Core loss is neglected in single-phase induction motor. The excitation branch consists of only ________.

Equivalent circuit of single-phase induction motor

The equivalent circuit of a single-phase induction motor can be divided into two main components:

Main (Excitation) Circuit: Represents the magnetizing and core losses of the motor.

• Exciting reactance (X_M): This represents the magnetizing reactance, accounting for the magnetizing current that creates the rotating magnetic field.
• Core Loss Resistance (Rc): It represents the losses due to eddy currents and hysteresis in the core.

Rotor Circuit: Represents the rotor resistance and leakage reactance.

A simplified equivalent circuit can be drawn in terms of the "Double-Revolving Field Theory", which states that a single-phase supply creates two rotating magnetic fields: one rotating in the forward direction and the other in the reverse direction. Each of these magnetic fields induces its own current in the rotor.

Explanation

In a single-phase induction motor, when the core loss is neglected, the excitation branch consists of only exciting reactance.

The exciting reactance represents the inductive component of the motor that accounts for the magnetizing current required to produce the magnetic field. When core losses (which are associated with eddy currents and hysteresis in the magnetic material) are ignored, only the reactance associated with the magnetic field remains in the excitation branch.