US2532508A - Electronic interrupter - Google Patents

Description

Dec. 5, 1950 w. P. MENKHAUS 2,532,503

ELECTRONIC INTERRUPTER Filed Dec. 27, 1946 2 Sheets-Sheet 1 WMzerBMn/chaus,

INVENTOR,

Dec. 5, 1950 w. P. MENKHAUS 2,532,508

ELECTRONIC INTERRUPTER Filed Dec. 27, 1946 2 Sheets-Sheet 2 l w- 1 24 5 2w W A 3nnentor WaifenBMnk/ia us,

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(Ittorneg Patented Dec. 5, 1950 UNITED STATES PATENT OFFICE ELECTRONIC INTERRUPTER Walter P. Menkhaus, Philadelphia, Pa.

Application December 27, 1946, Serial No. 718,863

1 1 Claim.

The object of the invention is to provide improvements in electronic interrupters of widely separated maximum and minimum period limits of operation.

More particularly an object of the invention is to provide an interrupter of this type, which is adapted for use in controlling the operation of such devices as intermittent test apparatus, flash signs such as are used for advertising, warning and other devices by which the periods during which the controlled device is energized and deenergized may be the same, or in which these periods may be widely different, as for example as short as one-thirtieth of a second to a full minute or more.

A further object is to provide a completely automatic device of this class, which eliminates the present necessity of using any ,form of motor and commutator whatsoever, and which provides variable controls so the device can be set for predetermined periods of fon and old, whether such periods are equal or different.

And a more specific object is to provide a device of this nature, which comprises the assembly of an auto transformer, a relay, a rectifier and a thyratron tube, both fixed and variable potentiometers or resistors, switches, and fixed condensers, so interconnected as to provide a simple and compact device of low initial cost, relatively no cost of upkeep and readily adjusted and repaired by replacement of parts, and one which can be easily transported 'from place to place, consumes a minimum of current, and is highly ei ficient in operation.

Having thus described the objects in general terms, the invention comprises further details of construction and operation, which are hereinafter brought out in the following description, when read in conjunction with the accompanying drawings, in which Fig. 1 is a wiring diagram illustrating the elements comprising one e nbodi ment of the invention with appropriate electric connections; and Fig. 2 is a modified embodiment of the same.

Referring to Fig. .1 of the drawing, a two- .pronged plug i is employed to represent any suit able means for readily connecting the'device in an ordinary alternating current circuit, such as the widely used 110-115 volt, Bil-cycle, circuit of commercial and domestic installations so prevalent throughout the United .States.

One side of said plug is connected through a switch 2 to the primary winding 3 of a filament and bias transformer 3' of the iron-core type, the

secondary winding 4 of said transformer being connected to the respective filaments 5 and 6 .of a pair of tubes 1 and B, the first .of said tubes being a oneehalf wave rectifier and the other tube being of the thyratron type; The opposite end of the transformer primary is connected by a may to the opposite side oi said plug A continuation ll! of said primary winding 3 is also connected by a resistance i i to said opposite side of said plug, said resistance having a variable positioned tap l2, connected as hereinafter described.

From said switch 2 a wire i3 leads through a switch M to the coil of a relay l5, having in .sequence (when said relay is deenergized) a closed contact 15, three open contacts ii, i8 and i9, and a closed contact 2% The first-mentioned contact 56 is interposed between the wire i3 and the plate of the rectifier tube 1, the cathode of which tube is connected through a pair of variable resistances or potentiometers 2i and .22, a condenser 23 and Wire 2i to the second or opposite side of said plug as shown, said last-mentioned resistance 2?; being shunted by a switch 25.

The connection between said resistance 22 and said condenser 23 is connected by wire first through a fixed resistance 2'! to the control grid 28 of the second tube 8, and secondly through the open relay contact 18 to a variable resistance 29, fixed resistance 30 and second variable resistance 31 to a wire 32, which is connected to the wire 24, said last-mentioned variable resistance 3i being shunted by a switch 33.

