
OPERATING CHARACTERISTICS OF
INDUCTION MOTORS
This chapter is concerned with how the induction motor
behaves when connected to a constant frequency supply.
This remains by far the most widely used and important
mode of operation, the motor running directly connected to
a constant-voltage mains supply. Three-phase motors are the
most important, so they are dealt with first.
METHODS OF STARTING CAGE MOTORS
We have seen that the starting current in a cage motor
supplied at rated voltage is perhaps five or six times rated
current, at a low power-factor. Where the impedance of the
supply system is low, the volt-drop caused by even such a
large curren ...