Assertion (A): A dual converter may be circulating current type or non circulating current type.
Reason (R): In circulating current dual converter only one converter can be operated at one time.
Answer: C
In circulating current dual converter both converters operate together.
Enter details here
In controlled heating circuits, thyristors act as
Answer: C
The output voltage is controlled ac.
Enter details here
In a 3 phase full converter the average load current is 150 A. The average thyristor current is
Answer: C
Each thyristor conducts for one-third of one cycle.
Enter details here
During forward blocking state of SCR, the voltage and current respectively are
Answer: C
Voltage is high but current is nearly zero.
Enter details here
Which of these commutation methods uses an auxiliary SCR?
Answer: C
Class C commutation uses an auxiliary SCR and it is also called auxiliary commutation
Enter details here
HVDC transmission systems generally use
Answer: A
To reduce ripple, 12 pulse converters are used in HVDC.
Enter details here
HVDC transmission systems generally use
Answer: A
To reduce ripple, 12 pulse converters are used in HVDC.
Enter details here
A 3 phase induction motor is controlled by voltage and frequency control such that the ratio V/f is constant. At 50 Hz, the speed is 1440 rpm. At 25 Hz, the speed is likely to be
Answer: B
In this case synchronous speed at 50 Hz is 1500 rpm. Therefore synchronous speed at 25 Hz is 750 rpm. Since slip is about 3 - 5%, speed is about 720 rpm.
Enter details here
In 180° mode of operation of a 3 phase bridge inverter, two thyristors conduct at one time.
Answer: B
In 180° mode three thyristors conduct simultaneously.
Enter details here
Thyristors are suitable for dc circuit breakers but not for ac circuit breakers.
Answer: B
They are suitable for both dc and ac circuit breakers.
Enter details here