US2050232A - Time delay relay and control system employing the same - Google Patents

Description

Aug. 4, 1936. H, VAN VALKENBURG 2,050,232

TIME DELAY RELAY AND CONTROL SYSTEM EMPLQYING THE SAME Filed Feb. '7, 1955 2 Sheets-Sheet l INVENTOR. Herman 1. Km lrlimlwg,

E JW

ATTORNEY.

Aug. 4, 1936. H. L..VAN VALKENBURG 0,

TIME DELAY RELAY AND CONTROL SYSTEM EMPLOYING THE SAME Filed Feb. '7, 1935 2 Sheets-Sheet 2 INVENTOR. Her/W021 Z. Vawkalieiiwy lax W A TTORNEY.

Patented Aug.- 4,- 1936 NITED STATES-- Tim: DELAY Remy AND ooirrnor. srs'rm: 'emnomo rm:

SAME

Hermon L. Van Valkenburz', Wauwatosa, Wis assignor to Square D Company, Detroit, Mich. a corporation of Michian Application February 1935; Serial No. 5,379

21 Claims. (01. 115-294) This invention relates to a time delay relay and more particularly'to'a relay automatically operable to give delayed low votage protection,

and to control systems employing the same.

In the operation of power systems supplying an electrical translating, device such as an electric motor through a controller or contactor, .it irequently happens that service may be interrupted for a very short interval or that'the line voltage may fluctuate temporarily. This, unless some' time delay mean is incorporated into the control system for the-translating device, will permit the contactors or controllers to open the motor circuit .and their holding circuits as well, thus permanently disconnecting the motor or other device from the line and necessitating the use of a start switch after each such disconnection to re-conmeet the device to the line for operation. Where the fluctuation or interruption in service is momentary or exists for a very short interval it is desirable that the motor be automatically reconnected to the line for operation when the voltage is again established.

While some systems in the past have employed delay devices, these have had many disadvantages inasmuch asthey-"have required modification of the oontactor or control station or both. Particularly where a delay device-has been incorporated into the control station a disadvantageous feature results as it is often desirable to provide a pluralityoi control stations, thus causing duplication of the delay equipment.

One object of the present invention is to provide a relay giving delayed low voltage protection which is adapted for connection to a standard controller and any number of standard push button control stations.

Another object of this invention is to provide a low voltage time delay relay which while automatically operating with a definite time period on reduction or failure of. voltage. may be immediately operated by the opening of a standard push button stop switch.

Another object of this invention is to provide a relay operating with a definite time interval in response to a circuit condition with means to render the delay means ineiiective to provide for immediate operation of the relay.

Another object of this invention is to provide a relay having a time delay element which may be selectively rendered eiiective or inefiective to delay the opening of the contacts.

.- Another object of this invention is to provide upon failure oi voltage.

opening of a switch and operating alter. a definite time period in'response'to voltage failure.

Another object of this" invention is. to provide a control system for an electrical translating device having a main contactor and a holding switch therefor with means to immediately open said holding switch in response to depression ota push button-stop switch and with means toiopen said holding after a definite time interval-upon failure .orreductionin voltage.

Another object of this invention isto provide a low voltage time delay relay and a control system for an electrical translating device employing the same in which the relay has only electrical connection to thecontactor and control station and is adapted to be included. in a standard control system employing any number oi'control. stations without change either in the standard contactor or the standard control station and inwhieh the relay operates immediately upon depression of a stop button and operates-with a time delay Further objects and features of this invention will be readily apparentto those skiliedin the art from the following specification andthe O appended drawingsillustrating certain'preierred embodiments 0! this invention in which:

Figure 1 is a front elevational view or a relay according to present invention.

Figure 2 is a side elevational view of the relay shown in Figure 1 taken from the right.

Figure 3 is a side elevational view of the relay shown in Figure 1 taken from the leit, with portions of the supporting bracket broken away to more clearly show the operating parts.

Figure 4- is a sectional view taken on the line IV-IV of Figure l.

FigureSisaviewsiniila-rtoFigureibutwith the parts shown in energized position.

Figure 6 is a diagrammatic view of the control system according'to present invention, showing the relay connected in a standard control system.

