SU612408A1 - Switching apparatus - Google Patents

Description

(54) KEY

The output of power during the transient process of switching on the load 7 takes place on the thyristor 2, which well withstands the pulsed loads of the pi current. It is known that the turn-on currents of electromagnets and electric motors exceed their current in established modes.

When the control voltage is removed, the transistor 4 is locked, as a result of which the control circuit, its thyristor 2 electrode, is disconnected, the load 7 is disconnected, and when the current through the thyristor 2 becomes less than the value Ts, the latter closes, after which is chosen less than the reverse resistance of diode 3 and transistor 4, shunts the latter, as a result of which the entire voltage of the locked key is applied to the thyristor 2. The operating mode of transistor 4 is pulsed, since a high voltage is applied to mu only at the time of turn-off transient key. In a pulsed mode, current high-voltage transistors withstand voltages above 1 kV.

Thus, the key is turned on by the thyristor, which withstands the overcurrent well, the trip by the transistor, the trip time of which does not depend on the phase

of the supply voltage, and the duration of the disconnection of the load 7 is determined by the disconnection time of the transistor 4 and is ten

microseconds

Claims (2)

1. Dzjubin I.I. Lockable thyristors and their application. M., “Energie, 1976, p. 19-20. 2. Brufman S. S. and Trofimov N. A. Thyristor switches of alternating current, M., 5 “Energie, 1969, p. 9.