1) In a 3-phase synchronous motor how do the power output, line current, power factor and efficiency compare against torque applied?
Synchronous motors turn at a speed that is proportional to the frequency of the line current. Power output is a function of applied torque and motor speed. The power factor is the ratio of kilowatts (input) to kilovolt-amperes (output). Torque, thus, is a function of amperes used. Motor efficiency is the ratio of mechanical output to electrical input. In a 3-phase synchronous motor, an increase in applied torque means that more amperes will be used (the power output will increase and the power factor ratio will increase; line current will not change).
2) Compare the synchronous motor power factor to the three phase cage motor and the wound rotor induction motor.
An important advantage of a synchronous motor is that the motor power factor can be controlled by adjusting the excitation of the rotating DC field. This characteristic allows a synchronous motor to have a leading power factor, a lagging power factor, or a unity power factor. In a wound rotor induction motor, the power factor always lags input line current. Three-phase cage motors also tend to have lagging power factors; however, this condition can be altered through the addition of correction capacitors.
3) Comment on the Capacitor Start Induction Run Motor speed regulation.
Capacitor start induction run motors are electric motors that require higher levels of current when starting or when changing speed than such motors require during normal operations. The capacitor starting device regulates current draw to (a) allow continuous operation without (b) creating a power overload. The capacitors activate when higher levels of current are required, and they disconnect when the extra power no longer is required.
4) What is the condition for Maximum efficiency in the Capacitor Start Induction Run Motor?
Generally, maximum...