US1988349A

US1988349A - Alternating current actuated controller

Info

Publication number: US1988349A
Application number: US646284A
Authority: US
Inventors: James E Beggs
Original assignee: General Electric Co
Current assignee: General Electric Co
Priority date: 1932-12-08
Filing date: 1932-12-08
Publication date: 1935-01-15
Anticipated expiration: 1952-01-15

Description

Jan. 15, 1935. J E BEGGS ALTERNATING CURRENT AGTUATED CONTROLLER Filed Dec. 8, 1952 Inventor: James BBgggs,

big Aw His Attorney.

Patented Jan. 15, 1935 PATENT OFFICE ALTERNATING CURRENT ACTUATED CONTROLLER James E. Beggs, Schenectady, N. Y., assignor to General Electric Company, a corporation of New York Application December a, 1932, Serial No. 646,284

6 Claims.

My invention relates to circuit controlling apparatus actuated by alternating current and particularly to such apparatus whose operation is light responsive. In certain prior forms of apv ,paratus of this character in which the control "element, such as a photo-electric device, has been connected to the rest of the apparatus by relatively long leads, diiliculties in obtaining satisfactory operation have been encountered in some .cases due to the capacity effects of the long leads. One object of my invention is the provision of improved circuit controlling apparatus which will not be subject to the difliculties mentioned above. Another object is the provision of such apparatus whose operation will be independent of variations of the applied voltage.

A further object is the provision of such apparatus including a vapor electric or are discharge device which will not be subject to chattering.

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

Referring to the drawing, Fig. 1 is a circuit diagram representing one embodiment of my invention, and Fig. 2 represents a modification thereof.

In Fig. 1 of the drawing a source of supply of alternating current, which for example may be a 60-cycle, 110-volt source, is shown at 1 and 2 across which is connected the primary of the transformer 3. The secondary of this transformer is shown as comprising the windings 4, 5,

6, and 7, windings 4 and 7 being cathode heating windings. Winding 5 is connected to supply energy to the grid controlled electron discharge amplifier 8, such for example as a Pliotron tube.

The cathode of amplifier 8 is heated by a connection to winding 4 and in series with the anode cathode circuit thereof are the resistors 9 and 10 whose value may for example be 2,000 ohms and 10,000 ohms respectively. Connected across the resistor 10 is a capacitor 11 whose value for example may be 1 mf. and also the photo-electric device 12, such as a photo-electric tube, in series with the resistor 13 whose resistance for example may be 10 megohms. The grid connection of amplifier 8 is made at a point between the photo-electric device 12 and the resistor 13.

With the above-described arrangement it will be seen that since resistors 9 and 10 are arranged in series with the anode cathode circuit of the amplifier 8, the photo-electric device will be supplied only with direct or rectified current.

This is of particular advantage in cases where the photo-electric device must be arranged at some distance from the rest of the apparatus and hence would be connected therewith through relatively long leads. Since direct or rectified 5 current only is supplied to the photo-electric device I am able to avoid the troublesome capacity efiects due to the distributed capacity of the long connecting leads. In order to indicate that the leads connecting the photo-electric device 10 have distributed capacity, I have represented a. capacitor by dotted lines connected between the leads.

The amplifier 8 is shown as arranged to control the operation of the grid controlled vapor electric or are discharge device 16. The anodecathode circuit of device 16 is energized from winding 6 and in series therewith is the relay 17 which is to be controlled by the light falling upon the photo-electric device 12. The cathode 20 of device 16 is connected to be heated from the winding 7 and is also connected by the lead 18 with the point 19 in the cathode circuit of amplifier 8. The grid of device 16 connects with the arm 21 of the potentiometer 22 whose resistance for example may be 20,000 ohms. In this connection is the protective resistance 23 which may be of the order of 1 megohm.

Assuming the photo device 12 to be brightly illuminated, the direct current supplied thereto through the amplifier 8 will hold the grid of the amplifier sufficiently positive with respect to its cathode that the device will pass a maximum current. Since the potential of the cathode of device 16 is that of the point 19, the grid of 35 device 16 will at this time be sufiiciently negative to prevent the passage of current through device 16. Hence relay 1'7 will not be operated.

As the light reaching device 12 decreases the amplifier 8 passes less current and consequently 40 the negative bias of the grid of device 16 becomes less until finally device 16 is tripped and begins passing current. One of the advantages of applying a negative grid bias to the device 16 from the amplifier 8 as described above is that it 4 eliminates any chattering or intermittent operation of device 16 when the light reaching the device 12 slowly diminishes.

The above described arrangement I have found gives excellent regulation since it automatically compensates for variations in voltage of the supply circuit. Thus with an increase in applied voltage the resulting resistance drop through resistors 9 and 10 causes an increase in the negative grid bias of the amplifier 8. Con- 55 versely a reduction in applied voltage results in a decrease in the negative grid bias of the amplifier 8. By suitable proportioning of the

resistors

9, 10, and 13 this circuit may even be caused to over-compensate Within limited ranges for variations in applied voltage.

The modified form of my invention as represented by Fig. 2 is similar in all respects to that represented by Fig. 1 With the exception that the relative positions of the photo device and the resistor 13 are interchanged. As arranged in Fig. 2 the device 16 will turn on or begin to pass current in response to an increase in light rather than a decrease in light as Fig. 1.

This modified form also is more stable than that shown in Fig. 1 although it is somewhat less sensitive.

I have chosen the particular'embodiment described above as illustrative of my invention and itwillbe apparent that various other modifications may be made without departing from the spirit and scope of my invention which modifications I aim to cover by the appended claims.

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

1. In combination, a photo-electric device, a rectifying electron discharge device having a control element connected with said device, a source of supply of alternating current connected to energize said discharge device and means for energizing said photoelectric device with the current rectified by said discharge device.

2. In combination, a photo-electric device, an electron discharge device having anode and cathode elements and a grid connected with said photo-electric device, a source of alternating current supply connected to energize said discharge device and means for energizing said photoelectric device with the current rectified by said discharge device.

3. In combination, a source of supply of a1- ternating current, a grid controlled rectifying electron discharge device and means for producing a resistance drop all connected together in a series circuit, a photoelectric device connected to be energized by the rectified'voltage across a portion of said means and a connection between said grid and said photoelectric device.

4.. In combination, a source of supply of alternating current, an electron discharge device connected in circuit therewith having anode, cathode and grid elements, resistance means in said circuit arranged between the cathode and the source including a photo-electric device and a connection between said grid and said resistance means whereby the light received by said devicevaries the charge on said grid.

5. In combination, a source of supplyof alternating current, an electron discharge devicehav ing anode, cathode and gridelements and resistance means all connectedtogether in a series circuit, said means being arrangedbetween the cathode and the source and including a photoelectric tube and a connection between said grid i and an intermediate point of said means.

6. In combination a rectifying-electron dis charge device having a control grid, means constructed and arranged to supply an alternating current to said device, a resistor connected in 1 series with said device and said means, a photo-. electric device connected across saidf 're'sistor whereby it is energized by rectified current and a connection between said grid and said photoelectric device. I JAMES E. BEGGS.