NOV. 19, 1946. ' H_ J; BlcHsEL 2,411,358 CONTROL CIRCUIT Filed Sept. 19, 1944 (as v 39 m 45 -' - o + A 15/ 4~ 1: 29 3/ f FELL ' 27 ‘ may“ Z’ H ,7 . 7' Load + k:Z3 WITNESSES: 54 jg > . /3 lllllllli lNVENTOR - HarryfB'c/vsel. _ ATTORNEY Patented Nov. 19, 1946 2,411,358 UNITED ‘ STATES PATENT OFFICE ' ‘ ‘ ' 5 2,411,358‘ ' ‘ . CONTROL CIRCUIT Harry J'.‘ Bichsel, " Pittsburgh, Pa., assignor to Westinghouse Electric Corporation, East Pitts burglnPaL, a corporation of Pennsylvania . . Application September 19, 1944, Serial No. 554,783 6 Claims. (Cl. 315-274) . 1 2 v ‘This invention relates to an electric discharge valve of the arc-like type and has particular relation to control apparatus for rendering the novel control arrangement for rendering an elec tric discharge valve of the arc-like type conduc tive at a desired instant, which arrangement is valve conductive. highly reliable in operation. ‘ ‘ _ Electric discharge valves of the arc-like type,’ such as thyratrons, include an anode, cathode . A further object of my invention is .to provide a new and improved control arrangement for rendering an electric discharge valve of‘ the arc and a control electrode. It is a well known char acteristic of such valves that they remain non like type conductive at an instant determined by conductive as long as the (control electrode-to the operation of a relay. cathode voltage is less positive than a predeter_ 10 My invention arises from the realization that mined critical voltage. If_ an anode-to-cathode the occasional failures in previous systems as voltage exists which is greater than the break described was caused by the bouncing of the con down voltage of the valve, with the anode posi tacts of the relay. The contacts of most relays tive, the valve becomes ‘conductive the instant other than very special expensive ‘relays, bounce the control electrode-to-cathode voltage becomes 15 upon closing. This bouncing causes a disconti more positive than the critical voltage. The nuity in the voltage impulse which is applied be‘control electrode then loses control of the valve tween the control electrode and cathode of the which continues to conduct until the anode-to valve in the prior arrangements. If the relay cathode voltage is reduced below the arc drop contacts bounce at the right moment, the peak of. the valve. This feature is employed widely portion of the voltage impulse may be missed where ‘it is desired to render the valve conduc completely, so that the valve is not rendered con tive ‘at a predetermined instant.‘ Often an alter ductive. ,. hating potential or other potential having a In accordance with my invention, a biasing steep-wave front is impressed between the control potential is impressed between» the control elec electrode and cathode so that the instant at which the; control electrode becomes more positive with respect to the cathode than the critical voltage ' ) trode and cathode of the valve tending to main-‘ tain the former less positive with respect to the latter than the critical voltage of the valve.‘ An energy storage device is connected in parallel cir may-be accurately predetermined. A peaking transformer energized from an alternating poten cuit relation with an impedance, such as a re-» tial ‘source is frequently used for this purpose. 30 sister, and the parallel storage device and im~ 'Such arrangements ordinarily operate quite pedance are connected in a series circuit with a satisfactorily. However, under certain conditions normally closed switch which may be the con serious di?iculties are encountered. In a num ber of cases it is desirable to render a valve con tacts of ‘a relay. A direct current is then, supplied‘ through the series circuit and serves to store up energy in saidstorage device. When the switch ductive at the instant that-some other ‘operation takes place, for, example, when a relay is oper ated‘. Under such circumstances, it has been cus tomary. to provide a voltage which is applicable to the control electrode. and cathode upon the is thereafter opened, the energy‘ so stored is re leased to eifect current flow through the impede ance. Means are provided to make the control electrode more positive with respect to the cath closure of the relay contacts. Frequently a pre 4.0 ode than the critical voltage and thereby render charged capacitor is discharged through a dis the valve conductive in response to the release of’ charge circuit including‘the primary of a peaking transformer when relay contacts in the discharge circuit-are closed, the secondary winding of the peaking-‘transformer being connected in circuit 45. betweenthe control electrode and» cathode of the valve. _Howev,er,.it has been found that such an the energy. Since the valve becomes conductive‘ arrangement is unreliable in that it occasionally teristic of my invention are setforth with greater particularity in the accompanying claims. The fails to render the, valve conductive at the instant desired. ' e r it . ,.,It,is accordingly an object of my invention to providea: novel control arrangement for an elec tri dischargefvalve. of the arc-like type for ren 5,0 upon the opening of the switch, the bouncing of the contacts if the switch is formed by the con tacts‘ of a relay obviously does ‘not affect the ‘ instant of ?ring of the valve. ‘ The novel features whichI ‘consider charac- ' invention itself, however, both as to the organ ization and method of operation, together‘with additional objects and advantages, may be best der gfbllé; valve conductive at a desired instant. understood from the following description of a speci?c ‘ embodiment when read in connection ,qj‘qnnother object of my inventionisto provide a with the accompanyinaidrawingi in which ‘the. 2,411,358 3 . > 4 zero and the valve 3 becomes nonconductive. If the push-button switch 9 is