The wire 34 that connects the resistance 21 to the control grid 23 of the second tube 8 is connected through a fixed resistance and the open relay contact 19 to a second fixed resistance 35 and thence to said wires 32 and 2 3. Said fixed resistance 35 is also connected through a variable resistance 3?, shunted by the closed relay contact 28, to the tap 12 of the resistance by a wire 3'8. it will also be'noted that the shield or suppressor grid 39 and cathode or" the tube 8 are connected by a common wire 4! both to the wires 32 audit, and also to a terminal 82. The opposite side of the relay I5 is connected to the plate of the tube 3. Wire i3 is connected through the open relay contact l? by a wire it to a second terminal 44.

In the embodiment of the invention herein described and illustrated, the following values are preferred as having been successfully tested and roved:

Variable resistance 21--56,0{l0 ohms Variable resistance 2210 megohms Condenser 234 microierad; 250 volt Fixed resistance 2-7-20 megohms; /2 Watt Variable resistance 29-56,00 ohms Fixed resistance 303,00 ohms; watt Variable resistance 31-l0 megohms Fixed resistance 3520 megohms; /2 watt Fixed resistance 3630 megohms; watt Variable resistance 37-1 megohm Variable resistance l1-1 megohm For using the improved interrupter, a chart is provided to show the combination of switches to to he closed and/or opened, and the adjustment of the respective resistances, in order to provide any desired period of energizing and deenergizing the controlled apparatus that may be connected to the output terminals 42 and 44.

For purposes of illustration, if the sign or other apparatus is to be energized for approximately two cycles and then deenergized for two cycles alternately, switches 25 and 33 are closed and the potentiometers or variable resistances 2i and 29 set at minimum. If for a widely different time of one minute on and one minute ofi, the same switches are all opened and the variable resistances 22 and 3! set at maximum. However, if instead it is desired that the controlled device shall be energized for a period of thirty seconds and deenergized for a period of fifteen seconds, switches 25 and 33 are opened and variable resistance 22 is set to give fifteen seconds of time, as shown on its dial, and variable resistance 3! is set to give thirty seconds time, as shown on its calibrated dial.

From the foregoing it will be apparent that an interrupter of wide range and simple adjustability and operation has been provided, and

that the values given are purely representative of what can be effected, without changing the general assembly of the several elements such as the condenser, resistances, switches, etc., while at the same time it is recognized that at this time the principles of operation may not be fully understood. However, it has been proved that with a given combination of switches opened or closed and variable resistances set in accordance with a set plan, on and off time can be established for any desired time duration that current is to be delivered to and withheld from the apparatus under control.

In the operation of this interrupter, the plug 1 is connected to any suitable source of alternating current and the switch 2 is closed, thereby energizing the transformer 3' and causing current to energize the filaments of the tubes 7 and 8, heating the cathodes to the proper temperature for tube operation. At the same time bias voltage is applied to control grid 28 of the tube 8 from said transformer through potentiometer H, relay contact 213 and grid resistor 35. This voltage is out of phase by 180 with the plate voltage of tube 8, said plate voltage being applied to the plate of tube 8 through relay coil and switch it, when this switch is closed. Since the grid of the tube 8 is negative with respect to the adjacent cathode of said tube, when the plate voltage is positive with respect to said cathode, the tube cannot pass current through the relay coil, and the relay remains deenergized. Current however can flow through relay contact i6, tube 1, variable resistances 2i and 22, switch and condenser 23, permitting a positive charge to build up in said condenser, the duration of such charge depending upon the setting of the variable resistances 2| and 22 and switch 25. This positive voltage from the condenser is applied to the grid of tube 8 through resistance 27, and when the magnitude of the positive voltage is sufficient to cancel out or offset the negative voltage being applied to the grid of said tube, the tube passes current from its cathode 48 to its plate, said current flowing through the relay coil and energizing the relay, which operates to change the setting of the respective contacts. During the period just described, the controlled apparatus connected to the terminals 42 and 44 has been off, asit has due to relay contactllhav received no current 20 connects resistances 33 and 3i in series across 7 the voltage supply potentiometer l i, and decreases the negative voltage applied to the grid of tube 8 through resistance 35. 'Ihe closing of contact [8 places variable resistances 2e and 3!, fixed resistance 30 and switch 33 across or in shunt with condenser 23, permitting the positive voltage in said condenser to discharge the length of time required, depending upon the setting of the variable resistances 29 and SI and switch 33. This is possible since closing of the relay has also opened contact l6, stopping the flow of current through tube 1, said current having been previously employed to charge said condenser. As the positive voltage in said condenser leaks oif'through the variable resistances 39 and 3| and fixed resistance as and switch 33, the potential of the voltage drops, and the positive voltage delivered to the grid of said tube likewise drops, and the positive voltage will in a given time reach a point where it becomes less than the negative voltage passing through the resistance 35, and when this condition is reached the tubes grid again becomes negative and the tube stops firing or passing current through the relay, so that the latter then opens. This restores the contacts to their original positions and the cycle of operation is repeated.

