USRE21533E - Apparatus for controlling electri - Google Patents

Description

Aug. 13, 1940. E. R. STOEKLE ET AL 21,533

APPARATUS FOR CONTROLLING ELECTRICAL AND OTHER OPERATING CONDITIONS OF ELECTRICAL QIRCUITS Original Filed July '20, 192-3 v Inventors v d eczased,

by CuHer Hammer, Inch, by wcsievens, Vice, President QMRW 55M y MXW Attorney Reissued Aug. 13, 1940 APPARATUS FOR CONTROLLING ELECTRI- CAL AND OTHER OPERATING CONDI- TIONS OF ELECTRICAL CIRCUITS Erwin R. Stoekle, deceased, late of Milwaukee,

Wis" by Cutler-Hammer, Inc., assignee, Millwaukee, Wis, and Arthur Simon, Milwaukee, Wis; said Stoekle and said Simon assignors, by mesne assignments, to said Cutler-Hammer, Inc., a corporation of Delaware Original No. 1,582,702, dated April 27, 1926. Se-

rial No. 652,713, July 20, 1923.

Application for reissue March 16. 1939, Serial No. 262,322

12 Claims.

This invention relates to method of and apparatus for controlling electrical and other op-. erating conditions of electric circuits.

More particularly the invention relates to light responsive control of such conditions of a circuit or circuits.

The present invention is disclosed in our copending application Serial No. 175,992, filed June 21, 1917, of which the present application is in the nature of a continuation, an adaptation of the present invention to the fluid metering art being claimed in saidcopending application. Also certain features of the present invention are disclosed but not claimed in prior patent of E. R. Stoekle #l,361,197 of Dec. 7, 1920, filed Oct. 5, ll 1917.

The present application contemplates adaptation of the invention to control of electrical and other operating conditions of electric circuits generally.

8) Thus an object of the present invention is that of providing for light responsive control oi'electrical and other operating conditions, other than or in addition to electrical continuity, of one or more electric circuits.

35 Another object is that of providing for exceedingly sensitive, accurate and reliable control in'- cluding light responsive control of such conditions of an electric circuit or circuits.

Another object is that vof providing advantageous methods of eflecting such control.

Another object is that of providing improved apparatus for enactment of the aforementioned methods.

Other objects and advantages will hereinafter In the accompanying drawing, wherein are illustrated certain of the embodiments which the invention may assume in practice.

Figure 1 is a diagrammatic and schematic view illustrating generically applicability of the invention to the control of electric circuits, as exemplifled in the motor field circuit shown: while Fig. 2 is a similar'view, corresponding to the single view or figure of our copending application aforementioned, and further illustrating the general applicability 0! the invention, the same being in this case applied in the fluid metering art.

Referring to the drawing and particularly to a Fig. 1 thereof, the same illustrates an electric (Cl- Inf-239) circuit, viz, that including coil 1, to be regulated as to its electrical and other operating conditions in accordance with the methods hereinafter set forth. In the embodiment illustrated said circuit comprises the shunt field circuit of a motor having an armature A to be supplied from D. C. lines LL across which said field circuit is also connected, said lines to be in turn supplied from a suitable or convenient source such as lines LL, transformer T and rectiflers RR.

Obviously by the foregoing arrangement the speed of motor armature A is controllable through energization control of the circuit of its field coil I, as by rheostat liL whereas, by the means now to be described, control of the setting of said rheostat is effected automatically in accordance with and to compensate for variations in speed of the motor and also with exceeding accuracy and sensitivity.

To such end a reversible operating motor II is provided for rheostat In, said motor having a shunt field j to be connected across lines UL and having its armature circuit also connected across said lines by means of a Wheatstone bridge connection as illustrated.

Two legs of said bridge comprise fixed resistances r and 1', while the other two legs thereof comprise variable resistances r and r". the latter being illustrated as of the carbon pile type. Thus the variable resistances r and 1'' provide by relative adjustments thereof, for selectively rendering the motor inert, starting the same in either direction and varying the speed thereof, said resistances being so adjustable by an element i2 controlled by electro-magnets l3 and It. The electro-magnets i3 and it are arranged to act diflerentlally upon the member i2 and controllable through the medium of selenium cells l and Hi to vary the relative adjustment of said resistances.

More specifically, the windings oi the electromagnets l3 and II are connected in parallel across the D. C. circuit with the selenium cell IS in the branch of the electro-magnet I3 and the selenium cell It in the branch of the electromagnet ll. 7 Thus as will be understood, the selenium cells may be influenced to render either electro-magnet predominant for starting the motor i i in a corresponding direction and moreover predominant to varying degrees for graduation beams of light of varying intensity and it is in.

ofthe speedofth'emotor- Also.aswillbe imderstood, the selenium cells may be influenced to produce such results by subjecting the same to such a manner that said electro-magnets II and I4 are subjected to'energization control jointly and diflerentially in accordance with variations in speed of armature A, as by the means now to be described.

