1. In DC chopper, the waveform for input and output voltages is respectively __________
A. Discontinuous and Continuous
B. Continuous and Discontinuous
C. Both continuous
D. Both discontinuous
2. A chopper behaves as a __________
A. DC equivalent of AC switching device
B. DC equivalent of AC transformer
C. DC equivalent of AC relay
D. AC equivalent of circuit breaker
3. A DC chopper feeds an RLE load. If the value of E is increased by 20%, the current ripple ________
A. increases by 20%
B. decreases by 20%
C. increases only 20%
D. remains the same
4. The conduction loss versus device current characteristic of a power MOSFET is best approximated by a ________
A. Straight line
B. Rectangular hyperbola
D. Exponential decaying functions
5. Which of the following device is NOT suitable for parallel operation?
6. SCR is uni-directional in nature.
7. Which of the following device should be used as a switch in a low power switched-mode power supply (SMPS)?
8. The slope of the V-I curve is 78°. Calculate the value of resistance. Assume the relationship between voltage and current is a straight line.
A. 4.732 Ω
B. 4.608 Ω
C. 4.543 Ω
D. 4.648 Ω
9. Calculate mark to space ratio if the system is on for 17 sec and the time period is 30 sec.
10. Turn-on and turn-off times of transistor depend on _________
A. Static Characteristic
B. Junction Capacitance
C. Current Gain
D. Voltage Gain
11. The generated e.m.f from 45-pole armature having 400 turns driven at 70 rev/sec having flux per pole as 90 mWb, with 17 parallel paths is ___________
A. 13341.17 V
B. 12370.14 V
C. 14700.89 V
D. 15690.54 V
12. The unit of Magnetic flux density is Tesla.
13. Calculate the moment of inertia of the hollow cylinder having a mass of 78 kg and a radius of 49 cm.
A. 9.363 kgm2
B. 9.265 kgm2
C. 9.787 kgm2
D. 9.568 kgm2
14. Calculate the value of the angular acceleration of the motor using the given data: J = 81 kg-m2, load torque = 74 N-m, motor torque = 89 N-m.
A. .195 rad/s2
B. .182 rad/s2
C. .183 rad/s2
D. .185 rad/s2
15. 340 V, 45 A, 1400 rpm DC separately excited motor having a resistance of .7 ohm excited by an external dc voltage source of 90 V. Calculate the torque developed by the motor on full load.
A. 94.73 N-m
B. 94.52 N-m
C. 93.37 N-m
D. 94.42 N-m