Potentiometer M is employed to adjust the bias voltage delivered to tube 8, so that when switch 25 is opened and variable resistances 2| and 22 are set at maximum, a period of approximately one minute will elapse before the positive voltage in condenser 23 attains such magnitude as to cause current to flow in said tube and close said relay. Potentiometer 31 is employed to adjust the bias voltage delivered to said tube, so that when the switch 33 is open and variable resistances 29 and 3! are set at maximum, a period of about one minute will elapse before the positive voltage in the condenser reaches the minimum necessary to allow the negative voltage on the rent.

In the foregoing description there has been described an embodiment of the invention which gives a very wide range of period Variations, but for those'cases or installations in which a substantially narrower range will sufiice, a modification embodying the same principle of operation comprises the elimination of resistance I! and adjustable contact I2, and the direct connection of wire 38 to the free end of winding 5 ii; omission of the secondary winding 5, if desired, and substitution of batteries or other source of current for heating the tube filaments 5 and 6, which substitution as a matter of fact can be employed in either form of the device; and omission of variable resistance 2!, switch 25, variable resistance 28, fixed resistance 33 and switch 33. Also relay contact 13 maybe omitted and the two wires leading thereto on the drawing permanently connected together. On the other hand, by adding an additional contact to said relay between wire l3 and a third terminal (not shown), an additional output will be provided which will permit a second light, or other type of electrical device, to be energized alternately with whatever device may be connected to terminals 42 and tube to stop the tube from passing cure 44. Furthermore, an additional contact can be added connected with two additional terminals, so that another apparatus having its own independent power supply can be turned on and ofi by the operation of the device herein described. This modification is shown in Fig. 2.

Having thus described my invention, what I claim and desire to protect by Letters Patent of the United States is:

An electronic interrupter, comprising a rectifier tube and a thyratron tube, an auto-transformer having a two-section primary and a secondary, the filaments of said tubes being heated from said secondary, one section of said primary being connected to a source of alternating current and the other section being connected to one side of said current source through an adjustable resistance, a relay connected to said source and having a normally closed contact controlling the passage of current from said source to the plate of said rectifier tube, a second contact normally open and controlling the passage of current from said source to a discharge terminal, the cathode of said rectifier tube being connected through a pair of variable resistances in series, the second resistance being provided with a switch-controlled shunt, and a condenser connected with the first-mentioned current source, the rectifier side of said condenser being connected through a normally open relay contact, a variable resistance, a fixed resistance and a switch-shunted switch to the opposite side of said condenser, the rectifier side of said condenser being also connected through a fixed resistance to the control grid of said thyratron tube and through a fixed resistance and a Variable resistance to an adjustable contact on said auto-transformer resistance, said last-mentioned adjustable resistance being shunted by a normally closed relay contact, the connection between said last-mentioned pair of fixed and variable resistances being connected through a normally open relay contact and another fixed resistance with the second-"mentioned section of said transformer and current source, and the suppressor grid and cathode of said thyratron tube being connected to a second discharge terminal and one side of said current source.

WALTER P. MENKHAUS.

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

UNITED STATES PATENTS Number Name Date 1,939,609 Minkler Dec. 12, 1933 2,003,992 Cockrell June 4, 1935 2,047,127 Huber July '7, 1936 2,473,344 McCown June 14, 1949 2,478,279 Kochenburger Aug. 9, 1949

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