US2394294A - Time delay relay circuit - Google Patents

Description

Feb. 5, 1946. R. nl GIUSEPPE TIME DELAY RELAY CIRCUIT Filed Oct. 4. 1940 FIGQZ lluf f m3 @Mii m4 Patented Feb. s, 194s TIME DELAY RELAY CIRCUIT Renato DI Giuseppe, Rome, Italy; vested in the Alien Property Custodian Application October 4, 1940, Serial No. 359,791 In Italy November 11, 1939 1 claim.

` made of the condenser, but the circuit is so arranged that the relay operating the switch or contact breaker to he controlled, operates during the charging of the condenser until the charging current, supplied from a constant voltage source, falls below a certain predetermined value; the system of time-delay control so obtained being used in conjunction with means adapted to repeat periodically the operation at predetermined intervals of time, always equal to each other.

The invention comprises essentially an electric circuit in which is insertedv a switch comprising pairs of two or more contacts controlling a relay of normal type, a condenser traversed by a current of suiiicient intensity for maintaining attracted the armature of said relay during a predetermined time, said relay being connected by a key adapted to open one pair of contacts for starting the charge oi the condenser, and adapted to close the other pair of contacts which re-establishes the circuit in place of the key.

The interval ci' time during which the circuits maintain the relay closed constitutes the measured unit of time.

. The device according to the present invention is shown schematically in various embodiments and by Way of example in the attached drawing, in which:

Fig. l shows a circuit in which a relay is attracted immediately upon application of voltage to its winding and remains attracted for a given time after the operating switch has been opened. (Time-delay dropout relay.)

Fig.` 2 shows a circuit similar to that'shown in Fig. l, arranged so as to compensate any variations of voltage of the supply current.

Fig. 3 shows a circuit similar to that shown in Fig. 2, comprising a time-delay relay which is energized into actuated position after a determined time from its connection, said actuated condition ceasing immediately upon its disconnection. (Time-delay pickup relay.)

Fig. 4 shows a circuit similar to those illustrated in Figs. 2 and 3, but provided with a timedelay relay retarding its action both on its connection and disconnection. (Time-delay pickup and dropout relay.)

The timed circuits which I describe may be arranged to actuate any conventional electrical impulse actuatable instrument as a counting o r recording system.

Fig. 1 Shows schematically a circuit so arranged between supply mains that the relay armature provided is attracted immediately upon its connection, and continues to be attracted for a determined time after the voltage supply has been disconnected. (Time-delay dropout relay.) In such circuit, the relay winding I, is energized immediately on closing button Il, while condenser I8 is short circuited by said contact button il, and is thereupon discharged. When the circuit is opened, through the opening of contact hutton I'l, the relay winding I continues to be trav ersed by current, until the value of said charging condenser current falls below a certain determined value.

Fig. 2 shows schematically a circuit similar to that shown in Fig. 1, and connected across supply mains, but provided with means adapted to compensate any variations of voltage of the sup ply current. These means consist in forming the relay on an E shaped core, comprising two wind ings I4 and I5 on the respective outer legs, and an oscillating bar armature I6 pivoted between said core windings on the legs, one of which may be connected as the relay winding I shown in Fig. 1, and the other may be shunted across the supply voltage with an adjustable resistance con nected in series, thus acting as an opposing force.

With the arrangement just described, both the actuating force of the relay, due to the charging current of condenser I8, and the opposing force which causes the relay contact and the condenser to be disconnected, when said actuating force de-s creases, are proportional to the voltage of the cur-n rent, i. e., they vary similarly with the variations of the latter, and consequently the operation of the device depends solely on the electric charu acteristics of the circuit, and so remains practically constant even during any variations of the voltage.

In the circuit shown in Fig. 2, the rheostats I9 and 20 are used for adjusting, within certain limits, the time characteristic of the circuit.

Fig. 3 shows a circuit similar to that shown in Fig. 2, with which however the opposite eect is obtained, i. e., a retardation of the closing of the relay (time-delay pickup relay). In this circuit, winding- Il is the active one, while winding I provides the opposing force; these two windings are so designed that on pressing the key 2| from its normal spring urged position as shown, the winding Il is connected and. the normally closed short circuit across condenser I8 is opened and condenser I2 starts to charge through winding I5 energizing the latter, but the force produced by winding I4 is not sufficient for attracting immediately the movable armature IS, and consequently a time t has to pass between said connection and the actual attraction of armature I6, after which the current charge of condenser I8, drops to such a low value, that the current traversing the winding i5 falls below and is overcome by that traversing the winding I4. Also in this case the time-delay depends on the values of condenser I8 and resistances I9 and 20.

The relay shown in Fig. 3 has a quick return to unactuated position, viz.; as soon as key 2| is released, the movable pivoted armature I6 is immediately attracted again by the winding I5.

The circuit shown in Fig. 4 is a time-delay pickup and time delay dropout relay. In fact, in this circuit, on pressing the button 2l, the operation above described for the circuit of Fig. 3 is obtained, and on releasing said key 2l, the operation described for the circuit of Fig. 2 is obtained. The values of the two time-delays depend on the values of the condensers I8 and 23 and of the resistances I9, 20 and 22. Condenser I8 is connected across the xed contacts of switch 2l which make connection to the restraining winding I5, and by its charging current causes winding I5 to restrain the actuation of relay armature I 6 when button 2l is depressed. Condenser 23 is connected across the fixed contacts oi' switch 2| which make connection to the actuating winding I4, and by its charging current delays the reduction of the current through actuating winding Il to armature releasing value when button 2| is released from depressed position.

It will be understood that the controlling circuit of an electrically actuatable instrument whose operation is to be controlled with time delay characteristics, may be connected to the controlled contact of armature Ii.

What I claim is:

In control means for an electric timing circuit, electromagnetic relay means having a set of controlled contacts and further having an operating and a restraining winding magnetically opposing each other, a switch having two positions and having a rst pair and a second pair oi' controlled contacts and adapted in a given position to selectively connect together either said first pair or said second pair of contacts but not both pairs, a source of electrical energy, a iirst contact of each of said pairs being connected to a first terminal of said source, the second contact of said first pair being connected to a rst terminal of said operating winding and the second contact of said second pair being connected to a first terminal of said restraining winding, the second terminals of said windings being connected to the second terminal of said source, and a pair of electrical time delay circuits each comprising electrical energy storing means respectively connected across said'pairs of contacts respectively.

RENATO DI GIUSEPPE.

Images