US2297740A - Voltage-regulating equipment for precipitators or the like - Google Patents

Description

Oct. 6, 1942. M. J. BROWN VOLTAGE-REGULATING EQUIPMENT FOR PRECIPITATORS OR THE LIKE Filed Oct. 26, 1940 WITNESSES: INVENTOR 5 4. p I -Myr anf5rorvn.

ATTORNEY Patented 013.6, 1942 VOLTAGE-REGULATING EQUIPMENT FOR PRECIPITATORS OR THE LIKE Myron J. Brown, Wilkinsburg, Pa., assignor to Westinghouse Electric .2 Manufacturing Company, East Pittsburgh, Pa., a corporation of Pennsylvania.

Application October 26, 1940, Serial No. 362,944

16 Claims.

My invention relates to novel current-responsive means and novel voltage-regulating means for electrostatic smoke-precipitators or other electrical load-devices having a certain desirable operating-range in which transient flashes or current-increases occur at a certain predetermined rate at the highest safe operating-voltage which should be applied to the load-device,

The efliciency of an electrostatic precipitator depends upon its applied-voltage; and the amount of voltage which can feasibly be applied to the precipitator is limited by the tendency of the precipitator to are over, or to become shortcircuited by means of a. concentrated-current are which hangs on until the precipitator-voltage is suitably reduced. In some precipitator-installations, particularly where rather high ballastresistances are utilized in series with the circuit, and where fairly high arc-extinguishing draftvelocities of the treated gases are utilized, it has been found that there is an operating-range, at voltages just short of the voltage which will produce series arcing, in which the precipitator will exhibit the phenomenon of spitting or flashing or flashovers, resulting in momentary or tran sient current-increases which do not hang on, like an arc-current, but which heal themselves and return again to normal-current conditions, the frequency and intensity of such spitting increasing as the applied-voltage approaches closer and closer to the voltage at which arcing occurs.

It should be understood that both the flashovers and the arcings of the precipitator are random phenomena, occurring at widely variant intervals even under seemingly identical conditions, and of course varying with the nature and size of the smoke-particles or other foreign matter contained in the draft of gases passing through the precipitator, and also varying from other causes. Because of the random nature of the spitting phenomenon, it is necessary, in order to keep the precipitator operating at its highest permissible voltage, to reduce the applied voltage whenever the frequency or intensity of the spitting-impulses becomes too high, and to keep increasing the voltage, so as to slowly advance it toward a higher value, whenever the rate of occurrence of the spittings falls off below a predetermined number of spittings in any suitable t me-interval.

In many electrical smoke-precipitator applicat ons, the maximum permissible precipitatingvoltage which will not produce arcing, or too f equent arcing or short-circuiting of the precipitator, is variable from time to time, depending upon a number of factors, including the cleanness of the precipitator, the atmospheric conditions, and the smoke conditions. In order that the precipitating equipment may always be operated at its highest permissible voltage, and

hence at its maximum efliciency, it is frequently desirable to provide means for automatically varying the voltage which is applied to the precipitator so as to produce harmless momentary or transient fia'shings at a predetermined average rate which experience has shown to be feasible, the procedure being to keep raising and lowering the precipitator-voltage as may be necessary to maintain the rate of flashing within prescribed limits. My invention relates to novel and improved means for accomplishing such a purpose.

The objects of my invention also include certain specific means and combinations, including (1) the use of a slowly moving timing-device or relay, having front and back contacts, and having a drifting rate of movement, in their direction, which is substantially independent of the electrical conditions of the precipitator, or the amount of precipitator-current, whenever the timing-device is moving at all, (2) specifically the use of a line-energized slow-type voltagerelay for the above-described timing device, (3) the use of current-responsive means which responds to instantaneous or momentary values of the magnitude of the current, regardless of the rate of change of the current as in some previous devices, (4) and specifically the use of a cold-cathode grid-glow tube with its grid energized responsively to the precipitator-current, as the specific current-responsive means referred to.

With the foregoing and other objects in view, my invention consists in the apparatus, systems, combinations, methods and parts hereinafter described and claimed, and illustrated in the accompanying drawing, wherein:

Figure l is a diagrammatic view of the essential features of an electrostatic precipitatorequipment embodying my invention in a simple form of embodiment for illustrating the essential principles of the invention, without the distraction of numerous details which are known to the skilled workers of the art and which do not constitute any essential part of my present improvements; and

Fig. 2 is a diagrammatic view of a portion of the circuit, illustrating a modification.

