1 (a)
Explain significance of back emf in DC motor.

5 M

1 (b)
Draw the block diagram and explain v/f control using converter inverter scheme for 3 phase induction motor.

5 M

1 (c)
A 230V D.C. motor has an armature circuit resistance of 0.6Ω if the full load armature current is 30A and no-load armature current is 4A. Find th change in back emf from no load to full load.

5 M

2 (a)
Draw and explain 3-point starter of DC shunt motor.

7 M

2 (b)
A 6-pole lap wound shunt motor has 500 conductors the armature and shunt Filed resistance are 0.5 Ω and 25 Ω respectively, find the speed of the motor if it takes 120 A from a DC supply of 100V. Flux per pole is 20mWb.

8 M

3 (a)
Explain construction and working of 3 phase squirrel cage induction motor.

8 M

3 (b)
Draw and explain torque speed characteristics of 3 phase induction motor.

7 M

4 (a)
Explain in detail different starting methods of single phase induction motor.

7 M

4 (b)
A 600W, 115V, 60Hz capacitor start motor draw 13.8 A from the supply at rated load if the efficiency is 65% and rated speed is 1750 RPM, calculate

i) Input power at rated load

ii) Power Factor at rated load

iii) Rated motor horse power.

i) Input power at rated load

ii) Power Factor at rated load

iii) Rated motor horse power.

8 M

5 (a)
Classify the brushless DC motor and explain in detail unipolar brushless DC motor.

7 M

5 (b)
Explain construction, working and control requirements of switched reluctance motor.

8 M

Write short notes on :-

6 (a)
Star-Delta starter of 3 phase induction motor.

5 M

6 (b)
Different speed control methods of DC shunt motor.

5 M

6 (c)
Explain the double field revolving theory in single phase induction motor.

5 M

More question papers from Electrical Machines