US2473916A - Relay system - Google Patents

Description

June 21, 1949 F. o. SNYDER RELAY SYSTEM Filed Aug. 15, 1946 lNVENTOR fFeder/d 1 .511 yoer:

WITNESSES: 5.477%

BY fwv/ ATTORNEY Patented June 21, 1949 RELAY SYSTEM Milton, Mass, 'assignor 'to Frederick H. Snyder,

'Westinghouse Electric Corporation, East Pittsburgh, la., a corporation of Pennsylvania Application August 15, 1946, Serial N0. 690,795

6 Claims.

My invention relates to relay systems which automatically stop the operation of machinery in response to the occurrence of a fault in any one of a large number of points under supervision. Such systems are being used, for instance, in warping, weaving, knitting, and other textile machinery or other strand, thread, yarn, wire fab-ricating apparatus in order to stop an electric drive motor when any of the fabricated individual strands of material breaks or unduly reduces its tension.

It is known 'to connect the fault-responsive element in systems of the above-mentioned type with the respective grid circuits of electronic trigger tubes which, when fired, causes the motor contactor to drop out; and it has been proposed to connect each trigger tube with a signal lamp in order to indicate to the operator the location of the fault.

The invention, more specifically, relates to selectively indicating relay systems :of the justmentioned kind and has for its object to improve these systems as to reliability of selective indication and also in such a manner as to greatly reduce the skill and attention required from the operator, adjuster or supervisor without appreciably increasing the amount .or cost of equipment used as compared with the known systems.

When in the .knownsystems, the machinery is stopped due to the occurrence of a fault, such as a yarn break in a knitting or other textile machine, it happens frequently that all threads become slack with the result that many or all fault-responsive elements fire therespective trigger tubes. Then many or an indicator lamps will glow thus making it difficult or impossible to determine the one faulty thread that caused the stoppage. It *is also necessary that after a fault-responsive stopping of the machinery, if the location of the fault is properly indicated by a single glowing lamp, this location be memorized or marked before the machine is readjusted because the adjusting procedure requires usually a slackening of all threads and hence may cause a response of all drop wire switches.

Any such subsequent elimination of the selective indication-is securely prevented in systems according to the present invention so that the operator will always know where the fault occurred regardless of a subsequent slackening of the threads. This result is achieved, without the necessity of using relays or the like auxiliary devices in addition to those required for the faultcontrolled motor control performance, by interlocking the individual fault-controlled circuits-oi CJI the system so that the first-responding circuit, when stopping the motor and causing the one appertaining signal to indicate, renders all other circuits inoperative and thus prevents a subsequent closing of other drop wire contacts or the like 'feeler elements from actuating additional signals.

These and other'objects and features of the invention will be understood "from the following description of theembodiment of a textile machine with drop-wire feeler contacts exemplified by the schematic illustraticnand circuit diagram shown in the drawing.

For the sake of completeness and in order to facilitate understanding the operation, examples of numerical values for the electrical components of the system are hereinafter given. These numericalexam-ples are interrelated in referring all to a single embodiment of proved quality of performance. It should b'e' keptin-mind, however, that theratingsof the individual element and their proportion-to one another-may be varied within wide limits and that the values to be chosen will be determinedbythe-requirements or desiderata of each-particular application of the invention.

The illustrated textile :machinery is schematically represented as having a creel type device with a number of yarnreels ;l',2,'3, 4 from which theyarn passes through a guide .5 onto a beam 6. The individual threads pass through the eyes of drop wire switches 61, S2, S3, 84 respectively whose contacts are kept open as long as the appertaining threads-are unbroken and sufiiciently taut. The beam 6 is driven'by an electric motor M -under "control "by ,a :contactor C whose main contacts land "8, when closed .by the relay coila, connectthe'motorto the buses LI and L2 of an alternatingecurrent "line. While the just-mentioned creel'and'beam device is characteristic of warping machinery, this particular type machinery is chosen merely for simplicity of illustration; and it should be understood that the invention proper, as embodied by the elements described belo is similarly applicable to other yarn, thread, strand or .wire fabricating machinery.

