AC Machines UM 1

Which of the following is a major disadvantage of Squirrel cage Induction Motor?

• Less Rotor Weight

• Short circuited Rotor Bars

• No Slip Rings

• High Stator to Rotor Air Gap

Why is a squirrel cage induction motor preferred over wound rotor induction motor in most applications?

• Higher efficiency

• Lower cost

• Greater speed control

• Longer lifespan

What is the slip of an IM at the time of starting?

• 0

• 1

• 1500

• infinity

What happens to the rotor speed of a squirrel cage induction motor as the load increases?

• The rotor speed decreases

• The rotor speed remains constant

• The rotor speed increases

• The rotor speed becomes erratic

How do you increase the starting torques of an Induction Motor?

• By Increasing Stator Resistance

• By Increasing Rotor Resistance

• By number of poles

• by reducing rotor impedance

What is the purpose of short-circuited rotor bars in a squirrel cage induction motor?

• To increase rotor weight

• To decrease rotor resistance

• To provide a path for induced currents

• To reduce stator to rotor air gap

How does the number of poles in an induction motor affect its speed?

• It has no effect on speed

• It increases the speed

• It decreases the speed

• It makes the speed erratic

What is the significance of slip in an induction motor?

• It determines the rotor weight

• It indicates the efficiency of the motor

• It measures the difference between synchronous and actual rotor speed

• It controls the stator resistance

What happens when slip becomes more than 1?

• It becomes generator

• Motor Stops rotating

• Motor is in braking Mode

• Motor runs above synchronous speed

What would be slip at maximum torque

• R2/X2

• X2/R2

• R2/Z2

• X2/Z2