Upon a base i of insulating material are rigidly supported a pair of actuating coils 1, 3 having magnet frames 4, 5 and movable armatures 6 5 and 1. The ends of the coils are led to connectors 8 to which the control wires are secured. At the end oi armature 6 is pivotally mounted a generally U-shaped member 8 having legs ii and i2, this member being eccentrically mounted on its pivot it so that the legs H and 12 will tend to swing forwardly by gravity. To increase this forward bias on member 9, a leg t spring it may be provided, bearing on the back of leg H. 'A U-shaped supporting bracket [5 is rigidly secured 55 to base I with its legs on either side of armature G and is provided with vertical slots serving as guides for the ends of pivot it to guide the movement of the armature 6. At the bottom of the base i on either side of the path of movement oi. member 9 are stationary contacts [6, l6 which are bridged by a plate I! having contact faces l8, l8 at its ends cooperating with the stationary contacts l6, IS. The bracket i5 is provided with legs l9 adjacent its lower end and to these legs I! is pivoted a contact arm 2| to which the plate i1 is secured. A spring 22 inter-connects the arm 2| and the member 9 and tends to move them toward each other as is more particularly shown in Figure 4. When the armature 6 is in its released position the bottom of leg H strikes the contact carrier and moves it to open position. When the armature 6 is moved into energized position the spring 22 pulls the contacts into en- 'gagement and becomes extended, thus exerting considerable contact pressure as is more clearly shown in Figure 5.

A bracket 23 is secured to the base I and within this bracket and the remote leg of bracket l5 a ratchet cylinder 24 is rotatably supported. This cylinder is located along side the normal path of movement of the leg l2 and this leg is equipped with cooperating teeth 25 adjacent its lower end for cooperation with ratchet cylinder 24. It is noted that the teeth on the ratchet cylinder and on the leg I 2 are shaped to readily slide past each other in the upward movement of armature 6 and cooperating member 9.

A large toothed wheel 26 is rigidly secured to the end of cylinder 24 adjacent to the bracket 23. A shaft 21 is rigidly secured to bracket 23 and upon this shaft is pivotally mounted a member 28 having teeth adjacent its top and bottom adapted to alternately engage the teeth in the wheel 26 and to be oscillated thereby to permit rotation of the wheel. To the upper end of the member 28 is rigidly secured a stud 29 having a weight 3| threaded thereon. The construction last described is readily seen to afford a timing mechanism controlling the speed of rotation of wheel 26 and ratchet cylinder 24. The speed of oscillation of member 28 and consequently the speed of rotation of member 26 can be regulated by turning the weight 3| so as to change the moment arm of the weight about the pivot 21.

It is obvious that while one timing mechanism has been specifically described, various other time delay means can be readily substituted therefor within the spirit of the invention as examples of which are air and oil dash pots or any other equivalent time delay means.

A bell crank lever 32 is pivotally supported as at 33 upon legs 34 on the bracket i5. One end of this bell crank is secured to the lower end of armature I as by pivot 35. A stationary bracket 36 is provided to limit the opening of armature I. To the opposite end of bell crank 32 is pivotally mounted an L-shaped member 31 as by pivot 38 having the leg 33 of the L extending through opposite slots 4| in the opposite legs of bracket 15. The leg 39 extends across the space between the legs. of bracket l5 within the slots 4| and over the leg II on member 9. When armature 1 is moved upwardly to energized position the member 31 will be moved toward the base I through the bell crank 32, and leg 39 on member 31 will move leg I i also toward the base as is more particularly shown in Figure 5 of the drawing. Movement of the leg ll toward the base obviously moves leg l2 in the same direction and dis-engages teeth 25 from ratchet cylinder 24 in the position shown in Figure 5 which is the normal energized operating position of the relay. With the parts in this position it is readily seen that should the circuit through coil 2 alone be 5 broken armature 6 and its associated parts will be free to slide downwardly under the influence of gravity and the end of leg II will strike the contact carrier and separate the contacts without delay. Should, however, both coils be deenergized at the same time the leg 39 will no longer hold the teeth on leg l2 out of engagement with the ratchet cylinder and member 9 will be swung outwardly under the combined actions of gravity, spring l4, and the moment of spring 22 about the pivot 13. With the teeth 25 on leg i 2 engaged with ratchet cylinder 24, the downward movement of armature 6 will be under the control of the timing elements until the end of teeth 25 is reached. This ending should occur at least 20 by the time that the end of leg ll strikes the contact carrier so that the moving parts will, at that time, have no resistance to their movement other than that oiTered by the contacts.

It is noticed that spring 22 inter-connecting as 25 it does member 3 and the contact carrier exerts considerable contact pressure when the relay is energized and tends to pull the armature 8 and member 9 toward their released position when de-energized, against the resistance of the timing mechanism. Furthermore, as the member 9 opens the contacts it has no opposing force as would be the case if the bias on the contacts were to a stationary part. These features obviously contribute to more positive action 01 the operat- 35 ing parts.

It can readily be seen from an inspection of the drawings that armature I has only a small movement compared with armature 8 to release the leg II from its restraining position adjacent the base. However, due to the inertia of the parts, it is desired to have the opening movement of armature I proceed faster than that of armature 6 so that teeth 25 will engage ratchet cylinder 24 at the earliest point in the movement of armature 6. To secure this accelerated movement of armature I, a heavy spring 42 inter-connects the bell crank with a stationary part.