The recoil circuit of .contactor .6 extends .between buses Ll andJLiZ through. astart contact BI and a stop contact" B2, both preferably designed as push-button-switches. .Further details of this coil circuit will be described in a later place. A backcontactinrof con-tactor Clies across the startlbutton Bl. IKI-Ience, when the start button ls temporarily ilepr-essediby the :operator, and

contactor C picks up to start motor M, the contact I closes a self-sealing circuit so that contactor C stays energized and motor M continues running until the stop button B2 is actuated or the coil circuit interrupted by the fault responsive devices now to be described.

Associated with the fault-responsive feelers on drop wire contacts SI, S2, S3, S4are electromagnetic relays RI, R2, R3,'R4 respectively. Relay RI has two contacts II and I2 controlled by a coil i3. An indicator I4, for instance, a neon lamp (e. g., .5 watts) is connected across coil I 3. An electronic trigger tube such as a thyratron (e. g., type No. 2050) has its plate circuit also connected across coil 93. The grid of tube I5 is connected through a resistor It (e. g. megohm) with the drop wire contact SI. A capacitor I7 (.001 mfd.), a resistor I 8 (2500 ohms), and a resistor I9 (10,- 000 ohms) are further associated with the tube and relay circuits appertainin to drop wire contact Si.

The tube and relay circuits associated with the other drop wire contacts are similar to those of contact SI. That is, the elements denoted by 2i through 29 and appertaining to drop wire con tact S2, elements 3! through 39 appertaining to drop wire contact S3, and elements M through 49 appertaining to drop wire contact S4 correspond to the above-described elements II through I9 associated with drop wire contact SI.

The trigger tubes I5, 25, 35, have their respective cathode heaters series connected in a heater circuit 5%! which is energized by constant voltage (28 volts) from the secondary M. of a transformer T whose primary 52 is connected to buses Li and L2 through a main switch S. Another secondary 54 (130 volts) of transformer T is connected to the input terminals of a full-wave rectifier 55. A filterin or smoothing capacitor (30 mid.) lies across the output terminals of the rectifier. A negative output lead 51 and two positive output leads 58 and 59 are shown in the drawing. A voltage dividing resistance combination is connected across leads 51 and 59 and comprises three series-connected resistors 60 (25,000 ohms), 6| (3,000 ohms), and 62 (60 ohms), Interposed between the lead 58 andthe positive rectifier terminal is the contact 63 of a relay FR whose coil 64 is series-connected in the heater circuit 50. A normally closed reset contact, preferably of the push-button type, is denoted by B3.

The above-mentioned coil circuit of the motor contactor M extends serially through the contacts II, 2!, ti and 4|. Hence, the motor M cannot be started unless all relays RI, R2, R3 and R 2 are energized. To this end, the main switch S is first to be closed. This causes the transformer T to be energized. A rectified voltage now appears across leads 5'! and 59. Simultaneously, the heater circuit 50 is energized. Relay FR picks up and closes its contact 63 so that the rectified voltage is also effective between leads 57 and 53. The voltage drop along resistor 62 is now impressed between the common cathode lead 65 of tubes I5, 25, 35, 5 and the respective grid circuits in such a manner that the tube of each grid is held on blocking potential as long as the appertaining responsive contact is open. As a result, all tubes are normally nonconductive. Coil I3 of relay R! is now energized in the circuit:

II and I2. their an- 3I, 32,,

42 are also closed. The voltage drop now obtaining across the coils I3, 23, 33, it suffices to light the respective lamps I :2, 24, 34 and 44. As long as all lamps are lit, the system is in condition for operating the motor M as described in the foregoing.

The feeler contacts SI, S2, S3, S4 have a common positive lead 66 which is connected, through relay contacts I2, 22, 32, 42, to a point 67 between resistors 60 and GI. When a fault occurs so that, for instance, feeler contact SI drops out, it connects point iii; of the appertainin grid circuit with point 67. Consequently, point 68 changes its potential and becomes sufficiently positive, relative to the tube cathode lead 65, to cause firing of tube I5. The conductive tube It short-circuits the coil 23 so that relay RI drops out and opens contacts Ii and I2. The opening of contact Ii interrupts the circuit of coil 9. Hence, contactor 0 drops out and stops the motor M. Lamp 5 goes out and thus indicates to the operator that the trouble started at feeler contact SI. Due to the opening of contact I2 in relay RI, the com-- mon positive lead 66 of all feeler contacts becomes disconnected from point 61 of the voltage divider. In consequence, all feeler switches become ineffective to fire the respective thyratrons so that a subsequent slackening of the threads due to the stopping of the machinery or as a result of any manipulation by the operator has no effect on the condition of the relay system. That is, tube I5 remains conductive, relay RI dropped out, and lamp I4 dark while all other tubes remain non-conductive, all other relays picked up. and all other lamps lit. If any one of feeler contacts S2, S3, S4 drops out first, it causes firing of the appertaining tube so that the corresponding lamp will extinguish and the motor be stopped in the same manner as described above with reference to feeler contact SI. In any'such event,

