Question

1. A 4 pole, 220 V, 10 H.P, d.c. shunt motor is rotating at a speed of 320 rpm. Then the developed useful torque is

a.210.647 N-m

b.215.547 N-m

c.219.484 N-m

d.None of these

2. A 4 pole, lap wound d.c. motor drawing an armature current of 20 A has 360 conductors. If the flux per pole is

0.015 Wb then the gross torque developed by the armature of motor is

a.10.23 N-m

b.15.56 N-m

c.17.17 N-m

d.19.08 N-m

3. A 240 V, 17 kW d.c. shunt motor draws an armature current of 80 A at full load. The armature and shunt field

resistances are 0.2 ohm and 195 ohm respectively. The

efficiency of motor at full load is

a.87.20 %

b.89.32 %

c.89.67 %

d.90.03 %

4. A 240 V, 17 kW d.c. shunt motor draws an armature current of 80 A at full load. The armature and shunt field resistances are 0.2 ohm and 195 ohm respectively. The rotational mechanical losses at full load is

a.640 W

b.920 W

c.1080 W

d.1200 W

Answer 1