In Fig. 1, my invention is. illustrated as being applied to the control of an electrostatic precipitator which is diagrammatically represented as comprising a grounded conducting duct or chimney 3, through which passes one or more precipitating-wires or electrodes 4, which are energized, through a mechanical, rotating rectifier 5, from the high-voltage secondary-winding 6 of a step-up transformer 1. The primary winding 3 of the precipitator-transformer 'l is connected to a supply-circuit 9 which is energized from a single-phase supply line Ll-L2 through a ballast-resistor H and a voltage regulating means which is illustrated in the form of an inductionregulator l2 which is adjusted, either in 9. voltage-raising direction or in a voltage-lowering direction, by means of an alternating-current motor M having a raising winding RW and a lowering-winding LW.

The energization of the regulator-motor M, in either the raising or lowering direction, is under the control of a timing-means having a fairly constant timing-interval which is substantially independent of the operating-conditions of the preclpitator, such timing-means being illustrated in the form of a slow-moving voltage-relay V such as a contact-making instrument of the induction-disc type, having back-contacts I5 and front or make contacts It. The voltage-relay V has biasing-means, illustrated in the form of a spring i7, tending to return the movable contact-element It to its non-actuated position in engagement with the back-contacts l5, and it is also provided with an actuating-coil l9 which, when sufllciently electrically energized, so that its operating-force overpowers the pull of the biasing spring 5 7, causes the movable element i 3 to slowly move to its actuated position in engagement with the front-contacts it. The actuatingcoil l3 of the voltage-relay V is energized from the line Ll-L2, through a variable resistor 2d by means of which the operating-speed or forward-moving speed of the voltage-relay may be adjusted.

Suitable means are provided for causing the biasing-action oi the biasing spring 57 to predominate over the actuating-force of the electrically energized coil It at certain times, as will be subsequently described. The illustrated means for causing the biasing spring to predominate includes a short-circuiting circuit 2! around said actuating-coil I9, said short-circuiting circuit including a variable resistor 22 for adjusting the resetting speed or backwardly moving speed of the voltage-relay V. The short-circuiting circuit 2!, around the actuating-coil E9 of the voltagerelay V, is completed by the closure of either one of two relay- contacts 23 or 23, as will be subsequently described.

In order to avoid the necessity for utilizing voltage-relay contacts i5 and it which are sufllciently heavy to control the regulator-motor M, I have shown, as a matter of practical convenience, the utilization of two auxiliary relays 25 and 26 which are respectively energized from the back and front-contacts l5 and l 5 of the voltagerelay V. The auxiliary relay 25 is a voltagelowering relay having a make-contact 21 which is utilized to energize the lowering-winding LW of the regulator-motor M. The auxiliary relay 28 is a voltage-raising relay having a make contact 28 which is utilized to energize the raisingwinding RW of the regulator-motor M. A capacitor 29 is connected across the terminals of the two motor-windings LW and RW to obtain reversing operation with a single-phase motor, in a manner which is known in the art.

The voltage-raising relay 26 also carries the normally open contact 24 which is utilized for the purpose of completing the short-circuiting circuit 2 22 around the operating-coil IQ of the voltage-relay V. The object of this relaycontact 24 is merely to reduce the speed at which the voltage of the induction-regulator I2 i increased, this result being accomplished by "inching the regulator-motor M in the voltage-raising direction, instead of continuously energizing the voltage-raising winding RW thereof and letting the motor run continuously as long as the voltage-relay front-contact I6 is closed. This regulator-inching means, in the form of an antihunting contact 24, is a known feature in the art, and is illustrated only because it is usually, though perhaps not universally, desirable, provided that the regulator-voltage is not raised too fast.

In order to cause the voltage-relay V to reset, or to move in the backward direction under the influence of the biasing spring ill, it is necessary to provide some means for closing the relay-contact 23 and keeping it closed for a sufllciently long time or times to permit the movable contactelement 18 of the voltage-relay to drift back from its front-contact position It to its back-contact position it. I have provided a novel means for efiecting this purpose, utilizing a cold-cathode grid-glow tube 3! having an anode 32, a grid 33 and a cathode 36. This tube or space-current arcing-device 3! has the property of "breaking down" or glowing or becoming conductive or areing across its anode-cathode space, only when the starting control means or grid 33 is made sufilciently positive with respect to the cathode M, for any given anode-cathode applied-voltage within the voltage-rating of the tube, and the tube has the further property, once it has broken down by the glowing of the grid, of maintaining its glowing or arcing or conducting condition, independently of the subsequent condition of said starting control means, until the applied voltage is interrupted or very materially reduced by some external or extraneous means.