the relay first responding brings about the dis-- connection of the feeler contact arrangement and thus secures a permanent selective indication, until the operator resets the system by opening the contact B3. This causes the thyratron then conducting to become deenergized and its corresponding relay to pick up again. If the fault is removed before the contact B3 is permitted to close its circuit, all the relays RI through R l will remain picked up with all thyratrons non-conductive, so that the motor M can be restarted by depressing the button BI.

Due to the fact that all tube filaments are connected in series with one another and in series with coil 64 of relay FR, this relay will cut-off the power supply to relays RI, R2, R3 and R4 and thus stop the motor M if any of the tube filaments burn out, if any one of the tubes gets loose in its socket, or if the filament voltage fails for any other reason.

Protection is also afforded if the main supply voltage fails because in this case the output volt age of the rectifier S5 becomes too low to hold relays RI, R2, etc. picked up. Hence, these relays will drop out and stop the motor.

While I have shown only four feeler contacts and four appertaining tube and relay arrangements, the invention can be used with any other number of fault-responsive elements of any kind, and these elements may be inter-connected to an equal number of tube and relay circuits, or the fault-responsive elements may be connected in groups to a smaller number of tubes and relays. In the latter case, the lamp appertaining to each relay and tube indicates the group of elements within which a yarn break is to be looked for after occurrenceof a stoppage.

Other modifications and variations will be obvious to those skilledin the-art. It should be understood, therefore, that the invention is not limited to the specific embodiment described in the foregoing but may be given axdifferent design or used for other than the illustrated type machinery without departing from the aboveexplained principles and within the scope of the claims attached hereto.

I claim as my invention:

1. An indicating protective control system for machinery for fabricating strand material and the like, comprising a motor, a contactor for controlling said motor, a plurality of differently located control elements responsive to faulty condition of the material, a 'plurality'o'f control assemblies having each an electromagnetic relay and an indicating means and including each a normally nonconductive electronic trigger tube in parallel connection to said relay, each of said relays having a contact and a relay coil for controlling said contact, an energizing circuit connected across said relay coils so as to cause said relays to be normally in picked-up condition and to drop out when said tubes are conductive, said tubes having respective grid circuits conected to said respective control elements so as to trigger said respective tubes when said elements respond to fault, circuit means disposed for providing trigger voltage for said grid circuits and having a circuit connection attached to said control elements and extending in series through said relay contacts so that when one of said elements has caused triggering of the appertaining one tube said control elements are rendered temporarily ineffective to thereafter trigger other tubes, said relays being connected to said contactor for controlling it to deenergize said motor when any one of said tubes is triggered.

2. In textile machinery for fabricating a multiplicity of threads, the combination of a drive motor, a contactor for controlling said motor, a multiplicity of fault responsive feeler contacts engageable by said threads, a multiplicity of control assemblies having each a normally nonconductive electronic trigger tube and including an electromagnetic relay and an indicating lamp controlled by said tube, said tube and said relay being connected in parallel to each other so that said relay is shorted when said tube is conductive, a direct-current circuit connected across said relays so as to cause them to be normally in pickedup condition, said tube having respective grid circuits connected to said respective control elements so as to trigger said respective tubes when said feeler contacts respond to fault, circuit means disposed for providing trigger voltage for said grid circuits and having a circuit connection attached to said contacts and controlled by said relays so that when one of said contacts has caused triggering of the appertaining one tube said feeler contacts are temporarily ineffective to thereafter trigger other tubes, said relays being connected to said contactor for controlling it to deenergize said motor when any one of said tubes is triggered so that then the indicating means pertaining to the triggered one tube indicates the fault location.

