US2309558A - Voltage regulator for electric generators - Google Patents

Description

Jan. 26, 1943 w. G. I WEATHERLY 2,309,558

VOLTAGE REGULATOR FOR ELECTRIC GENERATORS Filed Sept. '16, 1941 WILLJAM 6. WEATHERLY 8 @NM W! Patented Jan. 26, 1943 OFFICE VOLTAGE REGULATOR FOR ELECTRIC GENERATORS William G. Weatherly, Wenatchee, Wash.

Application September 16, 1941, Serial No. 410,990

1 Claim.

This invention relates to controls for automobile generators of the type operating to adjust the generator output to the load requirements.

The principal object of this invention is to provide a means to assure a nearly constant voltage.

A second object of this invention is the provision of such means in a. compact and inexpen sive form readily adaptable for installation as a part of automobile electrical systems.

Other objects and advantages will be apparent in the following discourse,

In the drawing:

The figure is a diagrammatic representation of the elements embodied in combination.

The essence of this invention resides in the means provided to effect the regulating operation in degrees unrelated to the value of potential increase upon which the device relies for control.

Referring now more particularly to the draw- A generator I is wound with a shunt field 2 and a control field 3 the force of which opposes the shunt field. A storage battery 4 of conventional type is connected in parallel to the generator I. Interposed in the shun-t field circuit is a resistance 5, an actuating coil 6, and the control field in series connection. A pilot coil I connected across the generator output as indicated, and a compensating coil 8 connected in series with the load, together with the actuating coil 6, are windings controlling the longitudinal movement of a core 9 in conventional solenoid arrangement A frame I0 is rigidly attached to the core 9 at one end and carries at its extremity the sliding contact H, slidable along the resistance 5. This slidable contact I I is connected to the ground as indicated. A tension spring l2, secured at opposite ends to a stationary attachment I3 and a hook ll formed upon the frame 10, urges the core 9 to a normal position within the coils 6, 1, and 8.

Heretofore, it has been common practice in devices of this type to use a potential coil, analogous to the pilot coil 1 in the present application. to actuate a variable resistance in certain degrees proportional to the voltage increase. In such types of control devices, it will be recognized that as the load requirements diminish the voltage will constantly rise owing to the necessity of the use of increasing forces to actuate the variable resistance to its fullest capacity.

In contrast to this practice. the present invention contemplates the maintenance of a predetermined nearly constant voltage. This is accomplished by providing the energy for the operation of the variable resistance from a separate source, but, in turn controlled by the behavior of the pilot coil 1 which registers a voltage rise of almost any practical value. The magnetic force developed by a minimum voltage rise, though insufficient to actuate the core and hence the variable resistance through amplitudes ef fective to prevent voltage rise, operates to energize the actuating coil 6 by diverting additional current therethrough.

To trace the operation of the device in detail:

The pilot coil 1, being connected across the generator output, will respond to the slightest voltage rise to exert a force on the core 9 of, let it be assumed, a minimum value. As soon as the shunt field circuit is completed to ground through one end of the resistance 5 and the sliding contact II, and the control field circuit is likewise completed to ground through the remaining end of the resistance 5 and sliding contact H, the slightest movement of the contact I i, in response to the action of the pilot coil 1, will result in an adjustment of the proportions of the generator current which fiow through the shunt field and control-field windings respectively.

This alteration of the intensity of the current fiowing in the circuits will thus alter the value of the current in the actuating coil 6 in a manner to augment the effects produced upon the core 9 by the pilot coil 1. Thus, in a sense, the device may be said to be regeneratively actuated. That is to say, the action of the pilot coil 1 may be amplified in any desired degree by a choice of the ampere-turn capacities of the coils 6 and I, coupled with the selection of a suitable potential gradient characteristic for the resistance 5.

Let it be assumed that an increase in voltage of one fourth of a volt is necessary to actuate the core 9 through a movement effective to register a change in the relative resistance values of that part of the resistance 5 considered, and that a variation of one fourth of a volt is within the tolerance for which the apparatus as a whole is designed. It will be apparent that regardless of the magnitude of the load, an increase in generated voltage of one-fourth volt will result in the curtailment of'the generator output to the precise requirements of the load.

The compensator coil 8, exerting force in opposition to those of the coils 6 and 1, modifies the precise position of the sliding point II at which the regulation occurs. As the compensator coil 8 is in series with the load, it will be apparcut that as the load increases, resistance will be cut out 01 the shunt winding and cut into the control-field, thus providing for the increased field strength necessary to carry the increased load.

Proper determination of the current-carrying capacities of the several coils and resistances employed will insure maximum eiiiciency and minimum of heat losses.

While I have shown a particular form of embodiment of my invention, I am aware that many minor changes therein will readily suggest themselves to others skilled in the art without departing from the spirit and scope of the invention. Having thus described my invention, what I claim as new and desire to protect by Letters Patent is:

Generator control apparatus comprising in combination with a generator having a shunt held and a control winding magnetically associated to oppose the field, a resistance and an actuator coil connected together in series and to one terminal each of said field and said control winding respectively, a pilot coil connected across the generator output magnetically associated with said actuator coil, a compensating coil connected in series with a load and the generator output magnetically associated with said actuator and pilot coils, the latter coils being wound to magnetically oppose said compensator coil, a core operable through said actuator, pilot, and compensator coils, means urging said core in op position to the magnetic etlects thereupon of said actuator and pilot coils, and selective tap means associated with said resistance controlled by said core to complete the circuit with the generator output of the said field through a portion 01. said resistance determined by the relative adjustment of said tap the remainder of which is in series through said tap with said control winding across the generator output.

WILLIAM G. WEATHERLY.

Images