The operation of the relay should be readily apparent from the foregoing description. when the coils are energized the armatures will be pulled upwardly and contacts I6, l6 and l8, l8 will be closed under the bias of spring 22. Armature I will cause inward movement oi! leg 39 and hold teeth 25 out of engagement with ratchet cylinder 24 in the position shown in Figure 5. If coil 2 is now de-energized, armature 6 and its associated movable parts will quickly drop to re leased position and separate the contacts. If, however, when the parts are in energized position 60 both coils become de-energized,-the leg 39 will move outwardly permitting element 9 to move outwardly on its pivot l3, thus engaging teeth 25 with ratchet cylinder 24. The downward movement of armature 6 and its associated parts will then be under the control of the timing mechanism which causes a definite time period to elapse between de-energization and opening of the contacts.

The incorporation of this relay into a standard control system is diagramatically illustrated in Figure 6 in which a main contactor 5| having an operating coil 52 connects a motor or other electrical translating device 53 to line terminals 54. A plurality of remote control stations, each embodying a normally open start switch and a normally closed stop switch 55 and 56, are provided, these being connected to operating coil 52 in a manner conventional inthe art. Paralleling the start switches is the conventional. holding switch 52 mechanically movable by the movement of the main contactor. The relay is electrically connected in the circuit with its contacts in parallel with holding switchil, thus forming in effect a secondary holding switch. Coil 2 is connected in parallel with-operating coil 52 and coil {is connected across the line through the holding and start switches.

With the connections as above described,- it is seen that momentary closure of a start switch will energize coils 2 and 3 as well as coil 52 and will close the contactor and the contacts l6 and II on the relay. If one of the stop Switches is momentarily opened, the circuit through polls 2 and 52 is broken whereupon the contactor drops out and contacts l6 and I! are immediately opened. When, however, there is a failure or reduction in voltage, both coils, 2 and 3, become deenergized at the same time and the armature. 6

descends under the influence of the timing mechanism and a definite time interval will elapse before contacts l6 and I! are opened to breali:

the holding circuit. If the voltage is re-established before these contacts are opened, it is readily seen that the voltage across coils 2, 3 and I2 is again established whereupon-the main contactor will re-close and the armatures 6 and I be again drawn up into energized position. When,

however, the voltage is not re-established within the time interval elapsing before contacts l6 and H are separated, the holding circuit will be broken and a re-establishment of the voltage at any time thereafter will not re-connect the motor to the line.

With the control system as here described, it is not be necessary to remove it since it performs only an additive function.

While certain preferred embodiments of the invention have been specifically disclosed, it is understood that they invention. is not limited thereto as many variations will be readily appar- A momentary closure of said normally open switch,

said relay including means for immediately opening said contacts upon momentary opening of said normally closed switch and means for opening said contacts after a definite time interval upon reduction in voltage. I 2. In a control system for an electrical trans- 'lating device, a control station, normally open and normally closed switches at said station, a relay, contacts directly actuated thereby, said contacts being in parallel with said normally open switch, means energizing said relay to close said contacts upon momentary closure of said normally open switch, said relay including means for immediately opening said contacts upon momentary opening of said normally closed switch and means for'opening said contacts after a definite time interval upon reduction in voltage. 5 3. In a motor control system, a main contactor, a holding circuit for said main contactor, a relay controlling said holding circuit, a control station having stop and start switches, said relay closing said holding circuit upon momentary closing of 10 said start switch, said relay opening said holding circuit without delay upon opening of said stop switch, and means for delaying for a definite time interval the opening of said'holding circuit by said relay upon voltage failure.

4. In a control system for an electrical translating device, a main contactor, electromagnetic means for actuating said contactor, a push but ton control station including manually operable start and stop? switches, a holding switch in 20 parallel with said "start switch, and electromagnetic means for closing said holding switch upon closing of said start" switch, said last mentioned electromagnetic means immediately opening said holding .switch upon opening of said 25 stop switch and opening'said holding switch after a, predetermined time interval in response to a reduction in voltage.

5. In a control system for an electrical translatingdevice,a'contactor including an actuating 30 coil,' a remote control station including start and stop push button switches, a relay having only'electrical connection to said contactor and control station, said relay including a holding switch for said actuating coil, said relay 0105- 35 ing said holding switch upon momentary closure of said start switch and immediately opening said holding switch upon momentary opening of said stop switch, and means for delaying the operation of said relay to effect opening of said holding switch after a definite time interval in response to a reduction in voltage.