In order to utilize this self locking or current- 'maintainlng property of the grid-glow-tube 3!, I

provide a suitable direct-current or unidirectional-current energizing-source in the anode-cathode circuit thereof, said source being illustrated in the form of a full-wave rectifier or rectifierbridge 36 having one diagonal energized across the alternating-current supply-line Ll-L2, so that the other diagonal of the bridge constitutes the direct-current terminals and The direct-current output-terminals and of the rectifier-bridge 36 are shunted by a bypassing capacitor 3? for the purpose of smoothing the direct-current voltage. The anode-cathode circuit of the grid-glow tube 3| includes the operating coil 38 and a back-contact 39 of a short-time relay 4|, said anode-cathode circuit being traceable from the positive terminal through the coil 38 and the contact 39 to the anode, 32, and thence from the cathode 34 to the negative terminal The short-time relay 4|, in addition to carrying the back-contact 39, also preferably carries a second back-contact 42, and also the previously described make or front-contact 23 which shortcircuits the operating-coil 59 of the voltage-relay V through the adjusting resistor 22 whenever the short-time relay 4| is in its actuated position. The second back-contact 42 of the short-time relay 4| is utilized to energize a bypassing capacitor 43 in shunt-circuit relation to the operatingwinding 38 of said relay, with the result that,

when the grid-glow tube 3| breaks down or begins to glow and conduct current in its anodecathode circuit, the first current which flows is utilized to charge the capacitor 43. At the first instant, the capacitor 43 takes all of the tubecurrent, none of it passing through the highly inductive relay-coil 38. The capacitor 43 charges at a predetermined rate limited by the amount of current which is supplied thereto through the rectifier-bridge 36 and the grid-glow tube 3|, and as said capacitor 43 charges, its short-circuiting effect upon the relay-winding 38 becomes smaller, so that the current is transferred to the relay-coil 38, thus finally causing the shorttime relay 4| to 'pick up or move to its actuated position in which it opens its back- contacts 39 and 42 and closes its front-contact 23.

The two back- contacts 39 and 42 of the short time relay 4| are bypassed by an adjustable resistor 44 in such manner that when the relay 4| is actuated, the back- contacts 39 and 42 being open, the variable resistor 4| is included in a capacitor-discharging circuit whereby the capacitor 43 discharges throughsaid adjustable resistor 44 and the actuating-coil 38 of the short-time relay 4|, the discharging-rate being controllable by adjusting the resistance 44. By this means, the energization of the short-time relay 4| is maintained for a certain brief time-interval after the actuation of the relay, thus maintaining said relay in its actuated condition for a short timeinterval which, in general, is or may be somewhat longer than the time-delay which was introduced in the picking-up operation of the relay while the cap-acitor 43 was initially charging. The size of the capacitor 43 is usually chosen so that it will store enough current to keep the relay-coil 38 energized for an appreciable timeinterval, and during this time, the front-contact 23 of the relay remains closed, so that the movable contact |8 of the voltage-relay V is drifting backward in its resetting direction, or toward its back-contact |5.

The initial breaking down or glowing of the grid-glow tube 3| is adjustably controlled in response to the current flowing in the alternatingcurrent supply-circuit 9 of the precipitator. To this end, I have shown an ordinary currenttransformer 46 in said supply-circuit 9, said current-transformer being utilized to energize a high-voltage or step-up transformer 41, which is loaded by means of a resistor 48 which thus develops a voltage-drop or potential which is proportional to the supply-circuit current. The

resistor 48 is included in the grid-circuit of the grid-glow tube 3|, said grid-circuit also serially including a high-resistance grid-resistor 49, and an adjustable potentiometer The terminals of the potentiometer 5| are connected across the direct-current supply-circuit terminals and and an adjustable intermediate tap 52 of said potentiometer is included in the grid-circuit. The grid-circut may thus be traced from the grid 33 of the grid-glow tube 3| through the resistors 49 and 48 to the adjustable intermediate potentiometer-tap 52, and thence through a portion of the potentiometer 5| to the negative source-terminal which is also connected to the cathode 34 of the grid-glow tube 3|.

In operation, the voltage-relay V is normally energized so that said relay picks up and closes its front or make-contact l6, thus energizing the voltage-raising relay 25 and causing the regulator-motor M to inch" along in the voltage-raising direction, thus gradually or cautiously raising the voltage applied to the precipitator 4. As the precipitator-voltage rises higher and higher, the

frequency and the intensity of its spitting-operations increase. Whenever such spitting occurs, the supply-line current in the current-transformer 46 also increases, and when a sufliciently severe momentary or instantaneous current-value is obtained during a positive half-cycle, that is, during a half-cycle of the alternating-current supply during which a positive voltage-component is applied to the grid 33 by the resistor 48, this voltage-component, when added to the tapped voltage of the potentiometer 5|, will exceed the critical starting-voltage of the gridglow tube 3|, causing a glow-discharge to occur between the grid 33 and the cathode 34, said glow-discharge immediately filling the tube so that the anode-cathode tube-circuit or space is broken down or made conductive by means of a glow-discharge between the anode 32 and the cathode 34. The relay-bypassing capacitor 43 then charges, and as it approaches its chargedcondition, the current passing through the gridglow tube 3| transfers to the operating-coll 38 of the short-time relay 4|, causing said short-time relay 4| to pick up, opening its back- contacts 39 and 42, the closing its front-contact 23.

