1
GATE EE 1995
Numerical
+1
-0
A three phase $$ac$$-to-$$dc$$ diode bridge rectifier is supplied from a three-phase, $$440V$$ source. The rectifier supplies a purely resistive load. The average $$dc$$ voltage across the load will be ___________ $$V$$.
Your input ____
2
GATE EE 1995
MCQ (Single Correct Answer)
+1
-0.3
A single phase diode bridge rectifier supplies a highly inductive load. The load current can be assumed to be ripple free. The ac supply side current waveform will be:
A
sinusoidal
B
constant dc
C
square
D
triangular
3
GATE EE 1995
MCQ (Single Correct Answer)
+1
-0.3
A $$dc$$ to $$dc$$ transistor chopper supplied from a fixed voltage $$dc$$ source feeds a fixed resistive-inductive load and a free-wheeling diode. The chopper operates at $$1$$ $$kHz$$ and $$50$$% duty cycle. Without changing the value of the average $$dc$$ current through the load, if it is desired to reduce the ripple content of load current, the control action needed will be
A
Increase the chopper frequency keeping its duty cycle constant
B
Increase the chopper frequency and duty cycle in equal ratio
C
Decrease only the chopper frequency
D
Decrease only the duty cycle.
4
GATE EE 1995
MCQ (Single Correct Answer)
+1
-0.3
An inverter capable of supplying a balanced three - phase variable voltage variable frequency output is feeding a three - phase induction motor rated for $$50$$ $$Hz$$ and $$440V.$$ The stator winding resistances of the motor are negligible small. During starting, the current inrush can be avoided without sacrificing the starting torque by suitably applying.
A
Low voltage at rated frequency
B
Low voltage keeping the $$V/f$$ ratio constant
C
Rated voltage at low frequency
D
Rated voltage at rated frequency
EXAM MAP