US2171347A

US2171347A - Time delay relay

Info

Publication number: US2171347A
Application number: US155518A
Authority: US
Inventors: Elbert D Schneider
Original assignee: General Electric Co
Current assignee: General Electric Co
Priority date: 1937-07-24
Filing date: 1937-07-24
Publication date: 1939-08-29
Anticipated expiration: 1956-08-29
Also published as: GB496641A

Description

Aug. 29, 1939. E. D. SCHNEIDER. 2,171,347

TIIE DELAY RELAY Filed July 24, 1937 Inventor: Elbert. D. Sohne' er;

is Att orney Patented Aug. 29, 1939 PATENT OFFICE gnaw 'rma-nnmr max -Elbert n. Schneider, Scotia, N. #2., mm to General Electric Company, a corporation oi.

New York Application at 24, 1931, Serial No. 155,518

' .tomms. (01250-27) My invention relates to time delay relays o! the type wherein the delay is determined byin with the accompanying drawing. and its scopewill be pointed out in the appended claims.

In the single figure oi the drawing which is a circuit diagram illustrating an embodiment of my invention, 1, 2 representthe leads of a source is of alternating current supplxwhich, for example, may be a 60 cycle, lighting circuit at either 110 volts or 220 volts. Connected across the source is the voltage divider 3 which is shown as comprising thEresistor 4 whose resistance may, for go example, be 12,500 ohms and the potentiometer 5 having the adjustable contact 6 and having a resistance, for example, of 10,000 ohms. The electron discharge device I having the anode 8, the control grid 9 and the cathode I is arranged 23 to be energized from the source I, Z. The oath ode l0 may be connected directly with the lead 2 through the single pole single throw switch ii. The anode connects through the winding of the relay [2 either directly or indirectly with the 3 other lead I oi the source, provision being shown for supplying to the anode-cathode circuit either the voltage of the source or a higher voltage. This is accomplished by the use of the autotransiormer H and the two pole switch IS, the contacts l6 and i8 of which connect respectively with the upper end of the transformer II and with an intermediate or midpoint thereof. Thus, it the supply voltage is 220 volts, the switch will be put on contact 16, but if the supply volt- 40 age is 110 volts, the switch will be put on contact It, the voltage applied to the anode-cathode circuit in either case being 220 volts. r

The grid 9 connects with the movable contact 8 of the potentiometer through the capacitor 20, 45 which capacitor is shunted by the resistor 21,

forming a leakage path through which the capacitor may lose its charge at a predetermined rate. The capacitor 20 may have a value, for example, of 2 mi. and the resistor 2| may havea 50 value, for example, 0! l0 megohms. The cathode III in addition to its connection with the lead 2 through the switch II has a permanent connection with the lead I through the resistor 22,

whose resistor may, for example, be 0.1 megohm.

5 Assuming the switch I! to be on either contact it or it and the switch it to be in its open circuit position as illustrated, in which case no current flows in the anode-cathode circuit 01. the discharge device and the relay i2 is deenergiaed, there will be a grid current flow during those hali- 5 cycles which. for convenience, will be termed the negative halhcyclee at which the lead i is negative with respect to the lead 2. This grid current, namely the electron now which takes place during the negative halt cycles from the lead' I 10 through the resistor 22,1;0 the cathode, to the grid and to the adjacent plate of the capacitor, is that due to the potential dlfi'erence between the potentiometer contact 8 and the lead i and charges the capacitor 20 in such a manner that the terminal thereof which connects with the grid is negative, it being noted that the only connection oi the cathode with the source at this time is that through the resistor 22 to the lead i. Thus, while the switch II is open, the negative half-cycles of the supply voltage keep the capacitor 20 in a charged condition.