The closure of the relay-contact 23 short-circuits or bypasses the operating-coil I! of the voltage-relay V, causing the latter to drift toward its non-actuated position, first immediately or quickly opening its front-contacts I6, thus stopping the forward or voltage-raising movement of the induction-regulator |2, after which the movable contact-member l8 of the voltagerelay slowly moves between its two limiting positions in a direction toward the voltage-lowering contact or back-contact IS.

The relay-contact 23 which causes this backward drifting of the voltage-relay V remains closed for a predetermined brief time-interval which is controlled by the discharging-rate of the relay-bypassing capacitor 43, which is now being discharged through the relay-coil 38 in series with the adjustable resistor 44. The time-interval during which the short-time relay 4| remains energized, keeping the relay-contact 23 closed, is adjustable, by means of the adjustable resistor 44. The rate at which the voltage-relay V is drifting backwardly, during this time-interval, is also adjustable, by means of the adjustable resistance 22, By either or both of these means, it is possible to adjust the amount or distance through which the voltage-relay V drifts backwardly during the time-interval during which the short-time relay 4| remains in its actuated position, and this drifting-distance is usually chosen so that it takes more than one, or several, such time-intervals to cause the movable contact |8 of the voltage-relay V to move all the way back from its fully actuated position in contact with the make-contacts Hi, to its fully retrieved position in contact with its back-contacts I5.

At the termination of the delayed-action current-responsive impulse which is provided by the short-time relay 4|, as just described, the shortcircuit is removed from around the operating-coil IQ of the voltage-relay V, so that th movable element i8 of said voltage-relay starts drifting forward again, toward its front or make-contact Hi. This forward-drifting speed is controllable by the adjustable resistor 20, and is preferably adjusted so that it is of the same order of magnitude as the backward-drifting or resettinz speed previously referred to.

If a second current-impulse of sufficient magnitude and polarity does not occur before the voltage-relay V closes its front-contacts l6, the regulator-motor M will start inching again in the voltage-raising direction, thus again slowly raising the voltage applied to the precipitator wire 4. If, however, another current-impulse occurs, so as to check the forward drifting ofthe voltage-relay V before it closes its front-contacts I6 again, said voltage-relay will start drifting backward again, through another short timeperiod under the control of the short-time relay 4!, and on this occasion the voltage-relay will drift back still further, closer to its back-contact I5, because it started to drift backwardly from an intermediate position between the two limiting contacts I and 16. When such current-responsive impulses occur at a sufiiciently fast rate, the movable element I8 of the voltage-relay V will drift all the way back to its back-contact 15, thereby energizing the voltage-lowering winding LW of the induction-regulator motor M, thus quickly reducing the voltage which is applied to the precipitator. At the termination of the last current-responsive delayed-action or short-time impulse which caused a reduction of the precipitator-.voltage, the voltage-relay V will again start to drift forward, opening its back-contact i5; and if the frequency of recurrence of the precipitatorfiashings has now been sufliciently reduced, as a result of the reduction in the precipitator-voltage, the voltage-relay V will finally drift to its full-actuated position 16, starting all over again to slowly inch the regulator-motor M in the voltage-raising direction.

While I have described my invention in connection with certain relative time-intervals and drifting-times, and while I have referred to the current-response as a series of discrete responses to transient current-impulses, I wish it to be understood that the operation of my device is not altogether limited in these respects. It is to be noted, in particular, that I have provided means whereby a wide range of adjustment is readily possible, in regard to the choice of the various timing-intervals and drifting-speeds or periods. As an example, but not by way of limitation, it may be noted that my invention can be utilized in a precipitating system under such operatingconditions as to obtain from 6 to snaps or fiashings per minute, utilizing a voltage-relay V having a drifting-time of some 20 seconds, or

between 10 seconds and seconds, for a full swinging-movement of the'movable contact-element [8 in either direction of movement, and utilizing a timing-relay 4! which has a relatively brief pick-up time, but which holds its makecontact 23 closed for a short-time interval of from 1 second to 5 seconds. These various timeintervals are indicated only by way of illustration; as my invention, in its broader aspects, is not limited thereto.

In Fig. 2, I have reproduced a portion of the circuit shown in Fig. l, for the purpose of illustrating a slight variation, the principal variation being that the current-energized resistor 48 is utilized to energize the input-diagonal of an auxiliary rectifier-bridg 54. The output-diagonal of the rectifier-bridge 54 is connected in the gridcircuit of the grid-glow tube 3| in such polarity that a positive voltage-component is always applied to the grid 33, regardless of the direction of the alternating-current flow. In this manner,

the device is caused to be responsive to currentmagnitudes of a predetermined value, regardless of whether they occur in the positive or negative half-wave of the alternating current.

