Q. In a 3 phase semiconverter, the firing frequency is

View solution

Q. Present day HVDC converters are all

View solution

Q. A single phase full converter gives maximum and minimum output voltage at firing angles of

View solution

Q. A thyristor has its gate current zero. To start conduction the forward voltage must exceed

View solution

Q. Assertion (A): Snubber circuit has an RC series circuit in parallel with SCR

Reason (R): Voltage across a capacitor can not change instantaneously.

View solution

Q. In dielectric heating, the thyristor circuits consist of

View solution

Q. On load tap changer using thyristors can have a maximum of two taps.

View solution

Q. Assertion (A): A cycloconverter may be line commutated or forced commutated

Reason (R): A step up cycloconverter requires forced commutation.

View solution

Q. When thyristors are connected in series and parallel, it may be necessary to have :

View solution

Q. A single phase half wave regulator uses

View solution

Q. A Shockley diode can be used

View solution

Q. An SCR has a turn on time of 4 μs. The gate pulse should have a duration of about

View solution

Q. In a multiphase chopper, the different choppers operate in

View solution

Q. In a dual converter both converters work as rectifiers.

View solution

Q. A single phase full wave regulator feeds R-L load. The best gating signal is

View solution

Q. A 3 phase induction motor is fed by a 3 phase ac regulator to change the stator voltage. The variation in speed will be more if

View solution

Q. A cycloconverter cannot give a frequency higher than input frequency.

View solution

Q. A thyristor has internal power dissipation of 40W and is operated at an ambient temperature of 20°C. If thermal resistance is 1.6° C/W, the junction temperature is

View solution

Q. In a single phase dual converter, α1, and α2 are firing angles of the two converters. Then

View solution

Q. The number of gates in an SCR is

View solution