US1834786A - Electrical control means - Google Patents

Description

F. KAcsER ELECTRICAL CONTROL MEANS Filed Jan. 18, 1930 Figi Im/en tc r`l Fel ix Kassen,

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Patented Dec. l, 1931 UNITED STATES FELIX KACSER, or BERLIN, GERMANY, AssIGNoR'ro GENERAL ELECTRIC COMPANY,

A CORPORATION OF NEW A'YORK ELECTRICAL CONTROL MEANS Application led January 18, 1930, Serial No. 421,824, and in Germany Hatch 20, 1929.

My invention relates to electrical control means, and particularly to electrical regulators of the vibratory cont-act type in which the contacts are operated by electrostatic forces.V

The ordinary vibratory contact type of electrical regulator, as exemplied by the Tirrill type regulator, usually depends for its action upon elcctromagnetically produced forces for moving the contacts. These forces are generallypro duced by cooperating electromagnet coils and plungers, the latter often being counterbalanced by weights or springs. Such operating means, While capable of giving very satisfactory results, are nevertheless composed of swinging elements having an appreciable inertia and hence are subject to a'hitherto unavoidable time lag in operation. Furthermore, these swinging elements have a natural period of vibration which, unless damped, may cause operating difliculties. I propose to utilize the phenomenon of the attractive force between bodies carrying unlike electrostatic charges to produce a vibratory contact action.

. It is an object of my invention t-o provide a new and improved electrical control means. It is a further object of my invention to Iprovide a new and improved electrical regulator of the vibratory contact type, whose contact operating means are extremely simple and strong. I

It is an additional object of my invention to provide an electrical regulator of the vibratory contact type whose contact operating means are practically inertia-free and which have no natural period of vibration.

My invention will be better understood from the following description taken in connection with the accompanying drawings and its scope will be pointed out in the appended claims.

In the drawings, Fig. 1 is a diagrammatic representation of my invention as embodied in a regulator for a direct current generator, while Fig. 2 is similar to Fig. l but includes additional means for superimposing a substantially constant frequency vibratory action of the contacts upon the natural regulating action thereof.

i Referring now to Fig. 1, reference character 1 represents a direct current generator whose terminals are connected across a supply circuit 2. This generatorcomprises an armature 3 and a shunt eld winding 4 which is connected in series with a resistance 5 across the terminals of the machine. Connected so as to be capable of short-circuiting resistance 5 are a pair of contacts 6 and 7 the former being adjustably' mounted relative to the latter as shown. Also connected across the terminals of machine 1 are a pair of conducting plates 8 and 9 which are separated by a dielectric 10. Contact 7 is insulatingly mounted upon plate 9 by means` 'of insulation 11. Dielectric-10 is composed of some strong elastic material having no natural vibratory period, such as soft rubber. Contacts 6 and 7 plates 8 and 9 and insulation l form what will hereinafter be referred to as an electrostatic relay. The conducting plates 8 and 9 may either be pressed on to the surface of the dielectric 10 in such a manner as to exclude any air or they may be galvanically .deposited upon dielectric 10, in which case, of course, there will be no air trapped between the two.

The operation of this embodiment is as follows: Assume that generator 1 is being operated at its normal speed and that contact 6 is adjusted so that it is in engagement y with contact 7 Under these conditions resistance will be .short-circuited and'there Will be a maximum current flowing through field 4, thereby causing a high terminal voltage to be generated by machine 1. However, if the terminal voltage 'exceeds a predetermined amount the electrostatic attraction between plates 8 and 9, which are of course oppositely charged, will compress the elastic diretric enough to 'separate contacts 6 an 1 Y When this Occurs resistance 5 is inserted in the shunt circuit with winding 4, thereby decreasing the field current and hence the generated field ofthe machine. However, as soon as the generated voltage falls below a predetermined amount the lessened attractive force between plates 8 and 9 will allow the elastic dielectric 10 to expand and again cause engagement between contacts 6 and 7. As plates 8 and 9 are made extremely thin, and consequently very light, it will be seen that the action of the regulator will be exceedingly rapid, there being no parts having sufiicient inertia tolintroduce appre.- ciable time lag in the operation.

Should a load change on supply circuitv 2 occur the tendency will be to either lower or raise the terminal voltage of generator 1, depending upon whether the change in load was an increase or a decrease. I-Iowever, as the action of contacts 6 and 7 is solely a function of the terminal voltage of the machine the effect of such change in load will be to merely vary the ratio of the time open to the time closed of these contacts. It will thus be seen that the regulator tends to hold constant voltage regardless of load changes onsupply circuit 2.

By adjusting the position of contact'6, the voltage at which contacts 6 and 7 separate or become engaged may be readily varied. Since, however, most regulating actions are improved when they are superimposed on a periodical action, an auxiliary alternating potential may be applied across the plates 8 and 9. If, however, no external source of such an alternating potential is available, a system such as that shown in Fig. 2 may be employed.