then allowed to re close, the valve may be rendered conductive again by reclosure of the push-button switch 41. single ?gure is a circuit diagram of an embodi ment of my invention. ' As shown in the drawing, an electric discharge valve 3 of the arc-like type, preferably a thyra a circuit extending from the anode through a. The purpose of the adjustable resistor 3| in circuit with the primary winding 21 is to limit normally closed pushbutton switch, 9, a load NY ‘the vmagnitude of the direct ‘current supplied and a source of potential such: as 1a battery [3; to the cathode. The battery [3 produces a'volté age between the anode 5 and the cathode ‘i which ,10. is greater than the breakdown voltage of they ' missible with the particular transformer em ployed. It is therefore understandable that the V tron, has its anode 5 and cathode ‘i’ connected in or valve, with the anode 5 ‘being positive. The control electrode or grid E5 of the valve 3 is connected to the cathode 'i. in, a‘ circuit which, extends from the grid through a grid'resistor; H, the secondary winding it of a transformer 21, and a source of biasing potential such-as a battery 23 to the cathode. In addition a loading resistor through the primary winding to the; value per right end of resistor 34 may be connected to any point, along the circuit between the contacts 33, and the right-hand end of primary winding 21 without changing“ the operation of the circuit if 15" the .value of, the‘ resistor is selected properly in ‘accordance with the point of connection. It is. also to be understood that while switches 25 is connected in shunt across the secondary‘ winding iii. The battery 23 tends to maintain 20 the grid’ 15 less positive‘ with respect to the oath ode,v 7' than the critical voltage‘ of the valve, and thus maintain the valve non-conductive. 9 and 4.1, are shown as push-button switches, various other well known means may be em ployed to e?ect energization and deenergization ‘of-v the corresponding circuits. 'Contacts33'may also be replaced with other switch means if de sired, the valve being rendered conductive upon the opening of such other switch means. It is The primary winding 21' ofthe transformer 2! is connected across a source of direct-current 25 also ‘to be noted that an alternating potential may be employed in the anode circuit of the'valve potential 29 through an adjustable resistor 31 and in place of the battery l3; Under such circum the normally closed contacts 33 of a relay 35. stances energization of the relay 35 should be co Another resistor 34 is connected in shunt across ordinated with the alternating potential to oc the primary winding 21. ' The sourceof'direct-ourrent potential 29 is il lustrated as a resistor which is supplied from al ternating potential supply lines 36 and 31 through a transformer 3%, a full wave recti?er Lil and-"a ?ltering capacitor 43,. Any other source of direct-current potential of the proper mag nitude and polarity may, of course, be used. ' The contacts 33 of the relay 35 may be opened by energization of the relay coil 45. This coil is cur during the half period in which the anode 5 of the valve is positive. ' ' While I have shown and described a specific embodiment of my; invention, I am well aware that many modi?cations thereof are possible without departing from the spirit of the inven tion. It is not my intention thereforeto limit my invention to the speci?c embodiments'hown. I claim as my invention?" ' ,1. Control apparatus for an electric discharge mally open push-button switch 41 across the al 40 valve of the arc-like type having an anode, cath ternating potential supply lines 36 and 31. ode and control electrode, comprising a control, circuit connected from said control electrode to ~ While the relay contacts 33 are closed, direct said ' cathode and‘ including biasing potential current ?ows from the source 29 through the con means tending to maintain the former less posi tacts 33, adjustable resistor 3!, and the parallel tive with respect to the latter than the critical connected primary winding 2'! and resistor 34. voltage of the valve, an energy storage device, Since the impedance of’ the resistor 34 is high impedance means connected in parallel circuit compared to the impedance of the primary wind relation with said device, a normally closed’ ing 21, most of the current flows through the primary winding and stores up energy in the switch connected in a series circuit with said, transformer. If push-button switch it‘! is then 50' paralleled device and impedance means, and means adapted to supply direct current‘ through closed, relay coil 45 is energized and contacts 33 said series circuit, whereby energy stored in said: are opened. As a result, the supply of direct cur device by said direct current is released to ef rent is interrupted and the energy storedin the transformer‘is released. Some of the energy so fect, current’ ?'ow' through said impedance means released tends to keep the~ current ?owing when said switch is opened, said control, circuit: illustrated as connected in circuit with a nor ‘ through‘ the primary winding 2’! in the same di rection as the current previously supplied from the source 29 because of the inductive eifect of the . primary- winding." Consequently, current ?ows in the circuit made vup-of the primary wind ing 21, and the resistor 34‘. ' 7' being coupled to said device to make said con trol electrode more positive withrespect to said cathode than said critical'voltage in response to the release of said energyf ' 2. C‘ontrol‘apparatus, for an electric discharge valve of“ the arc-like type. having’ an anode, cath ' * The rapid cha‘n'ge'of ?ux in the transformer caused by the release ofqenergy stored therein ode- and control electrode, comprising atrans former having a primary and'a' secondary