SU898566A1 - Device for switching-on parallel-connected thyristors - Google Patents

Description

(5) DEVICE TO INCLUDE PARALLELALLY CONNECTED TYRISTORS

one

The device relates to electrical engineering and can be used in automation systems, where source protection should be ensured at overload currents at the moment of switching on the thyristors.

A device is known for switching parallel-connected thyristors, the control electrodes of which are connected via a switch to a source of constant voltage 1.

However, in these devices, the turn-on time of each subsequent thyristor increases, and, moreover, the source is not protected against overload at the moment the load is connected to the source.

Closest to the present invention is a device for switching parallel-connected thyristors, the control electrodes of which are connected to the terminals of the resistors, containing a switch for switching on the thyristors, diodes connected in series

With each thyristor, and capacitors, one plate connected to the common point of the diode and the thyristor, and the other plate - to the power source 23. This device reduced the turn-on time of the thyristors, but it does not protect the source from overload at the moment the load is connected to the source.

The aim of the invention is to extend the functionality by controlling the load circuit mode,

This goal is achieved by the fact that the device is equipped with a capacitor and a capacitor discharge element, the capacitor being connected parallel to the capacitor discharge element between the cathodes of the diodes and the positive source bus Through a key, and the second terminals of the resistors are connected to the cathodes of the diodes.

Claims (2)

The element of the discharge is made by the indicator. . 389 The drawing shows the scheme of the device. Serial circuits from thyristor 1 and diode 2, thyristor 3 and diode k are connected in parallel to one FRIEND and successively to the load circuit 5 between pin 6 and 7 of the power supply of the constant voltage source. The capacitors 8 and 9 are connected between the thyristor cathodes and the power supply bus 7. Resistors 10 and 11 are connected between the control electrodes of the thyristors and the cathodes of the diodes, and through a parallel connected capacitor 12 and an overload indicator 13, for example, a glow lamp, and through the key 1 are connected to the positive bus 6 source of Kitani. When powered on. Bus 6 and 7 polarity indicated on the drawing, the current to the load circuit does not flow. When the key 14 is closed, a current flows through the capacitor 12 and the indicator 13 to the load circuit 5. If the resistance does not change to a critical value in the load circuit before it is connected to the positive bus 6 of the source, then the voltage drop across the load 5 generates the thyristor switching currents, they turn on, shunt elements 12 and 13. If the load resistance became critical, then load-5, the voltage drop is not enough to turn on the thyristors, since they do not turn on; then when the capacitor 12 is charged on the indicator 13, a voltage is formed that provides an indicator to light up, indicating an alarm condition in the circuit shipments. The voltage drop across the indicator is provided by the ratio of the resistance of the load circuit to the resistance of the indicator and the smaller it is, the greater the voltage drop across the overload indicator. Thus, the proposed device controls the load circuit at the moment of switching on and has an alarm about the thyristor operation mode. Claim 1. Device for switching parallel-connected thyristors, control electrodes of which are connected To the terminals of resistors, containing a switch for switching on thyristors, diodes connected in series with each thyristor, and capacitors, one plate connected to the common point of the diode and the thyristor, and the other facing - to a power source that differs from the fact that, in order to expand its functionality by controlling the load circuit mode, it is equipped with a capacitor and a capacitor discharge element, and a capacitor element connected in parallel with the capacitor discharge between the cathodes of diodes and the positive bus via the source key, and the second terminals of the resistors are connected to the cathodes of diodes. 2, The device according to A.1, in that the discharge element is made by the indicator. Sources of information taken into account in the examination 1.Patent of Switzerland No. 13933, cl. 21 d 12/04, 1964. 2. USSR author's certificate ff 675.552, cl. H 02 M 1/08, 1978.