Power Electronics
Choppers and Commutation Techniques
Marks 1Marks 2Marks 5
Single and Three Phase Rectifier
Marks 1Marks 2Marks 5
Power Semiconductor Devices
Marks 1Marks 2
Ac Voltage Controllers
Marks 1Marks 2Marks 5
1
GATE EE 1995
Numerical
+1
-0
Consider the chopper circuit of figure. The chopper operates at $$400$$ $$Hz$$ and $$50$$% duty cycle. The load current remains almost ripple free at $$10A.$$ Assuming the input voltage to be $$200V$$ and the devices to be ideal, the turn-off time available to the thyristor $$Th$$ $$M$$ is____________ $$\mu s$$ GATE EE 1995 Power Electronics - Choppers and Commutation Techniques Question 44 English
Your input ____
2
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.
3
GATE EE 1994
Subjective
+1
-0
Match the following

List $$-$$ $${\rm I}$$
$$A.$$ Commutation
$$B.$$ $$V$$ $$-$$ Curves
$$C.$$ Free wheeling diode
$$D.$$ Overlap

List $$-$$ $${\rm II}$$
$$P.$$ Resistive load
$$Q.$$ Inductive load
$$R.$$ Capacitive load
$$S.$$ Inter pole
$$T.$$ Source Inductance
$$U.$$ Synchronous motor

4
GATE EE 1993
MCQ (Single Correct Answer)
+1
-0.3
A chopper operating at a fixed frequency is feeding an $$R$$-$$L$$ load. As the duty ratio of the chopper is increased from $$25\% $$ to $$75\% $$, the ripple in the load current
A
Remains constant
B
Decreases, reaches a minimum at $$50\% $$ duty ratio and then increases
C
Increases, reaches a maximum at $$50\% $$ duty ratio and then decreases
D
Keeps on increasing as the duty ratio is increased
GATE EE Subjects
Electromagnetic Fields
Signals and Systems
Engineering Mathematics
General Aptitude
Power Electronics
Power System Analysis
Analog Electronics
Control Systems
Digital Electronics
Electrical Machines
Electric Circuits
Electrical and Electronics Measurement