engineering recuitment GATE EE 2023-24 Test Series Power Electronics and Drives Phase Controlled Rectifiers Three Phase Thyristor Converter Circuits
A three-phase fully controlled converter operates from a 3 phase 230 V, 50 HZ supply through a transformer to supply a 220 V, 600 rpm, 500 A separately excited DC motor. The motor has an armature resistance of 0.02 Ω. The converter produces a rated motor terminal voltage at a 0° firing angle. Assume continuous conduction. The converter is used to brake the motor regeneratively in the reverse direction.
If the thyristors are to be provided with a minimum turn off time of 100 μs, which of the following is/are true?1
Turns ratio of the transformer is 1.41
2
Maximum value of the firing angle is 178.2°
3
Maximum negative voltage that can be generated by the converter is -219.89 V
4
Secondary line voltage of the transformer is 94 V