SU849330A1 - Timer - Google Patents

Description

(54) TIME RELAY

I

The invention relates to automation, in particular to time delay devices.

Time relays are known that are made on the basis of self-holding double-winding relays, in which current pulses are controlled, containing a first capacitor connected through a diode between the power supply buses, a second capacitor connected through the diode between the power supply bus and the zero-input input with the executive a relay as a load, a resistive divider of the power supply voltage, a resistor connected in parallel to the capacitor, a return winding of the actuating relay connected between the midpoint d numerator power supply voltage and the input of the zero-body made at the equivalent of two-base diode 1.

A disadvantage of this device is the use of a low impedance divider to set the potential on the second capacitor, which leads to an increase in power consumption, as well as a low stability of time exposures, because the holding time

is added up from the time of discharge of the first capacitor to the level of the second and the time of supplying the supply voltage to the relay.

The supply time of the control voltage to the relay is usually not constant, that 5 leads to time-varying volatility.

The closest technical solution to the present invention is a time relay containing an amplifier on two, transistors with an RC.-chain connected to the base of one of them, and a winding of an electromagnetic relay connected to the collector circuit of the other, a starting switch connected to the negative power pole , the additional winding of the mentioned two-position relay

A self-contained IS connected between the start key and the positive pole of the power supply and the capacitor 2.

A disadvantage of this device is the dependence of the readiness time for the next cycle on the exposure time. As the time delay increases, the resistor's resistance time of the driving RC circuit increases, which also leads to an increase in

preparation time for the next cycle. Failure to comply with the time interval to prepare for the next cycle leads to instability of the time delay or failure of the relay on the additional winding, since the time specifying the capacitor and switching capacitor is not fully discharged.

The purpose of the invention is to improve accuracy with low power consumption of a time relay.

To reach the goal, a time relay containing an RC driver circuit, connected by an output to the input of a threshold amplifier with a tripping winding of an electromagnetic relay in the collector circuit of the output transistor, a start switch connected to one of the terminals with a power source, an additional winding of the mentioned relay , made on-off with self-holding, the key-driver on the transistor with the time setting circuit and the threshold zener diode in the base circuit is inserted, while the starting key is included in the emitter circuit In a key driver transistor, the collector of which is connected via an additional winding of an electromagnetic relay with a power source, the capacitor time of the driving RC circuit is connected through a limiting resistor to the collector circuit of the key driver.

The drawing shows the electrical circuit of the time relay.

The time relay contains a threshold amplifier 1 on two transistors of different types of conductivity, covered by a positive feedback, disconnecting winding 2, resistor 3, condenser 4, forming the time specifying the RC circuit, limiting resistor 5, additional winding 6, start switch 7, switch- driver on the transistor 8, the Zener diode 9, the resistor 10, the driving circuit on the capacitor 11, the resistor 12.

The time relay works as follows.

When the supply voltage is applied, the two-position relay is reset. This is achieved by the fact that at the first instant of time the transistors of the threshold amplifier 1 are in the closed state, as the capacitor 4 is charged through the winding 6 of the relay, and the resistors 5 and 3.

When the capacitor 4 reaches a voltage equal to the response voltage of the threshold amplifier I, the winding 2f of the electromagnetic relay is activated. Relay

time is set to the original connection.

In the case of a short-circuiting start switch 7, it opens due to the RC chain, consisting of a resistor 12 and a capacitor 11, a transistor 8 of a key-driver. This causes the additional winding 6 to be triggered to discharge the capacitor 4. After the transistor 8 is closed, the capacitor 4 begins to charge, which forms the time setting for the RC-3a with the resistor 3. Charge occurs until the voltage on the capacitor reaches the trigger level of the threshold amplifier, which triggers the tripping winding 2.

The key-driver of the charging pulse generates a charging pulse of constant duration (on the order of 20 ms), independent of the closing time of the start switch 7 and always prepared for a new cycle after the end of the previous one, since during the time delay the capacitor 11 is discharged to the resistor 10 and the key is ready to form a new impulse. Zener diode 9 is designed to stabilize the pulse duration.

Claims (2)

1. USSR author's certificate number 598, cl. And 03 K 17/18, 1978. 2. USSR author's certificate No. 508818, cl. H 01 And 47/18, 10.01.73 (prototype).