Power Electronics Questions

• The terminals of a power MOSFET are called
• In a 3 phase fully controlled converter the firing frequency is
• In a single phase full wave regulator, the firing angles in the positive and negative half cycles are generally
• The dynamic equalising circuit consists of a series combination of capacitor C and resistor RC across each thyristor. This resistance RC (along with parallel connected diode)
• A dc separately excited motor has constant field current. The armature is fed from a single phase supply through a full converter. When a = 0, speed is 500 rpm. If a = 45°, the speed is likely to be
• Two thyristor of same rating and same specifications
• In single phase half wave regulator, the average current over one full cycle
• Thyristors are suitable for dc circuit breakers but not for ac circuit breakers.
• If duty cycle is a and the load is a resistance R, the rms value of output voltage is
• The amount of dielectric heating is inversely proportional to frequency.
• A thyristor needs protection against
• All inverters use forced commutation.
• 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.
• The two modes of operation of three phase bridge inverters are known as
• A single phase step up cycloconverter changes 50 Hz to 100 Hz. Then one half wave of input will give rise to
• The number of doped regions in a SCR is
• A dc circuit breaker must use
• In a full wave converter (M - 2 connection) feeding an RLE load, the peak thyristor current is 15 A. For fully controlled bridge circuit and same load current, the peak thyristor current will be
• If ton and toff are the turn on and turn off times of a thyristor, then
• In 180° mode of operation of a 3 phase bridge inverter, two thyristors conduct at one time.