch 96 in the control circuit is opened, thereby deenern ing the holding coils for the first three c actors. However, the last contactor is kept energized by power from the pilot wire through relays 7 2 and 74.

In my copending application Ser. No. 243,964 above referred to, I are presenting claims to an electric motor contl system including a motor, main power lines leading thereto, an adjustable resistance, and apparatus for connecting the motor to the power lines through the resistance and for gradually cutting out the resistance the motor comes up to speed, which apparatus comprises a plurality of switches, and electromagnetic means for operating them in a predetermined sequencc, a control circuit for supplying current to the elcctro-magnetic means, and mechanical means for automatically breaking the circuit through all the electromagnetic means except the one for operating the last switchwhen the last switch element, due to the lost motion connection between the interlock and swltch actuating element. The electromagnet of the interlocking mechanism will be supplied with suflicient energy to hold this armature retracted until the speed of the motor has been reduced to such an extent that the voltage across the armature is practically zero.

Should a contactor stick, when an attempt was being made to effect reversal of the motor, the lock plunger would not be withdrawn, because the line current flowing would flow in part through the 001i 40 and prevent movement of the reverse switch to reverse position. If the motor is not running at a sufficient speed so that the counter electro-motive force would hold the lock in, no detriment would result from reversing.

While I have in thisapplication specifically described one form which the invention may assume in practice, it will be understood that this-form is shown for purposes of illustration and that the invention may be moditied and embodied in various other forms without departing from its spirit or the scope of the appended claims. 7

W hat I claim as new'and desire to secure by Letters Patent is:

1. In combination, a motor, a controlling device therefor, reversing mechanism for controlling direction of rotation of said m0- tor, means operated on-movement of said reversing mechanism for controlling sald controlling device, and means for preventing movement of said reversing mechanism sufiicient'to efiect reversal of said motor until the motor has come substantially to a standstill'but permitting enough movement to effect control of said controlling device.

2. In combination, an electric motor, controlling apparatus therefor, a reverse switch for controlling directionof rotation of said motor, means operated directly by movement of said reverse switch for controlling said controlling apparatus, and means for preventing movement of said reverse switch sufficient to reverse current flow in said motor while the motor is rotating but'permitting enough movement to effect control of's aid controlling apparatus.

3. In combination, an electric motor, controlling means therefor, a reverse switch for controlling direction of rotation ofsaid mo tor, means operated on movement of said reverse switch for controlling said controlling means, and a positivelocking device for preventing movement of said reverse switch to a position effecting reversal of current flow in said motor while the motor is rotating at a substantial speed but permitting movement to eifect control of said controlling means whereby the voltage which may be applied to the motor on reversal is materially reduced.

4. In combination, an electric motor, automatic controlling apparatus therefor, a reverse switch for controlling direction of rotation of said motor,'a control switch operated on movement of said reverse switch in either direction from a neutral position for controlling said controlling apparatus, and means for preventing movement of said reverse switch. to a position effecting reversal of current flow in'said motor while'th'e motor is rotating above a certain speed but permitting enough movement to effect 'operation of said control switch.

5. In combination,a source'of power, a resistance, an electric motor, controlling apparatus for said motor for connecting the same to the source of power and for interrupting power supply including means for connecting the motor to the source of power through the resistance and automatically gradually cutting out said resistance, a reverse switch for controlling direction of rotation of said motor, a control circuit for controlling said controlling apparatus provided with a pilot switch, means automatically operating said pilot switch on predetermined movement of said reverse switch, and means for preventing movement of said reverse switch to a position effecting reversal of current in said motor while the motor is rotating at a predetermined speed but permitting movement of the reverse switch to efiect control of said pilot switch and controlling apparatus.

6. In combination, an electric motor, automatic controlling apparatus therefor, a reverse switch for controlling direction of rotation of said motor,.a pilot circuit controlling said controlling apparatus, a pilot switch in said circuit automatically operated on V movement of-said reverse switch from neutral 'posltlon to eitherof its on positions for setbreak the connections established thereby while the motor has motion above a predetermined speed, and means for energizing said electromagnetic means directly across the armature terminals of said motor.

8. In an electric motor controlling apparatus, a motor, a manually operable reverse switch lei efi'ecting reversal oi said motor, a mechanical interlocking mechanism for preventing movement of said reverse switch from one direction controlling position to another or to break the circuit therethrough but permitting a limited movement of said reverse switch, electromagnetic means for actuating said interlocking mechanism to interlocking position when energized, and a circuit connected directly across the armature terminals for energiang said electromagnetic means.

9. In an electric motor system, a source of power, a resistance, a motor, controlling apparatus for connecting the same to the source of power and for interrupting power supply including means for connecting said motor across the line through the resistance and automatically gradually cutting out said resistance, a pilot circuit for setting said automatic apparatus into operation provided with a pilot switch, a manually operable reverse switch for controlling said pilot switch and direction of rotation of said motor, interlocking mechanism allowing movement of the reverse switch to effect control of said pilot switch but preventing movement from one direction controlling position to the other while the motor is rotating at a substantial speed, an elcctromagnet for rendering said interlocking mechanism effective when energized, and a circuit for energizing said electromagnet by current flow through said armature.