3. An indicating control system for machinery for fabricating strand material and the like, comprising a motor, a contactor disposed for controlling said motor and having a coil circuit, a plurality of control elements responsive to faulty condition of the material, a plurality of control assemblies having each an electromagnetic relay and an indicating means and including each an electronic trigger tube for causing said relay and said indicating means to change their respective conditions when said tube is triggered, said tubes having respective grid circuits normally under cut-off bias and connected to said respective control elements so as to trigger said respective tubes when sa'd elements respond to fault, circuit means disposed for providing trigger voltage for said grid circuits and having a circuit connection attached to said control elements and jointly controlled by said relays so that when any one of said elements has caused triggering of the appertaining one tube said control elements are rendered temporarily ineffective to thereafter trigger other tubes, said coil circuit extending in series through all said relays so that said motor can be operated-only when all said tubes are nonconductive and is deenergized when any one tube is triggered.

4. An indicating control system for machinery for fabricating strand material and the like, comprising a motor, a contactor disposed for controlling said motor and having a coil circuit, a plurality of control elementsresponsive to faulty condition of the material, a plurality of control assemblies having each an electromagnetic relay and an indicating means and including each a normally nonconductive electronic trigger tube in parallel connection to said relay, each of said relays having two contacts closed in the pickedup condition of the relay, a direct-current circuit connected across said relays so as to cause them to be normally in picked-up condition and to drop out when said tubes are conductive, said tubes having respective grid circuits connected to said respective control elements so as to trigger said respective tubes when said elements respond to fault, circuit means disposed for providing trigger voltage for said grid circuits and having a circuit connection attached to said control elements and extending in series through one of said contacts of each of said relays so that when one of said relays drop out all control elements are temporarily ineffective, said other contacts of said relays being series-connected in said coil circuit so that said motor can be operated only when all said tubes are nonconductive and is deenergized when any one tube is triggered.

5. With machinery for fabricating yarn, thread, strand, Wire and the like material, the combination of a motor for driving the machinery, a contactor for controlling said motor, a plurality of feeler contacts responsive to defects in material to be fabricated, a plurality of control assemblies having each an electro-magnetic relay and an indicating means and including each an electronic trigger tube, each of said relays having a normally closed relay contact and a coil for controlling said relay contact, said tube of each assembly being connected with the appertaining coil and with the appertaining indicating means for causing said coil and indicating means to change their respective conditions when said tube is triggered, said tubes having respective grid circuits normally under cut-off bias and connected to said respective feeler contacts so as to trigger said respective tubes when said contacts respond to fault, circuit means disposed for providing trigger voltage for said grid circuit and having a circuit portion connected to all said feeler contacts and extending serially through all said relay contacts so that when any one of said feeler contacts has caused triggering of the appertaining one tube all other feeler contacts are inelfective to thereafter trigger other tubes, said relays being connected to said contactor for controlling it to deenergize said motor when any one of said tubes is triggered so that then the indicating means pertaining to the triggered one tube indicates the fault location.

6. An indicating protective control system for machinery for fabricating strand material and the like, comprising a motor, a contactor for controlling said motor, a plurality of differently located control elements responsive to faulty condition of the material, a plurality of control assemblies having each an electromagnetic relay and an indicating means and including each a normally nonconductive electronic trigger tube in parallel connection to said relay, each of said relays having a contact and a relay coil for controlling said contact, an energizing circuit connected across said relay coils so as to cause said relays to be normally in picked-up condition and to drop out when said tubes are conductive, said tubes having respective grid circuits connected to said respective control elements so as to trigger said respective tubes when said elements respond to fault, circuit means disposed for providing trigger voltage for said grid circuits and having a circuit connection attached to said control ele ments and extending in series through said relay contacts so that when one of said elements has caused triggering of the appertaining one tube said control elements are rendered temporarily inefiective to thereafter trigger other tubes, said relays being connected to said contactor for controlling it to deenergize said motor when any one of said tubes is triggered, said tubes having respective cathode heaters, a heating circuit including said heaters in series connection with one another and having a relay connected with said energizing circuit for interrupting said energizingcircuit in response to occurrence of current failure in said heating circuit.

FREDERICK D. SNYDER.

REFERENCES CITED The following referemces are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 1,919,122 Oskow July 18, 1933 2,383,838 Auble Aug. 28, 1945 2,390,799 Linsenmeyer et al. Dec. 11, 1945 2,405,218 Lambach et al Aug. 6, 1946

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