SU367551A1 - TIME RELAY - Google Patents

Description

one

The invention relates to the field of automation and telemechanics.

There are known time relays on a thyristor, in the cathode circuit of which a bridge is inserted, containing in (Levers resistors an output voltage divider,: a capacitor and a resistor of the master / C-circuit, and in a diagonal - emitter junction - base of the transistor.

However, the recovery time of the known time relays is long, since it is the sum of the capacitor discharge time and the auxiliary thyristor off time.

The purpose of the invention is to reduce the recovery time. This is achieved by connecting the collector of the transistor to the control electrode of the thyristor.

The drawing shows a schematic diagram of the proposed time relay.

In the initial state, the two-step thyristor / stuck, the capacitor 2 is discharged, and all the electrodes of the transistor 3 have almost zero potential. Before the input pulse arrives, the circuit does not consume current.

A positive input pulse unlocks the thyristor 1, and the voltage of the power source E is applied to the load. On the emitter of transistor 3 | a certain positive potential is fixed, the value of which is determined by the resistances of resistors 4 and 5 of the output voltage divider. Capacitor 2 is charged through time by drive resistor 6.

When the voltage across the capacitor 2 reaches the emitter potential of the transistor 3,

the latter opens and connects the control electrode of the thyristor 1 through the resistor 5 to ground, which leads to the locking of the thyristor 1 (the collector current of the transistor 3 flows in the direction from the control electrode of the thyristor and therefore is the blocking current for the thyristor). The load is disconnected from the power source, and after the discharge of the capacitor 2 through the base-emitter junction of transistor 3 and the low-resistance resistor 5, the circuit returns to its original state.

When using a transistor that allows a small reverse voltage at the emitter-base junction, diode 7 is introduced into the circuit.

Subject invention

The time relay on the thyristor, in the cathode circuit of which a bridge is inserted, containing

The shoulders of the output voltage divider, the capacitor and the resistor of the master / C-circuit, and in the diagonal - emitter-base transition of the transistor, characterized in that, in order to reduce the recovery time, the collector of the transistor is connected to the control electrode of the thyristor.

entrance

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