111. Skew of rotor bar eliminates
- the effect of space harmonics
- the entire effect of crawling
- magnetic noise
- vibration due to unequal force developed on rotor
112. Cogging of an induction motor is
- energizing a motor once or repeatedly to have small movements or mechanisms
- a process of synchronization
- a method of braking
- none of the above
113. In a squirrel cage induction motor high starting torque is achieved by using
- high resistance in series with the rotor circuit
- low resistance across the rotor circuit
- double cage rotor
- none of these
114. The outer cage of a double squirrel rotor consists of
- manganese brass
- red copper
- bronze
- steel
115. In the equivalent circuit of a double-cage induction motor, the two rotor cages can be considered
- to be in parallel
- to be in series-parallel
- to be in series
- to be in parallel with stator
116. The advantage of the double squirrel-cage induction motor over single cage rotor is that its
- efficiency is higher
- power factor is higher
- slip is larger
- starting current is lower
117. In the double squirrel cage induction motor, the resistance of upper cage is ________ that of inner cage
- equal to
- 4 to 5 times of
- one-fourth of
- none of these
118. The deep-bar rotor or double cage rotors are employed to
- increase starting torque
- improve efficiency
- increase pull-out torque
- reduce rotor core loss
119. Squirrel cage induction motors have the advantages of
- cheaper in initial as well as in maintenance costs
- nearly constant speed, high overload capacity, simple starting arrangement and high power factor
- lower copper losses and higher operation efficiency
- all of the above
120. Squirrel cage induction motors have the disadvantage of
- higher starting current and poor starting torque
- high sensitivity to fluctuations in supply voltage and power factor at light-load
- no possibility of speed regulation
- all of the above