6. A low voltage time delay relay adapted for insertion in a standard push button motor control system including a contactor having a holding switch movable therewith and a remote'control station including push button start and stop" switches, said relay having contacts paralleling said holding switch, means closing said contacts upon closing of said. start" switch, means opening said contacts without delay upon opening of said stop switch, and means opening said contacts after a definite time interval upon failure orreduction in voltage whereby reestablishment of the voltage during said time interval will automatically re -close the contactor.

7. In a control circuit, a relay including cooperating contacts and a pair of actuating coils, an operating circuit supplying said coils, a normally closedswitch in series with one of said coils, said relay including means opening said contacts without delay when said switch is opened and meansopening said contacts after a predetermined time' interval upon reduction of the voltage of said circuit.

8. Ina controlsystem for an electrical translating device, a contactor including an actuating coil, a relay including a holding switch for said actuating coil and time delay means for delaying opening of 'saidholding switch in response to a .,dip in circuit voltage, and a plurality of remote control stations, each of said stations including a normally open start switch and a normally closed stop" switch, opening of any one of said 75 iii stop switches causing opening of said holding switch without delay.

9. In a control system ior an electrical translating device, a contactor including an actuating coil, a relay including a holding switch for said actuating coil and time delay means tor delaying opening of said holding switch in response to a dip in circuit voltage, a plurality oi remote control stations, each of said stations including a normally open start switch and a normally closed stop switch, means ior opening said holding switch without delay upon the opening of any one of said stop switches, and means for closing said holding switch upon the closing of any one of said start switches.

10. In a relay, separable contacts, a pair of operating coils, means for closing said contacts when said coils are energized, means for opening said contacts without delay when one oi. said coils is de-energized, and means for opening said contacts after a definite time interval when both of said coils are de-energized.

11. In a low voltage time delay relay, a pair of magnet coils, cooperating contacts, means controlled by said coils for actuating said contacts, said means opening said contacts immediately upon de-energization of one of said coils and opening said contacts after a definite time period upon de-energization of both of said coils.

12. A relay comprising cooperating contacts, an actuating coil having an armature movable to open and close said contacts, time delay remotely controlled means, and means for selectively interconnecting said armature and time delay means.

13. A relay comprising cooperating contacts, electromagnetically operated means for open ing and closing said contacts, time delay means, and electromagnetic means for selectively interconnecting said means to provide for delayed or immediate actuation of said contacts.

14. A relay comprising stationary and movable contacts, an armature, a coil Ior actuating said armature, said movable contact being biased toward closed position when said coil is energized, said armature in released position separating said contacts, time delay means, and electromagnetic means for selectively connecting said time delay means to said armature upon movement thereof to released position.

15. A relay comprising cooperating contacts, an actuating coil having an armature movable to open and close said contacts, time delay means, an element movable with said armature normally engageable with said time delay means, and electromagnetic means for holding said element out of engagement with said means for non-delayed movement of said armature.

16. In a relay, relatively movable contacts,

electromagnetic means for actuating said contacts, means for delaying action 01! said electromagnetic means in one direction, and a second electromagnetic means for rendering said delay means ineffective.

17. In a relay, separable contacts, an armature separating said contacts in released position, an operating coil therefor, means for delaying movement 01 said armature to released position, and electromagnetic means for renderlng said delay means ineffective to provide for free movement of said armature to released position.

18. A low voltage time delay relay including stationary and movable contacts, a pair of actuating coils, armatures ior said coils, one of said armatures separating said contacts when in released position, time delay means, means interconnecting said one armature and said delay means when the second armature is released, and means freeing said one armature from said delay means when said second armature is in energized position.

19. A relay comprising stationary and movable contacts, an armature separating said contacts in released position, an actuating coil therefor, time delay means, means movable with said armature for connecting it to said time delay means for delayed movement to said released position, a second armature, a second actuating coil, and means rendering said delay means ineffective when said second coil is energized, whereby said contacts may be opened without delay when the first coil is deenergized and whereby the contacts will be opened after a definite time interval when both coils are deenergized.

20. A relay comprising separable contacts, a pair of operating coils, armatures controlled thereby, one of said armatures opening the contacts in released position, means delaying movement of said one armature to released position when the second armature is released, and means providing for free movement of said one armature to released position while said second armature is energized.

21. In a relay, stationary and movable contacts, an armature, means biasing said movable contact toward said armature, a striker on said armature engaging the movable contact to open it when said armature moves toward released position, time delay means, means connecting said delay means to said armature, a second armature, and means controlled thereby rendering said connecting means selectively ineffective to provide for free movement of said first armature to released position to open said contact without delay.

HERMON L. VAN VAIKENBURG.

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