US3577034A - Power interruption control system - Google Patents

Abstract

Where a plurality of processing operations are powered from a common electrical supply, shutdown of the operations by momentary interruptions of power is prevented by timing a main circuit relay not to open unless the interruption has a preselected time duration, shorting individual switches that have opened due to the interruptions, and breaking such shorts soon after the power has resumed.

Description

United States Patent George D. Bernhard Lincoln Park;

Olek Schwarz, Plainfield, NJ. 861,882

Sept. 29, 1969 May 4, 1971 Anaconda Wire and Cable Company lnventors Appl. No. Filed Patented Assigne'e POWER lNTERRUPT ION CONTROL SYSTEM 4 Claims, 3 Drawing Figs.

Int. Cl 1101b 47/18 Field of Search 317/22, 36

[56] References Cited UNITED STATES PATENTS 2,934,701 4/1960 Weisberg et al. 317/141X 3,350,581 10/1967 Stein 3l7/141X 3,366,848 1/ 1968 Luehring et al..' 3 l7/22X Primary ExaminerJames D. Trammell Attorney-Victor F. Volk ABSTRACT: Where a plurality of processing operations are powered from a common electrical supply, shutdown of the operations by momentary interruptions of power is prevented by timing a main circuit relay not to open unless the interruption has a preselected time duration, shorting individual switches that have opened due to the interruptions, and breaking such shorts soon after the power has resumed.

PMENiTE unn 4m: 3577.034

- INVENTORS.

v I VGEORGE BERNHARD OLEK SCHWARZ Mill 1 POWER INTERRUPT ION CONTROL SYSTEM BACKGROUND OF THE INVENTION vln certain processing operations, particularly operations involving the continuous processing of an advancing strand, interruptions ofpower present a serious problem because, if the operation is merely resumed, without inspecting the condition of strand, after a lengthy interruption, portions of the strand will be damaged due to excessive exposure to processing conditions and to the sagging of the strand upon the slowing down of takeup devices. In many processes it is necessary to maintain a controlled strand tension, and if the takeup devices are started with slack strands these devices will overspeed and cause the strand to snap when the slack has been taken up. For this reason it has been the practice to have a manual control of the startup of each suboperation in a strand processing plant after a power shutdown. We have found, however, that the great majority of power interruptions are so short, less than 30 cycles of a 60 Hz. power supply, that automatic resumption of operations may safely proceed, without damage, while the economic losses due to a high frequency of shutdowns, each requiring a manual startup, are severe.

The mere introduction of a timing device to prevent the opening of power circuits during very short power interruptions does not solve the problem, however, since each of many suboperations must have its own power control that opens when the power is interrupted. The reason for the individual controls is that the restart can then be manually operated in the event that the interruption continues too long. Where, for

example, a large plurality of strands are being processed, each' of the spindle clutches for taking up the strands must be in dividually restarted after a long shutdown, and for this reason relays must be provided that will hold the individual circuits open after the power fails. Unfortunately, in the absence of prohibitively expensive hardware for each subprocess, these circuits have necessarily remained open after short interruptions even though the main circuit has not opened, so that the benefits of the timing device could not be realized.

SUMMARY In an electrical power supply system for an operation comprising a plurality of suboperations each requiring a supply of electric power, where the suboperations are subject to malfunction upon automatic restart after a shutdown of sufficient duration, we have invented the improvement comprising a first timer relay means comprising switch means, with the timerrelay means closing the switch means a preselected brief time following the energizing of the timer relay means, the switch means opening essentially without delay upon the deenergizing of the timer relay means. Our improvement also comprises a second timer relay means comprising switch means, with the timer relay means opening the switch means a preselected brief time following the deenergizing of the second timer relay means, the switch means closing essentially without delay upon the energizing of the second timer relay means.

In addition, our improvement comprises a first switching relay means comprising a switch means that is normally open and controls the current to a plurality of the suboperations and is itself controlled by the switch means of the second timer relay means, and also comprises a plurality of pushbutton means, a like plurality of local relay means and another like plurality of normally closed, remotely controlled switch means, each of the local relay means comprising a local switch means, each of the local switch means being normally open and controlling, in parallel with one of the pushbutton means and one of the remotely controlled switch means, the energizing of its associated local relay means and one of the suboperations, and being itself controlled by the switch means of the second timer relay.

Finally our improvement comprises gang relay means conthe first timer relay, whereby, upon the interruption of power for a period of time not exceeding the preselected time setting of the second timer relay means, the suboperations will resume without activation of the pushbutton means, and upon the interruption of power for a period of time exceeding said preselected time setting, and the resumption of power, each of the suboperations will start without delay upon, and only upon, the activation of its associated pushbutton means.

Our invention has particular application where the suboperations comprise the processing of strands and the interruption of power would create an accumulation of slack in the strands, and where the power supply is 60 Hz. and the preselected time for the second timer relay means is about 30 cycles.

We have invented the method of controlling the electrical power for a plurality of suboperations from a common electrical supply to avoid shutdown during very brief power interruptions, by the steps of timing a main circuit that feeds power to all the suboperations so that it remains closed for a preselected brief period of time after power failure, opens upon the expiration of the time period, and closes again essentially without delay upon the resumption of power. Our method comprises the steps of opening a first switch in each of the suboperations when the power fails, automatically closing a second switch that short circuits the first switch in each of the suboperations when the power fails and simultaneously, automatically opening each of the second switches again after, and only after, a preselected time period following the resumption of power, thereby providing time for the activation of the reclosing of the first switches.

BRIEF DESCRlPTlON OF THE DRAWlNG HO. 1 shows an idealized side view of a suboperation using our invention.

FIG. 2 shows a diagram of a controlling circuit of our invention.

FIG. 3 shows a diagram of circuits controlled by the circuit of F IG. 2.

DETAILED DESCRIPTION OF A PREFERRED EMBODlMENT Referring first to FlG. 3 a main power supply 9 is the sole electrical supply line for an operation 10 that comprises a large number of suboperations of which suboperations 11, 12, 13 are represented in FIG. 3. ln the embodiment described these suboperations comprise the activation of a solenoid 14 (F IG. 1) of a clutch 15 that brings an idler roll 16 into engagement with drive wheel 17, powered by a motor 18, and driven wheel 19 mounted to rotate a takeup spool 21 for a strand 22 being processed by an oven or other apparatus 23, of which many kinds are known for which the present invention has application. If there is an interruption in the supply 9 the motor 18 will, of course, stop and the clutch 15 will disengage. When the motor 18 stops the spool 21 will also soon stop but, because of the inertia of the various elements of the processing operation, such as a large payoff reel 24 from which the strand is being supplied, strand will continue to feed through the process for awhile and form a slack loop upstream of the spool 21. The motor 18 operates at a preselected torque to keep a proper tension in the strand and if the motor and clutch should reengage automatically upon the resumption of power after too much slack strand had accumulated, the motor would race and the spool 21 pick up sufficient speed to snap and damage the strand 22 when the slack was all taken up. For this reason and also to provide operator control over the initial start up of the operation, suboperation 11 is protected by a relay 26 and its associated switch 27 which is normally open and closes only when current passes through the coil of the relay 26. Since the switch is in series with the coil the energizing of the circuit has the effect of locking in the relay 26 and its switch 27 in the usual manner. Upon start up this energization is accomplished by manually operating a pushbutton 28.

Power for the operation'lo is supplied from a transformer 19 through a normally open switch 31 that is associated with a relay coil 32 (FIG. 2) in a circuit energized from the supply 9 by a transformer 33. A timer relay 34 having an associated normally open switch 36 with which the relay coil is in series and which is parallel to a pushbutton 37 is energized from the transformer 33. For the timer relay 34 we prefer to use Agastat Timing Relay Model 2422AA, obtainable from the Agastat Division of the Elastic Stop Nut Corporation of America, Elizabeth, N. I. When the supply circuit opens, the timer relay 34 delays 30 cycles of the 60 cycle power current before opening the switch 36 but when power returns to energize the relay coil the switch closes without any appreciable delay. Thus if there is an interruption in the power supply that is briefer than 30 cycles the switch 36 will not open at all and when the current resumes it will pass through the coil 32 and close the switch 31 thus supplying power to all the suboperations ll, 12, 13 etc. If, however, the interruption lasts for longer than 30 cycles, upon resumption the switch 36 will be open and current will not flow through the relay 32 until the pushbutton 37 is contacted manually. In addition to the timer relay 34 we have provided a timer relay 38 such as Agastat Timing Relay Model 24l2AA with an associated switch 39 in series with a relay 41. The switch 39 is normally open and opens without delay when the coil of the relay 38 is deenergized. When the coil of the relay 38 is reenergized, however, the switch does not close immediately but is delayed for some preselected period of time from 10-30 cycles determined by considerations herein below explained The relay 41 is associated with a plurality of normally closed switches 42 in parallel with the pushbuttons 28 and switches 27. When the power is on and the suboperations ll, 12, 13 are proceeding normally the switches 36, 39, 31, 27 are closed and the switches 42 are open. Upon a power failure the switches 39, 31, and 27 open immediately, the switch 36 and the switches 42 close immediately and the switch 36 remains closed for 30 cycles. [f power is resumed within the 30 cycle time period the switch 36 does not open at all so that the resumption of power energizes the relay 32, closing switch 31, and since the switches 42 have been closed, energizes the relays 26 to close the switches 27 so that each of the suboperations 11, 12, 13 is able to continue without manual control. The motors 18 start, the clutches l engage and the spools 21 take up wire which has not been slackened sufficiently to be damaged. After the power has been resumed for from to 30 cycles the timer relay 38 closes the switch 39, energizing the relay 41 to reopen the switches 42. The delay time for the timer relay 38 need be only sufficient to permit the relays 26 to close the switches 27 before the switches 42 are reopened.

In the event that a power interruption exceeds the 30 cycle duration, and then resumes, the current will find the switch 36 open and consequently the switch 3] will remain open until the pushbutton 37 is contacted manually. Even after such contact both switches 27 and 42 will be open, the switch 42 having opened shortly after power was resumed, and none of the suboperations will be energized until the pushbuttons 28 are contacted, whereupon the switches 27 will close. Signal lamp 42 and individual stop pushbuttons 43 are conventional.

ln the electrical supply system described for the operation 10 the plurality of suboperations 11, l2, 13 each require the supply 9 of electric power and are subject to malfunction due to slacking of the wire 22 after a shutdown of sufficient duration, such as one much exceeding 30 cycles. In our improvement the first timer relay means 38 closes the first switch means 39 a preselected brief time following the energizing of the timer relay 38, but the switch 39 opens essentially without delay upon the deenergizing of the relay 38. A second timer relay means 34 comprises the second switch means 36 that closes essentially without delay when the means 34 is energiled- The first switching relay means 32 comprises a third switch means 31 which is normally open and controls the supply of electric current to the plurality of suboperations 11, l2, 13. The second switch means 36 controls the current energizing the first switching relay means 32. Our system comprises the plurality of pushbutton means 28, like plurality of local relay means 26 and like plurality of normally closed, remotely controlled switch means 42, with each of the local relay means 32 comprising a local switch means 27 that is normally open and controls, in parallel with one of the pushbuttons 28 and one of the switches 42, the energizing of one of the suboperations, such as suboperation 11, and is itself controlled by the switches 42. The energizing of this gang relay is controlled by the first switch means 39 so that upon the interruption of power for a period of time not exceeding 30 cycles the suboperations 11, 12, 13 will resume without activation of the pushbuttons 28, and, upon the interruption of power for a period of time exceeding 30 cycles, and the resumption of power, each of the suboperations 11, 12, 13 will start only upon the activation of its associated pushbutton 28.

We claim:

1. In an electrical power supply system for an operation comprising a plurality of suboperations each requiring a supply of electric power, said suboperations being subject to malfunction upon automatic restart after a shutdown of sufficient duration, the improvement comprising:

A. first timer relay means comprising first switch means, said timer relay means closing said switch means a preselected brief time following the energizing of said timer relay means, said switch means opening essentially without delay upon the deenergizing of said timer relay means,

B. second timer relay means comprising second switch means, said second timer relay means opening said second switch means a preselected brief time following the deenergizing of said second timer relay means, said second switch means closing essentially without delay upon the energizing of said second timer relay means,

C. a first switching relay means comprising a third switch means, said third switch means being normally open and controlling the supply of electric current to a plurality of said suboperations, said second switch means controlling the current energizing said first switching relay means,

D. a plurality of pushbutton means, a like plurality of local relay means, and a like plurality of normally closed, remotely controlled, switch means, each of said local relay means comprising a local switch means, each of said local switch means being normally open and controlling, in parallel with one of said pushbutton means and one of said remotely controlled switch means, the energizing of its associated local relay means and one of said suboperations, and being itself controlled by the switch means of said second timer relay means, and

E. gang relay means controlling said remotely controlled switch means, energizing of said gang relay means being controlled by said first switch means whereby, upon the interruption of power for a period of time not exceeding the preselected time setting of said second timing relay means, said suboperations will resume without activation of said pushbutton means, and, upon the interruption of power for a period of time exceeding said preselected time setting, and the resumption of said power, each of said suboperations will start only upon the activation of its associated pushbutton means.

2. The system of claim 1 wherein said suboperations comprise the processing of strands and the interruption of power creates an accumulation of slack in said strands.

3. The system of claim 1 wherein said power supply is 60 Hz. and said preselected time for said second timer relay means is about 30 cycles of said supply.

4. The method of controlling the electrical power for a plurality of suboperations from a common electrical supply to avoid shutdown during very brief power interruptions, comprising the steps of:

A. timing a main circuit-feeding power to all of said suboperations to remain closed for a preselected brief period of time after power failure, to open upon the expirationof C. automatically Closing a second switch short circuiting said period, and'to close again essentially-without delay D. simultaneously automatically opening each of said Upon the resumption f P i a second switchesafter, and only after, a preselected period B' P a Switch in each of Said suboperafiqns of time following the resumption of power, thereby power I providing time for activation of the closing of said first said first switch in each of said suboperations upon said Swnches' power failure,

Claims (4)

1. In an electrical power supply system for an operation comprising a plurality of suboperations each requiring a supply of electric power, said suboperations being subject to malfunction upon automatic restart after a shutdown of sufficient duration, the improvement comprising: A. first timer relay means comprising first switch means, said timer relay means closing said switch means a preselected brief time following the energizing of said timer relay means, said switch means opening essentially without delay upon the deenergizing of said timer relay means, B. second timer relay means comprising second switch means, said second timer relay means opening said second switch means a preselected brief time following the deenergizing of said second timer relay means, said second switch means closing essentially without delay upon the energizing of said second timer relay means, C. a first switching relay means comprising a third switch means, said third switch means being normally open and controlling the supply of electric current to a plurality of said suboperations, said second switch means controlling the current energizing said first switching relay means, D. a plurality of pushbutton means, a like plurality of local relay means, and a like plurality of normally closed, remotely controlled, switch means, each of said local relay means comprising a local switch means, each of said local switch means being normally open and controlling, in parallel with one of said pushbutton means and one of said remotely controllEd switch means, the energizing of its associated local relay means and one of said suboperations, and being itself controlled by the switch means of said second timer relay means, and E. gang relay means controlling said remotely controlled switch means, energizing of said gang relay means being controlled by said first switch means whereby, upon the interruption of power for a period of time not exceeding the preselected time setting of said second timing relay means, said suboperations will resume without activation of said pushbutton means, and, upon the interruption of power for a period of time exceeding said preselected time setting, and the resumption of said power, each of said suboperations will start only upon the activation of its associated pushbutton means.

2. The system of claim 1 wherein said suboperations comprise the processing of strands and the interruption of power creates an accumulation of slack in said strands.

3. The system of claim 1 wherein said power supply is 60 Hz. and said preselected time for said second timer relay means is about 30 cycles of said supply.

4. The method of controlling the electrical power for a plurality of suboperations from a common electrical supply to avoid shutdown during very brief power interruptions, comprising the steps of: A. timing a main circuit-feeding power to all of said suboperations to remain closed for a preselected brief period of time after power failure, to open upon the expiration of said period, and to close again essentially without delay upon the resumption of power, B. opening a first switch in each of said suboperations upon said power failure, C. automatically closing a second switch short circuiting said first switch in each of said suboperations upon said power failure, D. simultaneously automatically opening each of said second switches after, and only after, a preselected period of time following the resumption of power, thereby providing time for activation of the closing of said first switches.

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