Referring now to Fig. 2, 12 represents a I direct current generator, whose terminals ture of this machine.

are connected across supply circuit 13. This generator has a direct current commutator 14 and a shunt field 15 connected in series with a resistance 16. Arranged to shortcircuit resistance 16 are contacts 17 and 18, contact 17 being adjustably mounted as shown. Connected across the terminals of machine 1 through choke coils 19 and 20 are a pair of metallic conducting plates 21 and 22 separated by al dielectric 23. Machine 12 is also provided with slip rings 24 for drawing alternating current from the arma- '.Ihese slip rings are also connected across plates 21 and 23 in such a way that the choke coils 18 and 19 prevent the alternating current from reaching the supply circuit 13. Plates 21, 22 and dielectric 23 are constructed of the same-materials and in the same manner as are plates 8 and 9 and dielectric 10 of Fig. 1.

The opera-tion of this embodiment is as follows: Assume that machine 12 is being driven at its normal speed and that contacts 17 and 18 are in engagement. Under these circumstances the main regulatory action will be similar to that when the terminal voltage of the machine exceeds that for which the contacts are set to open, resistance 16 will be inserted in the circuit of field 15, thereby reducing the field current and the terminal voltage of the machine and consequently causing a reengagement of the contacts.' Due to the adjustability of Contact 17, the predetermined voltage at which contacts 17 and 18 open and close may be varied over a considerable range. Due to the alternating voltage across slip rings 24 which is communicated to plates 21 and 22, the latter will have a relatively rapid vibratory motion with respect to each other, that is to say, plate 22 is fixed4 and contact 18, which is supported by plate'21, will have a small but relatively rapid vibratory action. The result of this rapid vibratory action of contact 18 will be to hold an average current in the field winding 15 which corresponds to the voltage which the regulator is set to maintain. Therefore, as this action is comparatively rapid there will be but very slight rapid and periodic variations in the generated voltage of the machine 12, whereas the regulator of Fig. 1 may produce a hunting action, causing fairly wide periodic voltage variation.

While I have shown and described particular embodiments ofv my invention it will be obvious to those skilled in the art that changes and modifications may be made without dcparting from my invention and I, therefore,

aim 1n the appended claims to cover all such changes and modifications as fall within the true spirit and scope of my invention.

What I claim as new and desire to secure by Letters Patent of the United States is:

1. In combination, a pair of contacts and means for moving said contacts relatively to each other, said means including a pair of relatively movable conductors separated by an elastic dielectric.

2. In combination, a pair of contacts and means for moving said contacts relatively to each other, said means including a pair of conductors in intimate contact with opposite sides of an intermediate dielectric of soft rubber.

3. In an electrical regulator of the vibratory contact type, a pair of contacts, means for moving said contacts relatively to each other, said means including a pair of relatively movable conducting plates separated by an elastic dielectric.

4. In an electrical regulator, a pair of controll contacts, means for moving said contacts relatively to each other, said means including apair of thin` metallic plates separated by a resilient dielectric substance.

5. In an electrical regulator, a pair of control contacts, means for moving said contacts relatively to leach other, said means including a pair of conducting plates separated by soft rubber.

6. In combination, an electric circuit, a regulator of an electrical condition of said circuit, said regulator including a pair of cluding a pair of relatively movable conducting plates separated by an elastic dielectric.

7. In combination,- an electric circuit, a regulator of an electrical condition of said circuit, said regulator including a pair of control contacts, and means for moving said contacts relatively to each other in response to variations in said condition, said means including a pair of metal plates fastened to opposite sides of a sheet of soft rubber.

8. In an electrical regulator of the vibratory contact type, a pair of main control contacts, means for causing a regulator movement of said contacts, said means including a pair of relatively movable conducting plates and an elastic dielectric therebetween, and means for causing a rapid vibratory relative motion of said conducting plates.

9. In combination, an electric circuit,

means connected to said circuit for varying an electrical condition thereof, regulatory means associated with said circuit and said condition varying means for maintaining said condition constant, said regulatory means including a pair of main control contacts and means for moving said contacts relatively to each other in response t0 variations in said electrical condition, said means including a pair of relatively movable conducting plates and an elastic dielectric therebetween,

and a source of periodic voltage variations connected between said conducting plates.

lO. In combination, an electric circuit, a direct current generator connected thereto, a voltage regulator for maintaining constant voltage on said circuit associated with said circuit and said generator, said regulator including a pair of control contacts, means for permitting relative movement of said contacts, said means including a pair of relatively movable conducting plates and an elastic dielectric therebetween, conductors connecting each conducting plate to a different side of said circuit, choke coils connected in said conductors and a source of periodic voltage variations connected across said conductors between said choke coils and said conducting plates.

In Witness whereof, I have hereunto set my hand this 2nd day of January, 1930.

FELIX KACSER.

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