In Fig. 2, I have also indicated, by way of ex ample, the inclusion of the high-voltage or stepup transformer 41' directly in the supply-circuit of the preclpitator, without the intermediary of the conventional current-transformer 56 which was shown in Fig. 1. The power-translating load-device, or relay-coil 3B, in the anode-cathode circuit of the tube 3! is broadly so indicated in Fig. 2, as well as the circuit-interrupting contact or switching-device 39 which is utilized to open the anode-cathode circuit in order to interrupt a discharge of the grid-glow tube 3i. Except as noted, the operation of the device shown in Fig. 2 is the same as that which has been outlined in connection with Fig. 1.

While I have illustrated my invention in two forms of embodiment which are at present preferred, I wish it to be understood that such illustration is only by way of illustration and not by way of limitation, and I wish it to be further understood that my illustration is in a greatly simplified form, which has been done in order to facilitate the understanding of the essential features or principles of my invention. I desire, therefore, that the appended claims shall be accorded the broadest construction consistent with their language.

I claim as my invention:

1. Voltage-regulating equipment for an electrical load-device having a desirable operatingrange in which a predetermined rate of occurrence of predetermined, randomly recurrent, transient, voltage-responsive current-increases is maintained between predetermined limits, comprising a supply-circuit for said load-device, voltage-regulating means associated with said supply-circuit, means for obtaining discrete current-responses to said transient current-increases, means for prolonging said discrete current-responses for short predetermined times, said short predetermined times being less than the longest expectable time-interval between successive transient current-increases, a timing device having two difierent operational conditions, means for normally causing said timingdevice to change from a first one of its operational conditions to its second operational condition at a first predetermined speed which is .substantially independent of the electrical conditions of said load-device, means responsive to each of said prolonged discrete current-responses for causing said timing-device to change in the opposite direction at a second predetermined speed which is substantially independent of the electrical conditions of said load-device, said first and second predetermined speeds being both so slow that said timing-device completes only a part of a complete change from one operational condition to the other during one of said short predetermined times, means for adjusting at least one of the factors determining the part of said complete change which is effected during one of said short predetermined times in at least one of the directions of change of said timingdevice, means for making a lowering adjustment of said voltage-regulating means when said timing-device reaches its first operational condition, and means for making a raising adjustment of said voltage-regulating means when said timlng-device reaches its second operational condition.

2. Voltage-regulating equipment for an electrical load-device having adesirable operatingrange in which a predetermined rate occurrence of predetermined, randomly recurrent, transient, voltage-responsive increases in the magnitude of the load-current is maintained between predetermined limits, comprising a supply-circuit for said load-device, voltage-regulating means associated with said supply-circuit, means quickly responsive to any and all increases in the magnitude of the load-current beyond a predetermined value for obtaining predetermined discrete current-responses, means for prolonging said discrete current-responses for short predetermined times, said short predetermined times being less' than the longest expectable time-interval between successive transient current-increases, a timing-device having two different operational conditions, means for normally causing said timing-device to change from a first one of'its operational conditions to its second operational condition at a first predetermined speed, means responsive to each of said prolonged discrete current-responses for causing said timing-device to change in the opposite direction at a second predetermined speed, said first and second predetermined speeds being both so slow that said timing-device completes only a part of a complete change from one operational condition to the other during one of said short predetermined times, means for adjusting at least one of the factors determining the part of said complete change which is efiected during one of said short predetermined times in at least one of the directions of change of said timingdevice, means for making a lowering adjustment of said voltage-regulating means when said timins-device reaches its first operational condition, and means for making a raising adjustment of said voltage-regulating means when said timing-device reaches its second operational condition.

3. Voltage-regulating equipment for an elec-' trical load-device subject to transient currentincreases randomly recurring at a rate and with an intensity dependent upon the voltage, comprising a supply-circuit for said load-device, voltage-regulating means associated with said supply-circuit, a timing-device having two different operational conditions, means for normally developing a first actuating-effect tending, to change said timing-device from a first one of its operational conditions to its second op erational condition at a predetermined speed which is substantially independent of the electrical conditions of said load-device, currentresponsive transient-summating means for at times counteracting said first actuating-effect and developing a second actuating-effect tending to change said timing-device in the opposite direction at a current-responsive speed which is 4. Voltage-regulating equipment for an electrical load-device subiect to transient currentincreases randomly recurring at a rate and with an intensity dependent upon the voltage, comprising a supply-circuit for said load-device, voltage-regulating means associated with said supply-circuit, means quickly responsive to any and all increases in the magnitude of the current beyond a predetermined value for obtaining predetermined discrete current-responses, shorttime means for insuring that each of said discrete current-responses shall last for at least a short predetermined time which is less than the longest expectable time-interval between successive transient current-increases, a timing-device having two different operational conditions, means for normally developing a first actuatingefi'ect tending to change said timing-device from a first one of its operational conditions to its second operational condition, current-responsive means including said short-time means for at times counteracting said first actuating-enact and developing a second actuating-eflect tending to change said timing-device in the opposite direction at a current-responsive speed which is so slow, at times, as to require a plurality of transient current-increases to occur before the timing-device is completely changed from its second operational condition to its first operational condition, means for making a lowering adjustment of said voltage-regulating means when said timing-device reaches its first operational condition, and means for making a raising adjustment of said voltage-regulating means when said timing-device reaches its second operational condition.

