SU119197A1 - Device for zero protection of traction engines - Google Patents

Description

The known devices for zero protection of the traction motors of the electric rolling stock of direct current are based on the use of relay circuits.

The proposed device is more perfect as it prevents damage to the engines in the weak field mode.

This is due to the fact that the normally open contact of the contactors interrupting under the action of the indicated relay circuit, which is triggered by a loss of power or an unacceptable voltage drop in the contact circuit, is connected to the ohmic resistance circuit shunting the motor field winding and weakening its field.

The drawing shows the power circuit of the proposed device.

The null protection of the motor is carried out using a relay circuit consisting of two relays 2 and 3 of the usual type. The normally open contacts of these relays are included in the coil circuit of the contactor 4, which connects in the field weakening mode parallel to the excitation latch of 5 t engine motor / bypass resistance 6. If the power is lost or the voltage in the contact network is inadmissible, the relay circuit is activated and the contactor 4 is turned off, the circuit is open shunt resistance 6. When using such a device, inductive shunts can be removed from the electric locomotive scheme without harmful consequences for traction engines.

Subject invention

The device for zero protection of the traction motors of an electric current composition of direct current using a relay circuit, characterized in that, in order to prevent damage to the motors when operating in a weak field mode, normally open contactors of contacts are opened in the shunt excitation winding circuit the action of the specified relay circuit, triggered by loss of power or unacceptable voltage drop in the contact network.