SU764133A1 - Reversible switch with electrodynamic braking - Google Patents

Description

The invention relates to electrical engineering, in particular, to control circuits of direct current electric motors. The closest to the invention according to its technical essence and achieved result is a reversing switch containing a bridge circuit on power transistors of different polarity, diodes, control transistors and in addition, the power source on the transistor, which opens the bridge transistors for the flow of the braking current to the electric motor after the power is removed 1} Disadvantages, the device - the presence of an additional source The power supply, the need to maintain two power transistors of the bridge circuit in the open state of removing the power of the electric motor, which increases the power consumption and dissipation of the reversing switch. The purpose of the invention is to reduce the power consumed and dissipated by the reversing switch. The goal is achieved by the fact that a reversing switch by electrodynamic braking is co-; 1power bridge circuit on power transistors of different conductivity, two diodes, the cathodes of which are connected to the output for connecting the power source, and the anodes to the terminals for connecting the electric motor included in the bridge diagonal, the emitters of which are connected crosswise to the bases of the two first power transistors located symmetrically in different arms of the bridge circuit, the emitters of the two second power transistors are connected to the cathode of 1I diodes and through resistors with their bases, the terminals are connected Controls to the live signals through resistors are connected to the bases of the control transistors, additionally equipped with two resistors, two diodes and two transistors, the collectors of which are connected to the bases, the emitters through additional diodes to the collectors of two second power transistors and to the terminals for connection to the electric motor, the bases crosswise - to control transistor collectors and through additional resistors - to the bases of the same power transistors.

The drawing shows the electrical circuit of the reversing switch.

A reversing switch with electrically controlled braking contains a bridge circuit on power transistors 1-4 and diodes 5 and b, controllable transistors 7-9 and additional transistors 10 and 11.

In the absence of control signals at the inputs 12 and 13 of the reversing switch, all transistors are closed.

When a control signal arrives at input 12 or 13 and further through resistors 14 or 15 or at inputs 12 and 13, transistors 7.9, 1 and 4, or 9.2 and 3, or 7, and 4, respectively, open. In the latter case, the transistor 9 blocks the passage of the control signal through the input 13 to the base of the transistor 8.

Pairs of power transistors in the diagonally opposite arms of the bridge circuit. At the same time, the motor is in the conducting state, and the electric motor 16 pivots in rotation in the fifth or other direction. .

When the control signal is present, the motor 16 continues to rotate by inertia. The geyser uses my diode through diode 5 and powering resistors 17, 18, and diode 19 to the base-to-emitter i junction of transistor 11 or diode 6 and other parts. elements resistors 2.21 and dibd 22 to the base-emitter transition of the transistor 10. Transistor 11 or 10 otiry-. and the power transistor 3 or 1 is disconnected. The electrodynamic braking current flows through a circuit of diode 5, transistor 6 or diode 6, transistor 1. When the motor is stopped, the generated voltage disappears and the reverse switch TpiaH resistors are closed. Resistor 23 is damping.

Thus, an additional power source is required for motor braking, which reduces power consumption and dissipation.

Claims (1)

1. British Patent 1,424,776 Class. H 03 K 17/66, 1976. L