US2496486A - Electronic control for electrically operated devices - Google Patents

Description

3nventor, iferfkfleizfifia ug attorney MENKHAUS ELECTRONIC CONTROL FOR ELECTRICALLY OPERATED DEVICES Filed Jan. 23, 1948 Feb 7, 1950 Patented Feb. 7, 1950 UNITED STATES PATENT OFFICE ELECTRONIC CONTROL FOR- ELECTRICALLY I OPERATED DEVICES Walter P. Menkhaus, Philadelphia, Pa.

Application January 23, 1948, Serial No. 3,888 a (01, 171-4)?) 4 6 Claims. 1

The object of the invention is to provide improvements in electronic controls or interrupters especially designed for the operation of intermittent electric signs, beacons, traffic control signals and in fact every conceivable electrically controlled device or mechanism, that is intended to be alternately energized or actuated in periodic sequence, this application covering an improvement over the disclosure. of copending application Serial No. 718,863, filed December 2'7,

-More particularly, an object of the invention is to provide a control of this type, which possesses a combination of functions, one of which is to control the operation of intermittent test apparatus, flash signs such as are used for advertising, warning and similar. purposes characterized by periods of energizing and deenergizing two dilferent circuits whether-of the same or different duration, while the other function is to simultaneously, yet independently of the first, operate a progressive set of circuits such as the minimum of three groups of lamps in a border that when energized in a predetermined sequence create appearance of a travelling or progressive effect, such for example as a scintillating or rip pling border of a sign. I I

A furtherobject is to provide a completely automatic device of this class,'which wholly eliminates the necessity heretofore of employing a motor and commutator combination, which are usually limited to a singlepredetermined periodic control, such as can be altered only by changing the design of the commutator and/or the speed of the motor.

And a still further object is to provide a device of this character, which experiences but little depreciation through wear and tear, and in which substantially the only replacement involvedis when the tubes burn out or a relay contact requires cleaning, and such similarly relatively insignificant details.

Reference to the accompanying wiring diagram indicates better than a detailed description how the several elements are inter-connected, each of said elements being identified by standard nomenclature, while three of the variable resistances are'shown as being connected by rel-'' atively heavy broken lines, to indicate that they are preferably oscillated angularly in unison, as I delivering about -120 volts which is widely standard. The switch. 2' is closed, thereby energizing the primary of the transformer 3 and causing current from the smaller undivided transformer secondary 3b to energize the filaments of the tubes 2|, 38 and 5| at full voltage and of tube 4 at a lower voltage, due to the action of the resistor 5, which is between the tube 4 and said transformer. secondary. This prevents tube 4 from reaching operating temperature until after tubes 2|, 38 and 5| have reached their proper temperaturesand are ready to function. At the same time bias voltage from. the larger transformer secondary 3a is applied to the control grid of tube 2| through resistors 6 and M, to the control grid of tube 38 through resistors 24 and 25, and the control gridof tube 5| through resistor 42. This voltage is out of phase with the plate voltage of said tubes 2|, 38 and 5|, said plate voltage being supplied to tube.2| through relay coil 26, tube 38 through relay coil 29, and to tube 5| through relay coil 44, said plate voltage being supplied to tubes as long as power is suppliedto device, whether tubes are conducting or not conducting.

Since the control grids of said tubes 2|, 38 and 5| are negative with respect to the cathodes of said tubes when their plates are positive with respect to the cathodes of said tubes, the tubes can not pass current through their respective relay coils, and the coils consequently remain deenergized. Current, however, can flow through tube 4, relay contact [3, variable resistor l and into condenser 8, permitting a positive charge to build up in said condenser, the duration of the charging time being dependent upon the setting of variable resistor I. This positive charge is app-lied to the control grid of tube 2| through resistor l5, and when the magnitude of this positive charge or voltageis sufficient to cancel out,

4 or offset, the negative voltage being applied to the grid of said tube through resistors 6 and M, the tube passes current from its cathode to its plate, said current flowing through the relay coil 26 and energizing the relay, which operates to change the setting of its respective contacts. During the period thus described, the portion of the sign or other device being controlled through its connection to output receptacle it was re ceiving no current, due to its relay contact 9 being open, while that portion of the sign or the like being controlled through its connection to output receptacle I! was receiving current for its operation due to said relay contact It being closed.

When tube 2| passes current through relay coil 26, causing it to operate that portion of the sign connected to outlet It, said sign receives current due to closing of contact 9, while the other portion of the sign connected to outlet receives no current, due to the opening of the contact |0, at the same time relay contacts I and I2 close and relay contact |3 opens. The opening of contact |3 arrests the flow of current to said condenser 8, which current it had received from tube 4, and permits the positive charge in said condenser to leak oil through contact 2 (now closed), fixed resistor l9 and variable resistor 20. The duration of time required for the charge to leak off depends upon the setting of the variable resistor 20. At the same time closing of contact H has connected resistance |8 in series with resistance 6 and reduced the negative voltage applied to the control grid of tube 2| through resistance l4. When the positive voltage delivered from condenser 8 through resistor I reaches a point wher it is less than the negative voltage applied through resistance l4, the grid of tube 2| will again be negative with respect to its cathode, and the tube will stop firing or passing current from its cathode to its plate, and the relay coil will become deenergized. This will restore the contacts to their original positions and the cycle of operation will be repeated. This arrangement provides two outlets l6 and H, which accordingly deliver current consecutively or alternately, the time duration of either of which can be separately controlled.

