a salient pole 60 Hz synchronous motor with a squirrel cage winding on the rotor which is used for starting purposes.
(a) What is the frequency of the current in the squirrel cage rotor conductors immediately after the motor is energized? (The motor was initially at standstill.)
(b) What is the frequency of the current in the squirrel cage rotor conductors after the field is energized
and the machine is operating at steady state?
(c) Assume the machine is initially at steady state operating at rated voltage and unloaded, when a three-phase short circuit occurs on the terminals of the machine. If you could monitor the current in the squirrel cage conductors, what would you expect to see? Explain.
(d) The equal area criteria to determine if a synchronous machine will remain "stable" after a disturbance is essentially an application of the principle of conservation of energy. Very briefly describe how this process can be used to describe the response of the machine to a particular transient.