To such end a flyball governor l", or its equivalent is arranged to be actuated by said armature and uponvariation in speed of the latter to eilect corresponding and proportional adjustment of levers l which in turn correspondingly varies the apportionment of resistance between the legs rr' of another Wheatstone bridge 9 also connected across supply lines W. the other two legs of said bridge comprising flxed resistors 1' 7. Said bridge 9 is further provided. with a galvanomcter G of the mirror type. A i

The galvanometer is subjected to a beam of light from a linear source I and reflects such light through a shade screen I! and a cylindrical lens is onto the selenium cells. The screen I! is provided with an opaque band I! which divides the beam of light reflected by the galvanometer intoseparate and distinct beams for the two cells. Also, the screen sections on opposite sides of the band are shaded in a reverse relation, whereby the most opaque portion of the upper section is aligned with the most transparent portion of the lower section, with the result that as the galvanometer mirror shifts its position to decrease the intensity of light reflected on one selenium cell, it will at the sametime correspondingly increase the intensity of light reflected on the other cell. The arrangement thus provides for influencing the selenium cells throughout a wide range and to a degree proportional to the deflection of the galvanometer.

Hence, assuming an adjustment of the apparatus such that the galvanometer equalizes the beams of light reflected upon the selenium cells I is under given or desired speed conditions of armature A, the setting of the various control instrumentalities, including rheostat it, will be maintained so long as such speed remains constant. However, upon occurrence of a change in speed of said armature the bridge 9 is adapted to become unbalanced, thereby causing deflection of the galvanometer andof the beam of light projected upon selenium cells II and I in a corresponding sense and to a proportional degree. As aresult of such action motor ll becomes correspondingly energized for eflecting such adjustment of rheostat II, and consequent regulation of the energization of coil I as to restore thev desired speed conditions of armature A. Moreover following each such .adjustment the balance of bridge 9 is restored whereby the galvanometer will resume its initial position for maintaining the adjustment pending subsequent change in speed of said armature A.

Obviously if said armature be subjected to conditions of constant load and energiaation. the fleld I being separately energized, the device is adapted to maintain a constant value of the energization of said fleld circuit irrespective of variations in electrical conditions of its source.

In Fig. 2, which is identical with the illustration of our copending application aforementioned is illustrated a 7 different adaptation of the aforedescribed control, to the fluid mea1,sss

'In this instance the coil 1, corresponding to the fleld coil 1*, aforedescribed comprises the 1.). C. or control winding of a magnetic amplifier I. having an A. C. winding 2| which is arranged to be in circuit with an electric heater 22. a wattmeter W being also arranged in circuit to measure the electrical inputto said heater. Said heater is utilized in a conventional type of fluid meter for imparting continuously to the stream of fluid flowing in a conduit 23 such values of heat as to maintain a constant temperature rise of the stream of fluid passing said heater. irrespective of variations in rate of flow of said stream of fluid. Under such conditions, the variations in rate of energy input to the heater constitute a measure of the variations in rate of flowof the fluid whereby the wattmeter W may be either of the indicating or the integrating type. The control means aforedescribed in connection with Fig. l is herein utilized for controlling and varying the electrical input to the heater accurately in accordance with and to compensate for variations in temperature rise of the fluid, which are incident and proportional to variations in its rate of flow.

To such end resistance thermometer units 24 and 25 each comprising essentially a resistor adapted to change in ohmic value proportionally to changes in temperature to which the same is subjected, are arranged in the stream of fluid for subjection to the temperature thereof before and after passing the heater 22. Said resistance thermometer units are respectively, connected in series with and constitute in effect portions of the individual resistance legs 1' and r of Wheatstone bridge 9.

It thus follows that a change in temperature ,rise of the fluid will cause unbalance of said bridge, whereby the various control instrumentalities are actuated, as in the construction of Fig. 1 aforedescribed, for effecting proportional variation in energization of coil 1, which changes are transmitted in amplified form to the circuit ofheater 2! and are indicated by wattmeter W.

It will be readily understood that employment of magnetic amplifier 20 enables control of relatively high values 'of A. 0. electrical energy in the heater circuit through control of relatively feeble values of D. C.,energy whereby the rheostat I I and its associated instrumentalities may be of correspondingly light and even delicate construc-' ,of the circuit including the heater 22, whereas the character or such control is in no wise dependent upon the character of the power consuming. or translating devices included in such circuits. On the other hand such field coil and heater or the like areto be regarded as merely typical of certain of the classes of devices to which the present control system is applicable.

What we claim as new and desire to secure by letters Patent is:

l. A device for controlling an electrical condition of a circuit, comprising means sensitive to an electrical condition or said-circuit. means condirection and the actual direction of the beam.