wind; produces a voltage impulse across the secondary winding 59 which is of such polarity and mag-. ing, circuit means connecting v"said secondary’ ' nitude as to overcom'ethe biasing potential ofthe batte'ry'i23 and"render the ‘valve 3 conductive. The magnitude of the voltage impulse may be de termined bythe size of the resistor 34. ‘ . After the valve is conductive the push-button switch 41 may be released, to eifect reclosure of contacts 33. The valve 3' then continues to con duct current until the QuSh-buttQn'sWitchQS is opened; With the opening of-th'e'» push-"button ‘s’witchQ-“the- anode-to-cathode voltage drops to winding‘ ‘in 'a' ‘circuit between; ‘said control" elec trode and cathode including biasing potential .means'tending to maintain the control electrode less positive with, respect to the cathode than the1 critical voltage‘ of sa'idvalve, impedance means connected in parallel circuit relation with said primary winding, a normally closed‘ switch“ ‘con nect‘ed in a series circuit'with said paralleled‘ im-; pe-dance means and primary winding, and means , adapted to supply‘ direct current through said“ series circuitv of such polarity that the'rele'a‘se ' '5 2,411,358 of energy stored thereby in said transformer, as effected by opening of said switch, causes a volt age impulse across said secondary winding to render said control electrode more‘positive with respect to the cathode than said critical voltage. 3. Control apparatus for an electric discharge 6 5. A control system comprising an electric dis charge valve of the arc-like type having an anode, cathode and control electrode, means for impressing a positive voltage between said anode and cathode, a control circuit connected from said control electrode to said cathode and in cluding biasing potential means tending to main tain the former‘less positive with respect to the latter than the critical voltage of the valve, an valve of the arc-like type having an anode, cath- ' ode and control electrode, comprising a trans former having a primary and a secondary wind ing, circuit means connecting said secondary 10 energy storage device, impedance means con Winding in a circuit between said control elec nected in parallel circuit relation with said de trode and cathode including biasing potential vice, a normally closed switch connected in a means tending to maintain the control electrode series circuit with said paralleled device and im less positive with respect to the cathode than the pedance means, and means adapted to supply critical voltage of said valve, impedance means \ direct current through said series circuit, where connected in parallel circuit relation with said by energy stored in said device by said direct cur primary winding, a relay having normally closed rent may be released to e?ect current ?ow contacts connected in a series circuit with said through said impedance means when said switch paralleled impedance means and primary wind a is opened, said control circuit being coupled to ing, means adapted to supply direct current 20 said device to make said control electrode more through said series circuit, and means for oper positive with respect to said cathode than said ating said relay to open said contacts, the polar critical voltage in response to the release of said ity of said direct current being such that the re energy whereby said valve is rendered conduc lease of energy stored thereby in said trans tive when said switch is opened. former, as e?ected by opening of said contacts, 6. A control system comprising an electric causes a voltage impulse across said secondary discharge valve of the arc-like type having an winding to render said control electrode more anode, cathode and control electrode, means for positive with respect to the cathode than said impressing a positive voltage across said anode critical voltage. and cathode, a transformer having a primary 4. Control apparatus for an electric discharge and a secondary winding, circuit means con valve of the arc-like type having an anode, cath ode and control electrode, comprising a trans former having a primary and a secondary wind ing, circuit means connecting said secondary winding in a circuit between said control elec trode and cathode including biasing potential necting said secondary winding in a circuit be tween said control electrode and cathode includ ing biasing potential means tending to maintain the control electrode less positive with respect to the cathode than the critical voltage of said valve, a resistor connected in parallel circuit relation , means tending to maintain the control electrode with said primary winding, a normally closed less positive with respect to the cathode than switch connected in a series circuit with said the critical voltage of said valve, a resistor con paralleled impedance means and primary Wind nected in parallel circuit relation with said pri 4.0 ing, and means adapted to supply direct cur mary winding, a normally closed ‘switch con rent through said series circuit of such polarity nected in a series circuit with said paralleled re that the release of energy stored thereby in said sistor and primary winding, and means‘ adapted transformer, as effected by opening of said to supply direct current through said series cir switch, causes a voltage impulse across said sec— cuit of suchpolarity that the release of energy 45 ondary winding to render said control electrode stored thereby in said transformer, as effected more positive with respect to the cathode than by opening of said switch, causes a voltage im said ‘critical voltage whereby said valve is ren pulse across said secondary winding to render dered conductive when said switch is opened. said control electrode more positive with respect to the cathode than said critical voltage. 50 HARRY J. BICHiSEL.