131. With the increase in supply frequency_________ decrease.
- starting current
- starting torque
- full load current
- maximum running torque
- starting and full load currents and starting and maximum running torque
132. The size of a high-speed motor is _______ in comparison to that of a low-speed motor or the same KW output.
- smaller
- larger
- almost the same
- unpredictable
133. For starting a 3-phase induction motor _______ wining is to be connected to 3-phase ac supply.
- rotor
- stator
- both stator and rotor
- none
134. The starting current of a 3-phase induction motor is about _______ of its full-load rated current.
- half
- twice
- 5 to 7 times
- 15 to 20 times
135. The purpose of the starter is to,
- Limit the starting current
- Limit the speed
- Protect against overvoltage
- Produce back emf
136. The following starting method for an induction motor is inferior from the point of view of poor starting torque per ampere of the line current drawn
- Direct-on-line starting
- Auto-transformer method of starting
- Series inductor motor of starting
- Star-delta method of starting
137. Direct- on-line starters can be used for small capacity _______ induction motors.
- squirrel cage
- wound rotor
- squirrel cage and wound rotor both types of
138. Induction motors, when directly switched on across their normal rated supply voltage, the torque developed at starting is about _______ of their full load torque.
- half
- 1.5 to 2.5 times
- 5 times
- 10 times
139. Under which of the following starting methods, an induction motor draws the largest starting current.
- Star-delta starting
- Auto-transformer starting
- Direct-on-line starting
- Reduced voltage starting
140. _______starter is used for starting a 3-phase induction motor that needs frequent starting and starting and operating in forward and reverse directions.
- Direct-on-line
- Star-delta
- Auto-transformer
- Reduced voltage