How are the windings of a wound rotor in an ac threephase in

How are the windings of a wound rotor in an a-c three-phase induction motor energized? By applied three-phase current By alternating primary current By direct current from a separate source By induced current from a rotating magnetic field For a transformation of 50,000 volts to 55,000 volts, it is economical to use a three-winding transformer. an autotransformer. a Scott-connected transformer. a two-winding transformer. The purpose of a distribution transformer in a large electric-power system is to decrease the current for industrial use. increase the voltage for convenient transmission. decrease the current for safe application to precise instruments. decrease the voltage for utilization for electric loads.

Solution

(a) the windings of a wound rotor in a-c three phase induction motors are energized from the induced current from the rotating magnetic field .

(b) the 50,000V t0 55,000 volts , it is elctional to use an auto transformer for these because reduction the size and winding reduced for the small step up voltage is effently done by the auto transformer .

(c) the pupose a distribution transformer in a large electric -power sysytem is to decrease the voltage for the utilization for the electric loads.