SU573385A1 - Apparatus for electrical braking of ac electrically-driven rolling stock - Google Patents

Description

This invention relates to electrical equipment of an electroprotective alternating current composition with recuperative electrical braking.

There are known devices for regenerative braking on alternating current, in which the parapet groups of the windings of the crank motors are included in the rectified current circuit of the thyristor converter through stabilizing resistors, and the windings are excited in series and fed to a separate section of the secondary winding of the flj transformer.

It is also known a device for electric braking of an alternating current electric rolling stock containing a triristor converter connected to a transformer with a smoothing reactor and direct current traction motors with windings of the core and excitation windings connected in a circuit with brake diagonal included resistor 2.

In the known device, the windings of the core and the windings of the excitation of the traction direct-current drivers with series excitation are cross-connected by a bridge circuit. In such a circuit, a large number of contacts are required to control the deceleration rate and a higher braking resistor power. In addition, in the zone of low speed the rigidity of the braking characteristics is not provided.

The aim of the invention is to increase the stability of the braking mode.

This is achieved by the fact that the braking resistor is connected to the poles of the direct current of the thyristor converter.

The drawing shows a circuit diagram of the device.

A device for electric braking of windings 1 and 2 of the core of windings 3 and 4 of excitation of traction engines, connected crosswise by bridge circuit.

Claims (2)

A rectifier-inverter thyristor converter with thyristor arms 5-8 and a transformer 9 are included in the diagonal of the bridge circuit. The Yun braking resistor and smoothing reactor 11 are connected through a normally closed contactor 12. The device operates as follows. The traction motors are self-excited by residual magnetic flux and the current flows through the ephemeral circuit 1, 4, 12, 10 and 11. The process of self-excitation of the traction motors is accelerated by the current consumed from the traction network when the thyristors are opened during the reverse half-phase voltage of the transformer 9. The current of this current is determined by the angle of the inversion margin. The current is directed according to the emf. the secondary winding of the transformer 9 and flows through the circuit of elements 1, 4, 5, 9, 8 and 11. At the 9.D.S. windings 1 and 2 of the core greater 9.DS.S. transformer 9, on-chip converter & The driver goes to the inverter mode. The current is directed counter voltage the secondary winding of the transformer 9 and flows through the cisch of elements 1, 4, b, 9, 7 and 11. At a small movement speed, the thyristor converter switches to the rectifying mode and the stop braking is performed. Current flows through the circuit of elements 14598 and 11. In reducing the electrical losses in the rectifying mode, the braking resistor 10 is switched off by the contactor 12-. The change in the speed of movement of the electric rolling stock during braking is performed by adjusting the angle of unlocking the thyristors of the converter. The electrical braking stability is achieved not only by the cross-connection of the windings of the traction motors, but also by using a braking resistor connected in parallel with the output of the thyristor converter, so that a constant emf is maintained on the thyristor converter At a high speed of movement of the electric rolling stock, switching commutators is improved by reducing the current ripple and the amplitude of the current flowing by the traction motors during a short circuit when the inverter mode is tilted decreases. Similarly current flows in the circuit of another engine. The device, by switching on the rectifier-inverter thyristor converter into the diagonal of the bridge circuit, makes it possible to significantly reduce the power of the braking resistor, to transfer electrical energy to the traction network, and also to reject the excess electrical equipment. which is on the electric rolling stock by regenerative braking with the independent excitation of the traction engines. Claims An apparatus for electric braking of an alternating current electric rolling stock containing a thyristor converter connected to a transformer with a floating reactor and direct current traction motors with windings of the core and excitation windings connected in a bridge circuit, the diagonal of which includes a braking resistor that differs from that, in order to improve the stability of the braking mode, the braking resistor is connected to the poles of a direct current thyristor converter. Sources of information taken into account in the examination: 1. B. Tikhmenev, N., M. Trakhtman. Rolling stock of electric railways. M .. Transport, 1969. p. 182-184. 2. Tikhmenev BM, Trakhtman LM. Rolling stock of electric railways, M., Transport, 1969, p. 139.