| 1. | The shaft of an induction motor is made of ? | |
|
high speed steel
|
||
|
stainless steel
|
||
|
carbon steel
|
||
|
cast iron
|
||
View Answer
Discuss in Forum
Report Question| 2. | In a three-phase induction motor, the number of poles in the rotor winding is always ? | |
|
zero
|
||
|
more than the number of poles in stator
|
||
|
less than number of poles in stator
|
||
|
equal to number of poles in stator
|
||
| 3. | It is advisable to avoid line starting of induction motor and use starter because ? | |
|
it will run in reverse direction
|
||
|
it will pick up very high speed and may go out of step
|
||
|
motor takes five to seven times its full-load current
|
||
|
starting torque is very high
|
||
| 4. | The torque developed by a 3-phase induction motor least depends on ? | |
|
rotor current
|
||
|
rotor power factor
|
||
|
rotor e.m.f.
|
||
|
shaft diameter
|
||
| 5. | If s is the slip and f is the supply frequency, the frequency of rotor current is given by ? | |
|
s.f
|
||
|
s2f
|
||
|
s.f/2
|
||
|
f/s
|
||
| 6. | In an induction motor the relationship between stator slots and rotor slots is that ? | |
|
stator slots are equal to rotor slots
|
||
|
stator slots are exact multiple of rotor slots
|
||
|
stator slots are not exact multiple of rotor slots
|
||
|
none of the above
|
||
| 7. | In medium sized induction motors, the slip is generally around ? | |
|
0.04%
|
||
|
0.4%
|
||
|
4%
|
||
|
14%
|
||
| 8. | The torque developed by a 3-phase induction motor least depends on ? | |
|
rotor current
|
||
|
rotor power factor
|
||
|
rotor e.m.f.
|
||
|
shaft diameter
|
||