5. Voltage-regulating equipment for an electrical load-device subject to transient currentincreases randomly recurring at a rate and with an intensity dependent upon the voltage, comprising a supply-circuit for said load-device, voltage-regulating means associated with said supply-circuit, a cold-cathode grid-glow tube, direct-current energizing-means for its anodecathode circuit, means for developing a gridbiasing voltage responsive to the load-current of the load-device and for so applying said gridbiasing voltage to the grid of the grid-glow tube as to cause a Slow therein upon the attainment of an instantaneous current-magnitude of a predetermined value in said load-devica timingmeans responsive to the glowing oi the grid glow tube for subsequently interrupting the glowing operation thereof after a short predetermined time, a timing-device having two different operational conditions, means for normally developing a first actuating-effect tending to change said timing device from a first one of its operational conditions to its second operational condition, current-responsive means including a response to the anode-cathode circuit of said grid-glow tube for at times counteracting said first actuatingefiect and developing a second actuating-effect tending to change said timing-device in the opposite direction at a current-responsive speed which is so slow, at times, as to require a plurality of transient current-increases to occur before the timing-device is completely changed from its second operational condition to its first operational condition, means for making a lowering adjustment of said voltage-regulating means when said timing-device reaches its first operational condition, and means for making a raising adjustment of said voltage-regulating means when said timing-device reaches its second operational condition. I

6. Voltage-regulatingequipment for an ielectrical load-device having a desirable operatingrange in which a predetermined rate of "occurrence of predetermined, randomly recurrent, transient, voltage-responsive increases in the magnitude of the load-current is maintained between predetermined limits, comprising a supplycircuit for said load-device, voltage-regulating means associated with said supply-circuit, a coldcathode grid-glow tube, direct-current energizing-means for its anode-cathode circuit, means for developing a grid-biasing voltage responsive to the load-current of the load-device and for so applying said grid-biasing voltage to the grid of the grid-glow tube as to cause a glow therein upon the attainment of an instantaneous current-magnitude of a predetermined value in said load-device, timing-means responsive to the glowing of the grid-glow tube for subsequently interrupting the glowing operation thereof, a timing-devicehaving two difierent operational conditions, means for normally developing a first actuatingeflect tending to change said timing-device from a first one of its operational conditions to its second operational condition, means responsive to the glowing operation of the grid-glow tube for counteracting said first actuating-efiect and developing a second actuating-effect tending to change said timing-device in the opposite direction, means for making a lowering adjustment of said voltage-regulating means when said timing-device reaches its first operational condition, and means for making a raising adjustment of said voltage-regulating means when said timing-device reaches its second operational condition. I

7. Voltage-regulating equipment for an electrical load-device having a desirable operating" range in which a predetermined rate of occurvoltage-regulating means when said timing device reaches its second operational condition.

8. Voltage-regulating equipment for an electrical load-device having a desirable operatingrange in which a predetermined rate of occurrence of predetermined, randomly recurrent, transient, voltage-responsive current-increases is maintained between predetermined limits, comprising a supply-circuit for said load-device,

voltage-regulating means associated with said supply-circuit, means for obtaining discrete current-responses to said transient current-increases, means for prolonging said discrete current-responses for short predetermined times, said short predetermined times being less than the longest expectable time-interval between successive transient current-increases, a timing-relay having an actuating-coil and a biasing-means opposing the actuating-force produced by said actuating-coil, means for electrically energizing said actuating-coil from across said supply-circuit with an amount of energization which normally causes the actuating-force of the coil to rence of predetermined, randomly recurrent,

