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.Management Sciences
Category: Power Electronics
Which following is a two terminal three layer device?
A. BJT
B. Power dioed
C. MOSFET
D. None of above
In a 3 phase VSI SPWM to use a single carrier signal and preserve the features of PWM technique, the normalized carrier frequency should be____________?
A. Multiple of two
B. Odd multiple of three
C. Odd multiple of five
D. Odd multiple of seven
A TRIAC can be turned on with______________?
A. Positive voltage at the gate terminal
B. Negative voltage at the gate terminal
C. Either (a) or (b)
D. None of these
For commutation in three phase PAC, normally balanced three phase voltages VR, VY and VB are connected to the three legs of the converter via______________?
A. Three inductances
B. Three capacitances
C. Three resistance
D. Three transistors
If a shunt motor is started with its field winding open then___________?
A. It will rotate at the same speed as that with its field winding closed
B. It will rotate at less speed as that with its field winding closed
C. It will rotate at dangerously high speed
D. None of these
Silicon controlled rectifier can be turned on____________?
A. By applying a gate pulse and turned off only when current becomes zero
B. And turned off by applying gate pulse
C. By applying a gate pulse and turned off by removing the gate pulse
D. By making current non zero and turned off by making current zero
In a three phase voltage source inverters____________?
A. Only amplitude of voltage is controllable
B. Only phase is controllable
C. Both amplitude and phase is controllable
D. Amplitude, phase and frequency of voltages should always be controllable
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