During the cycle of operation just described, and independently thereof, current has been flowing from tube 4, through relay contact 35, variable resistor 28 and condenser 39, permitting a positive charge to build up in condenser 39, the duration of the charging time depending upon the setting of the variable resistor 28. This positive charge is applied to the control grid of tube 38 through the resistor 21, and when the magnitude of this positive charge or voltage is suflicient to cancel out, or offset, the negative voltage being applied to the grid of said tube through resistors 24 and 25, the tube passes current from its cathode to its plate, the current flowing through the relay coil 29 and energizing the relay, which thereby operates to change the setting of its respective contacts. During this period, that portion of the sign or the like connected to the outlet receptacle 48 has been receiving current for its operation through contact 3| which has been closed. At the same time, those portions of the sign connected to outlet receptacles 49 and 50 have been receiving no current, due to contacts 45 and 30 being open. Also, at the time of energizing the relay coil 29, contacts 32 and open and contacts 33 and 34 close.

Opening of contact 35 arrests the flow of current from tube 4 through variable resistor 28 and condenser 39. This stops the accumulation of a positive charge in condenser 39. The closing of contact 33 connects resistor 36 in series with resistor 24 and lowers the negative voltage applied to the control grid of tube 38 through resistor 25. The closing of contact 34 permits current to fiow from tube 4 through variable resistor 40 and condenser 4|, permitting a positive charge to accumulate in condenser 4|, the duration of the charging time depending upon the setting of variable resistor 40. This charge is applied to the control grid of tube 5| through resistor 43, and when the magnitude of said charge or voltage is sumcient to cancel out or offset the negative voltage being applied to the control grid of said tube through resistor 42, the tube passes current from its cathode to its plate. said current flowing through relay coil 44 and energizing the relay, which operates to change the setting of its several contacts.

During the period just covered, that portion of the sign connected to outlet receptacle 59 has been receiving current through contacts 46 and .30, which have been closed. At the same time,

that portion of the sign connected to outlets 48 and 49 have been receiving no current, due to contacts 3| and being open. Likewise, tube 38 has been firing or passing current continuously during the same period. At the time of energizing relaycoil 44, contact 41 closes and connects variable resistor 53 in parallel with condenser 39. This permits the positive charge or voltage in condenser 39 to leak off and the magnitude of the voltage applied to the control grid of tube 38 through resistor 21 decreases "and will in a given time, depending upon the setting of the variable resistor 53, reach a point where it becomes less than the negative voltage applied through resistor 25, and when this condition is reached the tubes grid again becomes negative, and it ceases to pass current. This restores the contacts 30, 3|, 32, 33, 34 and 35 to their original positions.

The return of contact 32 to its original position places resistor 23 in'parallel with condenser 4|, discharging it rapidly so that the positive charge across it is no longer applied to the control grid of tube 5| through resistor 43, and said grid thereupon becomes negative with respect to its cathode due to the negative voltage being applied through resistor 42, causing the tube to stop passing current through'relay coil 44, and

, contacts 45, 46 and 41 are at the same time re stored to their original positions. During this period, that portion of the sign or the like connected to outlet 49 has'been receiving'current for its operation as the result of contacts and 39 having been closed, while portions of the sign connected to outlets 50 and 48 have been receiving no current, due to contacts 45 and 3| being open. Also, at the end of this period, the contacts of both relays have been restored to their original settings and the cycle of operation is repeated. t l 1 This wiring arrangement provides the three outlets 48. 49 and 50, which from their positions in the circuit permit the connection thereto of the same number of lamps'lor other elements or groups of elements intended 'to operate in sequence), with the result that these last-mew tioned lamps or elements whether single or in multiple recurrent arrangement'as in a border; will be illuminated in one, two, three sequences for as long as may be desired. The duration of each energizing or illumination may be either relatively instantaneous or for a more prolonged period, but if of relatively short duration the efifect in a border will be to make sa' border appear to travel continuously inone direction,

either fast or slow. The period of illumination can be controlled either simultaneously by coupling the three variable resistor 28/ 40; and531 together, as indicated by the clotted/lines, or independently of one another if preferred, thus From the foregoing. it will apparent that;

an electronic control of 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 condensers, tubes, resistances, relays, etc., while it is recognized that at this time the principles of internal electric operation may not be fully understood.

