AV,rpm,A separately-excited dc motor has an armature resistance of .5 ω. It is fed from single-phase full converter with an ac source voltage ofV, 50Hz. Assuming continuous conduction, the firing angle for rated motor torque at (-rpm is _________
a) 122.4°
b) 117.6°
c) 130.1°
d) 102.8°
Q.3.
The unit of angular acceleration is rad/s2.
a) True
b) False
Q.4.
Calculate the value of the angular acceleration of the motor using the given data: J=kg-mload torque =N-m, motor torque =N-m.
a) -.7 rad/s2
b) -.6 rad/s2
c) -.3 rad/s2
d) -.4 rad/s2
Q.5.
The principle of step-up chopper can be employed for the ________
a) Motoring mode
b) Regenerative mode
c) Plugging
d) Reverse motoring mode
Q.6.
A Buck-Boost converter is used to _________
a) Step down the voltage
b) Step up the voltage
c) Equalize the voltage
d) Step up and step down the voltage
Q.7.
Which of the following converter circuit operations will be unstable for a large duty cycle ratio?
a) Buck converter
b) Boost converter
c) Buck-Boost converter
d) Boost converter and Buck-Boost converter
Q.8.
Calculate the shaft power developed by a motor using the given data: Eb =and I =A. Assume frictional losses areW and windage losses areW.
a) 4000 W
b) 2000 W
c) 1000 W
d) 1500 W
Q.9.
Which one of the following devices have low power losses?
a) MOSFET
b) IGBT
c) SCR
d) BJT
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