10. In combination, an electric motor, controlling apparatus therefor, a pilot switch for controlling said controlling apparatus, reverse switch means for controlling direction of rotation of said motor, a common operating element for said pilot switch and said reverse switch means, and interlocking mechanism for preventing movement of said operating element to a position effecting reversal of current flow in said motor while the motor is rotating at a substantial speed but permitting movement to efiect operation of said pilot switch.

11. The combination specified in claim 10 wherein said interlocking mechanism comprises a plurality of elongated recesses in said element, a plunger adapted to engage in either of said recesses to permit only a limited movement of said operating element, and an electromagnet for actuating said plunger to interlocking position energized by voltage across the armature terminals.

12. In combination, an electric motor, controlling apparatus therefor, a pilot circuit for said controlling apparatus, a pilot switch in said circuit, reverse switch means for controlling direction of rotation of said motor, a common operating element for said pilot switch and said reverse switch means, interlocking mechanism for permitting movement of said operating element suliicient to control said pilot switch but preventing suflicient i'novcmen to reverse current flow in the motor vhile rotating at a substantial speed, electromagnetic means for operating said interlocking mechanism to eiiectiveposition, and means for controlling said electromagnetic means in response to voltage generated in the armature during rotation.

13. In an electric motor controlling apparatus, a reversible motor, a manually operable reverse switch, electromagnetic interlocking means for preventing movement of the reverse switch from one direction controlling position to the other while the motor has motion above a predetermined speed, means for energizing said electromagnetic means by voltage across the armature terminals during motor rotation, and means for preventing immediate reversing by said reverse switch after release of said interlocking means.

14. In combination, a reversible electric motor, controlling apparatus therefor, a pilot switch for controlling said controlling apparatus, a reverse switch for controlling direction of rotation of said motor, common operating means for said pilot switch and reverse switch, interlocking mechanism for preventing operation of said reverse switch irom one direction controllin position to the other while permitting operation of said pilot switch while the motor has motion above a predetermined speed, electromagnetic means for controlling said interlocking mechanism in response to voltage across the armature terminals, and mechanical means cooperating with said common operating means for preventing uninterrupted movement of said reverse switch at'ter release of said interlocking mechanism.

15. In combination, an electric motor, controlling apparatus theret'or, a pilot switch for controlling said controlling apparatus, reverse switch means for controlling direction of rotation of said motor including relatively movable contacts, a. common operating element for said pilot switch and said reverse switch means operable to operate said pilot switch only subsequent to movement of said reverse switch to a circuit establishing position, and interlocking mechanism for preventing movement of said operating element to effect breaking of a circuit at the reverse switch contacts while the motor is rotating at a substantial speed but permitting movement or" said operating element to effect restoration of said pilot switch to its initial position.

16. A motor, lines for supplying current thereto, a switch movable to eiiect a predetermined relation. between the terminals of the motor to prepare the same for rotation in a predetermined direction on line current supply thereto, a switch movable to establish and to'interrupt flow of line current to said motor,- means movable to operate said first mentioned switch and thereafter said second mentioned switch and reversely movable to effect their opening in reverse order, and means for preventing reverse movement of said first mentioned means to effect opening of said first mentioned switch while said motor is'rotating above a predetermined speed but permitting movement thereof'to etl ect opening of said second mentioned switch.

17. In combination, a motor, a switch closed to effect motor operation and opened to stop the motor, a reversing switch, and common operating means for said switches having a neutral position and movable in opposite directions therefrom and operative on predetermined movements in opposite directions from said neutral position to move said reversing switch to its positions for establishing circuits to efiect operation of saidmotor in opposite directions and on further predetermined movements from said. neutral position in either direction to effect closure of said'first mentioned switch, and means for controlling movements of said operating means towards neutral position preventing movement of said reversing switch to break circuits established by its movement from neutral position while said motor is rotating at a rate above a predetermined speed.

18'. In' combination, a motor, a switch closedto efiectmotor operation and opened to stop the motor, a reversing switch, and com mon operating means for said switches having a neutral position and movable in opposite directions therefrom and operative on predetermined movements in opposite directions from said neutral position to move said reversing switch to its positions for establishing circuits to effect operation of said motor in opposite directions and on further predetermined movements from said neutral position in either direction to effect closure of said first mentioned switch, and means for controlling movements of said operating means towards neutral position preventing movement of said reversing switch to break circuits established by its movement from neutral position while said motor is rotating at a rate above a predetermined speed including electro-magnetically controlied locking means supplied with current whenever the motor is rotating above a predetermined speed.

In testimony whereof I afiix my signature.

CHARLES W. WYMAN.

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