When the switch ii is closed, the anode-cathode circuit of the device 1 is closed, whereby the device may function to pass'current during the 25 positive hali cycles to operate the relay I! under the control of the grid 9. Closing of the switch II also serves to eifectively transfer the connection oi the cathode Hi from the lead I to the lead 2, it being noted that the connection of the cathode with the lead 2 is of negligible resisance. The charge formerly given to the capacitor 20 maintains the grid 9 sufliciently negative to prevent current flow through the device 1 until the charges on the two plates of the capacitor have had time to equalize through theresistor 2| or, at least to become reduced to such a value that the device 1 will pass current suiiicient to cause an operation 01' the relay 12. This relay may be of any desired type and itsexternal cir- 4g cult may be used to control various other devices, as desired. After the operation of relay 12, the switch ll may be opened when the relay I! will move to open circuit position and the capacitor 20 will again become charged by the grid current 01' the device 1 during the negative halt-cycles.

It will be noted that the operation oi the apparatus which I have described above and illustrated on the drawing is adapted to be controlled by the switch II which is of very simple form, 5 namely, a single pole single throw switch, and that after the closing 01 this switch the relay it will be operated only after the lapse of a predetermined time interval. The duration'ot this interval depends upon various factors such as the u value of thecapacitor, the value of the resistor a. supply voltage of either 110 volts or 220 volts.

I have chosen the particular embodiment described above as illustrative of my invention, and

it will be apparent that various 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. A time delay relay comprising a voltagedivider arranged to be connected across a source of alternating voltage, a grid controlled electron discharge device having its anode and cathode connected to be supplied vfrom said source, a switch in said cathode connection a capacitor connected between said grid and an intermediate point of said divider anda resistor connected between said cathode said said divider at a point thereof on the opposite side of said capacitor connection from said first mentioned cathode connection.

2. A'time delay relay comprising a voltage divider arranged to be connected across a source of alternating voltage, a grid-controlled electron discharge device having its anode and cathode connected to be supplied from said source, a switch in said cathode connection, a resistor connecting said cathode with a point on said divider and a resistance-shunted capacitor connecting said grid with said divider at a punt thereof between said first mentioned point and said cathode connection.

3. A time delay relay comprising a source of alternating voltage, a grid-controlled electron discharge device having its anode and cathode connected to be supplied from said source, a switch in said cathode connection, means connected with said cathode and grid and operable when said switch is open for producing a grid current during the negative half-cycles of the supplied voltage and a capacitor in series with said grid arranged to be charged by said grid current;

CERTIFICATE OF v CORRECTION.

Patent No 2,171 ,5l 7

4. A time delay relay comprising a voltage divider arranged to be connected across a source of alternating voltage, an electron discharge device having an anode, a cathode, and a grid, a. capacitor connecting said grid with said divider at an intermediate point thereof, a. switch connecting said cathode with said divider at a point thereof at one side of said intermediate point, a. resistor connecting said cathode with said divider at a point thereof at the other side of said intermediate point, and means connecting said anode with said divider at a point thereof also at said other side of said intermediate point.

5. A time delay relay comprising a grid-controlled electron discharge device arranged to be energized from a source of alternating current. an anode-cathode circuit for said deviceincluding said source of alternating current, a capacitor connected with said grid and arranged to be charged by the grid current of said device and a single pole single throw switch in said anodecathode circuit of said device for simultaneously closing said circuit and reducing the voltage applied to said capacitor.

6. A time delay relay comprising a source of alternating current supply, a voltage divider connected across said source, an electron discharge device having an anode, a cathode and a control grid, a contact relay connected between said an-- ode and one end of said divider, a resistor connecting said cathode with saiddivider at said end thereof, a switch connecting said cathode with the other end of said divider, and a capacitor having a high resistance in shunt therewith connected between said grid and an intermediate point of saiddivider.

7. A time'delay relay comprising a voltage divider arranged to be connected across a source of alternating current supply, a grid controlled elec-' tron discharge device having its anode and cathode connected with spaced points of said divider, a switch in said cathode connection, a capacitorconnected between said grid and point of said August 29, 1959.,

ELBERT D.-"-SCHNEIDER.

It is hereby certified that error appears in the printed specification of the above numbered patent requiring correction as follows: Page 2, first column, line 25, claim 1, for "said said" read and said; line 57 claim 2, for,"pont" read point; and that the said Letters Patent. should be read with this correction therein that the.se.me may conform to the record of.-the ease in the Patent Office.

Signed and sealed this 10th da of October, A.- D. 1939..

Henry Van Arsdale, Acting Commissioner of Patents;