Explain the principles and characteristics of induction motors.
Explain how torque is produced.
Calculate slip.
Solve a problem involving slip, given number of poles, frequency and motor
speed.
Sketch and label the torque/speed characteristic for a single cage induction
motor, indicating starting torque, pull-out torque and synchronous speed.
Explain how the torque/speed characteristic is affected if the rotor
resistance is increased.
Draw a power flow chart for a three phase induction motor.
Calculate useful shaft output power and efficiency at full load.
Explain how speed control is achieved in an induction motor
Explain Calculate efficiency for induction motor.
Explain the effect of reduced voltage on standard squirrel cage motor with respect to each of the
following.
Burn out.
Starting current.
Starting torque.
Speed.
Question
With reference to a 3speed a.c. cage motor driven cargo winch
Sketch a circuit diagram for a pole change motor
D State the problem that would occur if large induction motor such as bow thruster unit were
started direct on line.
Outline 6 proactive design methods that may be employed to eliminate problem that occur during
starting of large induction motor.
With reference to the condition monitoring, of electrical machinery:
