SU735459A1 - Apparatus for rheostatic braking of d.c. motor - Google Patents

Description

(54) DEVICE FOR RELIABLE BRAKING OF DC MOTOR

The invention relates to railway transport, in liacTHOCTH / to devices for resistive braking of direct current motors of electric rolling stock equipped with thyristor-pulse interrupters.

A device for resistive braking of a direct current motor is known, which contains a thyristor interrupter, the main thyristor of which is connected to the neutral core, and the switching circuit is connected through the core winding and the braking resistor to the source, power, and reverse diodes, one of which shunts the core winding and the brake reznetor 1.

The disadvantage of the device is that the minimum short circuit time of the motor core to the excitation winding. it determines the recharge time of the switching capacitor, and this does not allow to reduce the magnitude of the excitation current below a certain value, which limits the maximum value of the rate of the onset of braking.

The purpose of the invention is to increase the speed limit of the start of braking.

The goal is achieved by the fact that the motor excitation winding is shunted with another reverse diode and connected in parallel with the winding of the core with the help of a main thyristor, the anode of which is connected to the 5 excitation winding and the cathode with the winding of the core.

The drawing shows a circuit diagram of the device.

The main thyristor 1 of the chopper is connected by a cathode to the winding 2 of the engine core 10 and the anode to the excitation winding 3 driven by a reverse diode 4. The auxiliary thyristor 5 of the remote switching circuit including the capacitor 6 and the restart choke 7 is connected to the plus terminal 8 nutrition A braking resistor 9 is connected between the terminal "minus the power supply 8 and the winding 2 core and shunted along with it with another reverse diode 10.

The device works as follows.

The motor excitation winding is reversed for the transition from the electric resistor braking mode. Therefore, the emf of engine rotation is directed according to the voltage of the primary power source. Before supplying the trigger pulses to the thyristors of the chopper, the switching capacitor 6 through the winding 2 core and the braking resistor 9 is charged before the voltage of the power source is polarity indicated in the drawing. When under control, the auxiliary thyristor 5 is merged, and then the direct oscillatory recharge of commutating capacitor 6 begins on the circuit 6-5-7-6 From the source to the circuit: terminal "plus source 8 - 5-2-9 - terminal "Minus source 8 through the winding 2 core flows a current limited by the braking resistor 9. When the de-coupling capacitor 6 is re-charged, the auxiliary thyristor 5 is locked, and after the recharging has ended, the EMF of the core winding maintains a current in the circuit 2-9-10-2 . . The motor's initial self-excitation current appears when the main thyristor 1 is unlocked. After unlocking the main thyristor 1, the motor is short-circuited, which leads to an intense increase in the current in circuit 2-3-1-2. The main thyristor 1 is locked in the same way as the auxiliary thyristor 5 during the reverse recharge of the switching capacitor. The auxiliary thyristor 5 is each time unlocked at the end of the operating cycle. By adjusting the time of unlocking the main thyristor relative to the moment of the beginning of the reverse reloading of the switching capacitor, the connection time of the excitation winding to the EMF of the rotation of the core can be made arbitrarily small, i.e. get any minimum required value of the excitation current. As the speed of rotation of the CG GSr DvGetey 7ve-Mchiv eTy-oop; P Waiting for the moment of unlocking the main thyristor 1 by retrospect by the time of the beginning

reverse reload) 1a switching capacitor 6..i

After both the thyristors shut off and the switching capacitor is reversed, the current core, decay, closes the circuit 2-9-10-2, and the excitation winding closes through the reverse diode 4.

Claims (1)

Thus, the proposed device makes it possible to provide a reliable powering of the engine during the transition to the generator mode due to the energy consumed directly from the primary source. It can be used to extend the range of regulation of the excitation current of the engine, which, in turn, allows an increase in the limiting speed of the start of braking. It can be implemented on an electric rolling stock of direct current, equipped with thyristor pulse control. Claim I A device for resistive motor braking with a constant current comprising a thyristor interrupter, the main thyristor of which is connected to the core winding, and the switching circuit is connected through the core winding and the braking resistor with a power source, and reverse diodes, one of which touches the core winding A braking resistor, characterized in that, in order to increase the limiting speed of the onset of braking, the motor excitation winding is clamped by another reverse diode and connected in parallel with the winding of the core schyu main thyristor, whose anode is connected to the excitation winding, and the cathode - to the armature winding. Sources of information taken into account in the examination, 1. USSR Author's Certificate No. 426889, cl. B 60 L 7/16, 21.12.72.