transient, voltage-responsive increases in the magnitude of the load-current is maintained between predetermined limits, comprising a supplycircuit for said load-device, voltage-regulating means associated with said supply-circuit, a coldcathode grid-glow tube, direct-current energizing-means for its anode-cathode circuit, means for providingan independently variable unidirectional grid-biasing voltage, means for developing a grid-biasing voltage responsive to the load-current of the load-device, circuit-means for serially combining both of said grid-biasing voltages and for so applying the resultant voltage to thegrid of the grid-glow tube as to cause a glow therein upon the attainment of an instantaneous currentmagnitude of a predetermined value in said loaddevice, timing-means responsive to the glowing of the grid-glow tube for subsequently interrupting the glowing operation thereof, a timing-device having two different operational conditions, means for normally developing a first actuatingefiect tending to change said timing-device from a first one of its operational conditions to its second operational condition, means responsive to the glowing operation of the grid-glow tube for counteracting said first actuating-effect and developing a second actuating-effect tending to change said timing-device in the opposite direction, means for making a lowering adjustment of said voltage-regulating means when said timingdevice reaches its first operational condition, and means for making a raising adjustment of said predominate in such manner as to tend to cause the timing-relay to move from a non-actuated position to an actuated position at a first predetermined speed, means responsive to each of said prolonged discrete current-responses for temporarily causing the biasing-force to predominate in said timing-relay so as to tend to cause the timing-relay to move in the opposite direction at a second predetermined speed, said first and second predetermined speeds being both so slow that said timing-relay moves through only a part of the distance between its aforesaid positions during one of said shor't predetermined times, means for adjusting at least one of the factors determining the part of the distance between said positions during which said timing-relay moves during on of said short predetermined times in at least one of the directions of movement of said timing-relay, means for making a lowering adjustment of said voltage-regulating means when said timing-relay is in its non-actuated position, and means for making a raising adjustment of said voltage-regulating means when said timing-relay is in its actuated position.

9. Voltage-regulating equipment for an electrical load-device having a desirable operatingrange in which a predetermined rate of occurrence of predetermined, randomly recurrent, transient, voltage-responsive increases in the magnitude of the load-current is maintained between predetermined limits, comprising a supplycircuit for said load-device, voltage-regulating means associated with said supply-circuit, means quickly responsive to any and all increases in the magnitude of the load-current beyond a predetermined value for obtaining predetermined discrete current-responses, short-time means for insuring that each of said discrete current-responses shall last for at least a short predetermined time which is less than the longest expectable time-interval between successive transient current-increases, a timing-relay having an actuating-coil and a biasing-means opposing the actuating-force produced by said actuating-coil, means for electrically energizing said actuating-coil from across said supply-circuit with an amount of energization which normally causes the actuating-force of the coil to predominate in such manner as totend to cause the timing-relay to mov from a non-actuated position to an actuated position at a first predetermined speed, means responsive to each of said prolonged discrete current-responses for temporarily causing the biasing-force to predominate in said timing-relay so as to tend to cause the timing-relay to move in the opposite direction at a second predetermined speed, means for making a lowering adjustment of said voltageregulating means when said timing-relay is in its non-actuated position, and means for making a raising adjustment of said voltage-regulating means when said timing-relay is in its actuated position.

Voltage-regulating equipment for an electrical load-device subject to transient current-increases randomly recurring at a rate and with an intensity dependent upon the voltage, comprising a supply-circuit for said load-device, voltage-regulating means associated with said supply-circuit, a timing-relay having an actuating-coil and a biasing-means opposing the actuating-force produced by said actuating-coil, means for electrically energizing said actuating-coil from across said supply-circuit with an amount of energization which normally causes the actuating-force of the coil to predominate in such manner as to tend to cause the timing-relay to move from a nonactuated position to an actuated position at a predetermined speed, current-responsive transient-summating means for at times causing the biasing-force to predominate in said timing-relay so as to tend to cause the timing-relay to move in the opposite direction at a current-responsive speed which is so slow, at times, as to require a plurality of transient current-increases to occur before the timing-device-r'elay moves all the way from its actuated position to its non-actuated position, means for making a lowering adjustment of said voltage-regulating means when said timing-relay is in its non-actuated position, and means for making a raising adjustment of said voltage-regulating means when said timing-relay is in its actuated position.

11. Voltage-regulating equipment for an electrical load-device subject to transient currentincreases randomly recurring at a rate and with an intensity dependent upon the voltage, comprising a supply-circuit for. said load-device, voltage-regulating means associated with said supply-circuit, a timing-relay having an actuatingcoil and a biasing-means opposing the actuatingforce produced by said actuating-coil, means for electrically energizing said actuating-coil from across said supply-circuit with an amount of energization which normally causes the actuat-.

ing-force of the coil to predominate in such manner as to tend to cause the timing-relay to move from a non-actuated position to an actuated position, means responsive to the load-current of the load-device for at times causing the biasing-force to predominate in said timing-relay so as to tend to cause the timing-relay to move in the opposite direction, means for making a lowering adjustment of said voltage-regulating means when said timing-relay is in its non-actuated position, and means for making a raising adjustment of said voltage-regulating means when said timing-relay is in its actuated position.

12. Voltage-regulating equipment for an electrical load-device, comprising a supply-circuit for said load-device, voltage-regulating means asso- 'ciated with said supply-circuit, a timing-relay having an actuating-coil and a biasing-means opposing the actuating-force produced by said actuating-coil, means for electrically energizing said actuating-coil from across said supply-circuit with an amount of energization which normally causes the actuating-force of the coil to predominate in such manner as to tend to cause the timing-relay to move from a non-actuated position to an actuated position, means respon- W sive to the load-current of the load-device for at times causing the biasing-force to predominate in said timing-relay so as to tend to cause the timing-relay to move in the opposite direction, means for making a lowering adjustment of said voltage-regulating means when said timing-relay is in its non-actuated position, and means for making a raising adjustment of said voltageregulating means when said timing-relay is in its actuated position.

