121. Slip-ring induction motors have the advantages of
- high starting torque and high overload capacity
- nearly constant speed
- low starting current in comparison to squirrel cage induction motor
- All of the above
122. Slip-ring motors have the disadvantage of
- low efficiency and low power factor in comparison to squirrel cage induction motors
- low power factor at light load
- sensitivity to fluctuations in supply voltage
- all of the above
123. For high starting torque, the most suitable three phase induction motor is _________ induction motor
- slip-ring
- squirrel cage
- double cage
- deep bar squirrel cage
124. Which of the following ac motor is widely used?
- Squirrel cage induction motor
- Slip-ring induction motor
- Double cage induction motor
- Synchronous motor
125. A squirrel cage induction motor is not favored when _________ is the main consideration.
- initial cost
- maintenance cost
- high starting torque
- higher efficiency and higher power factor
126. A slip-ring induction motor is recommended for applications requiring
- high starting torque
- variable speed operation
- frequent starting, stopping, and reversing operations
- all of the above features
127. Induction motors, over synchronous motors, have the advantages of
- being self-starting
- having no requirement for dc excitation
- possibility of speed control to small extent
- simplicity and lower cost
- all of the above
128. Unbalanced supply voltage given to a 3-phase, delta-connected induction motor will cause
- Zero sequence currents
- Less heating of motor
- Negative sequence component current
- Al the above
129. Increase in supply voltage to three phase induction motor will not cause
- decrease in input current and so reduction in copper losses
- increase in torque
- decrease in speed as well as in core loss
- operating temperature abnormally higher owing to increase in core loss
130. A squirrel cage induction motor having a rated slip of 4% of full load has a starting torque same as the full load torque. Which one of the following statement is correct/ the starting current is
- Equal to the full-load current
- Twice the full-load current
- Four times the full load current
- Five times the full-load current