2. In a control system of the character described, in combination, electro-responslve circuit controlling means, means sensitive to variations in light for governing the operation thereof and means responsive to varying electrical conditions for subjecting said sensitive means to variations in light.

3. In a control system of the character described, the combination with electro-responsive means including an electric motor and control means therefor, of means sensitive to variations in light for influencing said control means and means coordinated with said electro-responsive means and responsive to varying electrical conditions for subjecting said sensitive means to variations in light.

4. In a control system of the character described, in combination, a Wheatstone bridge, electro-responsive means, and means for subjecting said electro-responsive means to the influence of said Wheatstone bridge upon unbalancing thereof, said second mentioned means including a selenium cell associated with said electro-re sponsive means and a galvanometer device associated with said Wheatstone bridge to subject said selenium cell to variations in light.

5. In a control system of the character described, in combination, a Wheatstone bridge to be subjected to conditions tending to unbalance the same, electro-responsive means to be influenced by said bridge upon unbalancing thereof, said means being co-ordinated with said bridge for operation to restore the latter to balanced condition, and means for subjecting said electroresponsive means to influence by said bridge, including a selenium cell associated with said electro-responsive means and a galvanometer device associated with said bridge to subject said selenium cell to variations in light.

6. In a control system 01 the character described, in combination, a Wheatstone bridge to be subjected to conditions tending to unbalance the same, means including electro-responsive elements differentially related to each other to be influenced by said bridge upon unbalancing thereof, said means being co-ordinated with said bridge for operation to restore the latter to balanced condition, and means for subjecting said first mentioned means to influence of said bridge including a plurality of selenium cells associated respectively with said electro-responsive elements and a galvanometer device associated with said bridge to subject said selenium cells to variations in light.

'1. A control mechanism comprising, in combination, a circuit operatively including a resistor and a contactor engaged therewith and movable therealong, a source of light, a galvanometer electrically connected to a fixed portion of said circuit and operatively connected to said movable contactor, a mirror carried by an oscillatable part of said galvanometer and arranged to reflect a beam of light from said source, photosensitive electrical means in the path of the beam of light reflected from said mirrorand having a characteristic variable in accordance with the deflection of the beam of light with respect to a balanced position of the galvanometer, relay means responsive to the operation of said photo- I sensitive electrical means, and means including areversible electric motor controlled by said relay means to operate said movable contactor toward a galvanometer-balancing position.

8. A control mechanism comprising, in combination, a circuit including a'resistor and a con-' tactor engaged therewith and movable therealong, a source of light, a galvanometer electrically connected to a fixed portion of said circuit and to said movable contactor, a mirror carried by an oscillatable part of said galvanometer and arranged to reflect a beam of light from said source, photo-sensitive electrical means in the path of the beam of light reflected from said mirror and having a characteristic variable in accordance with the deflection of the beam of light with respect to a balanced position of the galvanometer, relay means responsive to the opv, eration of said photo-sensitive electrical means,

"and means including a reversible electric motor controlled by said relay means to operate said movable contactor toward a galvanometer-balancing position.

9. -In combination, a galvanometer having amirror for deflecting a beam of light reflected therefrom. relative to a null positionof the beam, means for operating said galvanometer to effect such deflection of the beam, photo-electric means in the path of the beam, a reversible electric motor governed by said photo-electric means, and means actuable by said motor to restore the beam to the null position upon adeflection therefrom.

10. In combination, a galvanometer having a mirror for deflecting a beam of light reflected therefrom relative to a null position of the beam, means for operating said galvanometer to eflect such deflection of the beam, photo-electric means in thepath or the beam,- relay means operable by said photo-electric means, a reversible electric motor governed by said relay means, and means actuable by said motor to restore the beam to the eration of said movable element, means positioned by the galvanometer to affect the light reaching the photo-electric means in accordance with the position of the galvanometer, means operativelyconnecting the photo-electric means with saidmovable element and controlled by the photo-electric means to operate the movable element in accordance with the position of the galvanometer, whereby the value of said physical condition is maintained substantially constant.

12. In combination, means havinglan electrical characteristic adapted to be varied in accordance with variations in a physical condition such as temperature, a galvanometer connected to said means and responsive to variations in said characteristic, comparison balancing means connected to the galvanometer, associated means having an automatically variable value for e1- iecting balancing of said first named means against said comparison balancing means, said associated means including a movable element.

4- Y sues I a llght photo-electric means for governing the operation of said movable element, means positioned by the galvanometer toafl'ect the light reaching the photo-electric means in accordance with the position of the galvanometer, means operatively connecting the photo-electric means with said movable element and controlled by the v photo-electric means to operate the movable element in accordance with the position of the galvanbmeter, said associated means also including means governed by said' movable element for controlling said physical condition.

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