13. Voltage-regulating equipment for an electrical load-device subject to transient currentincreases randomly recurring at a rate and with an intensity dependent upon the voltage, comprising a supply-circuit for said load-device, voltage-regulating means associated with said supply-circuit, a cold-cathode grid-glow tube, directcurrent energizing-means for its anode-cathode circuit, means for developing transient grid-biasing voltages responsive to load-device currentincreases of a-predetermined intensity and for so applying said grid-biasing voltages to the grid of the grid-glow tube as to cause said grid-glow tube to glow, timing-means responsive to the glowing of the grid-glow tube for subsequently interrupting the glowing operation thereof, and means responsive to the glowing operation of said grid-glow tube tending to produce a lowering adjustment of said voltage-regulating means.

14. Voltage-regulating equipment for an electrical load-device subject to transient current increases randomly recurring at a rate and with an intensity dependent upon the voltage, comprising a supply-circuit for said load-device, voltage-regulating means associated with said supply-circuit, a timing-relay having an actuatingcoil and a biasing-means opposing the actuatingforce produced by said actuating-coil, means for electrically energizing said actuating-coil from across said supply-circuit with an amount 0! energization which normally causes the actuating-force of the coil to predominate in such manner as to tend to cause the timing-relay to move from a non-actuated position to an actuated position,-means for translating those transient load-device current-increases which are of a predetermined magnitude into discrete timecontrolled impulses of a predetermined magnitude and for utilizing said impulses to temporarily cause the biasing-force to predominate in said timing-relay so as to tend to cause the timing-relay to move in the opposite direction, and means responsive to the non-actuated position of said timing-relay for producing a lowering adjustment of said voltage-regulating means.

15. Voltage-regulating equipment for an electrical load-device subject to transient currentincreases randomly recurring at a rate and with an intensity dependent upon the voltage, comprising, in combination; a supply-circuit for supplying energy to said load-device; voltage-regulating means associated with said supply-circuit; a source of unidirectional potential; a spacecurrent arcing-device of a type having an anodecathode arcing-space which is normally substantially non-conducting, starting control means for initiating the conductive operation of said anodecathode arcing-space, said space-current arcingdevice being of a type in which the anode-cathode current, once started, will remain flowing, independently of the subsequent condition of said starting control means, as long as any substantial unidirectional voltage is applied to said anodecathode arcing-space; circuit-connection means for establishing a main direct-current circuit serially including said unidirectional-potential source and the anode-cathode circuit of said space-current arcing-device; means responsive to the load-current of the load-device for causing said starting control means to be operatively energized .upon the attainment of an instantaneous current-magnitude of a predetermined value in said load-device; timing-means responsive to the anode-cathode current of the spacecurrent arcing-device for subsequently interrupting the current-carrying operation thereof 'after a short predetermined time;-a timing-device having two difierent operational conditions; means for normally developing a first actuating-efiect tending to change said timing device from a first one of its operational conditions to its second operational condition; current-responsive means including a response to the anode-cathode circuit of said space-current arcing-device for at times counteracting said first actuating-effect and developing a second actuating-effect tending to change said timing-device in the opposite direction at a speed which is so slow, at times, as to require a plurality of transient current-increases to occur before the timing-device is completely changed from its second operational condition to its first operational condition; means for making a lowering adjustment of said voltage-regulating means when said timing-device reaches its first operational condition; and means for making a raising adjustment of said voltage-regulating means when said timing-device reaches its second operational condition.

16. Voltage-regulating equipment for an electrical load-device subject to transient currentincreases randomly recurring at a rate and with an intensity dependent upon the voltage, comprising, in combination; a supply-circuit for said load-device; voltage-regulating means associated with said supply-circuit; a space-current arcingdevice of a type having an anode-cathode arcingspace which is normally substantially non-conducting, starting control means for initiating the conductive operation of said anode-cathode arcing-space, said space-current arcing-device being of a type in which the anode-cathode current, once started, will remain flowing, independently of the subsequent condition of said starting control means, as long as any substantial unidirectional voltage is applied to said anode-cathode arcing-space; direct-current energizing-means for the anode-cathode circuit of said space-current arcing-device; means responsive to loaddevice current-increases of a predetermined intensity for causing said starting control means to be operatively energized; timing-means responsive to the anode-cathode current of said space-current arcing-device for subsequently interrupting the current-carrying operation thereof; and means responsive to the anode-cathode current of said space-current arcing-device for producing a lowering adjustment of said voltageregulating means.

MYRON J. BROWN.

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