Condensers 22, 31 and 52 are not essential to operation of the control, but are present and used in order to prevent the emission of radio frequency waves, having a step wave front, which would otherwise be likely to cause interference (so-called man-made static) in radio receivers located in the immediate vicinity of the control. Consequently, these last-mentioned condensers may be omitted without interfering with the operation of the control, as it performs its intended functions.

When variable resistances 28, 40, and 53 are connected together mechanically for simultaneous operation, it may be necessary to connect one or more additional resistors, not shown, in parallel or across one or more of said variable resistances to equalize the time of which current or power is delivered to channels 48, 49 and 50, due to variations in values of various parts used.

In the specification and claims, the terms firing, passing current, or conducting, when referring to a thyratron means that the thyratron is passing current from its cathode to its plate on the positive half of the plate voltage cycle and not firing, stops firing, or not conducting, means that the thyratron is not passing current from its cathode to its plate on the positive half of the plate voltage cycle. The name Thyratron refers to a grid-controlled rectifier tube of the mercury vapor vacuum type.

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

1. An electronic control for controlling electrically operated devices, comprising a rectifier tube and three thyratron, grid-controlled rectifier tubes, a potential transformer having a primary and two secondaries one of which is split, said primary being connected to a source of alternating current, the filaments of said tubes being heated from the misplit secondary, the tape of the split secondary being connected to one side of the current source and to the cathode of each of the said three thyratron tubes, said cathodes being also connected to the suppressor grids of said tubes, one side of said split secondary being connected to the plate of said rectifier tube while the other side of said split secondary is connected to the grid of said thyratron tubes through resistances, three relays connected to said current source and actuated by the respective thyratron tubes, each of said relays having normally open and normally closed contacts for controlling current discharge terminals, a condenser connected through a variable resistance and a normally closed contact of one of said relays to the cathode of said rectifier tube, said condenser also being connected to one of said thyratron tubes through a resistance, said condenser also being connected through a second normally open relay contact and through a fixed resistor and a variable resistor to the cathode of said last-mentioned thyratron tube, a third normally open contact of said relay being connected between the cathode of said lastmentioned thyratron tube, a resistance and the end of said split transformer secondary, the other side of said condenser being connected to the cathode of said last-mentioned thyratron tube, a

second condenser connected through a variable resistance and normally closed'contact on a second relay. to the cathode of said rectifier tube, said last-mentionedcondenser also being con-.- nected to a second thyratron tube through a resistance, and said last-mentioned condenser also being connected through a normally open contact of the third relay and a variable resistance to the cathode of said second thyratron tube, a second normally open contact on said second relay being connected between the cathode of said second thyratron tube, a resistance and the end of said split transformer secondary, while the other side of said second condenser is connected to the oathode of said second thyratron tube, a third condenser connected through a variable resistance and a normally open contact on said second relay to the cathode of said rectified tube, said lastmentioned condenser also being connected to the third thyratron tube through a resistance, said last-mentioned condenser also being connected through a normally closed contact on the second relay to the cathode of said third thyratron tube.

2. A device constructed in accordance with claim 1, in which altering of at least one variable resistor varies the length of time current is applied to one pair of said terminals, and variation of three of the remaining variable resistors varies the length of time which current is applied in sequence to the corresponding three pairs of said terminals independently of said first-mentioned pair of terminals.

3. In a device of the class described, the combination of a thyratron tube, means to supply current thereto, electrical means by which the opening and closing of the contacts of a relay in the plate circuit causes changes in the voltages applied to the control grid of said tube, thereby causing said tube to start and stop conducting alternately and continuously as long as power is applied to the device, control means whereb the length of time the tube is conducting or not conductin can be regulated independently, and means whereby powercan be delivered to output terminals alternately and continuously for the identical length of time as the said tube is conducting or not conducting current.

4. A device according to claim 3, wherein power means are provided for a thyratron having its cathode connected to one side of the power source and its plate connected to the opposite side of said source through a relay coil, and wherein means are provided whereby the opening and closing of the contacts of the relay changes the voltages applied to the control grid of said tube causing said tube to become conductive and non-conductive alternately and continuously, and means to control the periods of conduction and non-conduction of said tube.

5. A device of the class described, wherein first and second thyratron tubes are connected so that the opening and closing of contacts of a relay in the plate circuit of one of said tubes causes changes in the Voltages applied to the control grid of the second of said tubes, to cause said second tube to start and stop conducting, which through the opening and closing of contac s of a relay in the plate circuit of said second tube causes changes in the voltage applied to the control grid of said first tube, thereby causing it to start and stop conducting, said tubes starting and stopping conduction alternately and continuously as long as power is applied to the device, means whereby power can be delivered to the output terminals alternately and continuously for the operation of the relay by the thyi'atron changes the voltages applied to the control grids of said tubes, causing said tubes to start and stop conducting, the starting and stopping of the conduction being alternate and continuous, means whereby the relay can control its own thyratron or another succeeding thyratron tube, and means whereby the length of the periods of conduction and non-conduction can be controlled independ- 10 ently of or simultaneously with one another.

WALTER P. MENKHAUS.

No references cited.

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