Operational Principle Inverted or rotor-fed induction motor
When the rotor winding and stator winding are connected to distinct three-phase supplies with the same frequency (say, 50 Hz), the stator generates a spinning magnetic field, which is then transmitted to the rotor. Rotor will revolve in the same direction as the rotor’s magnetic field.
By transformer action, the rotor magnetic field induces an EMF and current in the stator, causing a magnetic field formed in the stator to behave in opposition to the stator magnetic field. Rotor frequency will be associated with slip in the stator. As two magnetic fields try to oppose each other, the rotor’s rotation slows or stops.
The motion of the rotor is entirely dependent on the phase difference between the stator and rotor applied voltages. The rotor’s speed is determined by the difference in frequency between the rotor and stator, denoted as (fs-fr). Some harmonics will be generated in both the stator and the rotor because the rotor functions as a frequency converter in magnitude.
(fs-fr) or (fs + fr)
The inverted or rotor fed induction motor’s stator has three short-circuited phase windings. The rotor also features three-phase windings that are coupled in a star arrangement. Each coil finishes at the slip ring. The slip rings are positioned to the rotor shaft, and the brushes ride on them. The slip rings connect the three-phase power supply to the motor.
The graphic depicts the block diagram of a typical inverted or rotor-fed induction motor.
Inverted or Rotor Fed Induction Motor
Induction motors consist of a stationary stator and a spinning rotor. In normal operation, the stator draws power from the alternating current mains. In an inverted or rotor-fed induction motor, the rotor contains three-phase windings from which a three-phase AC supply is supplied. The winding of this rotor must be in a star arrangement. This inverted or rotor-fed induction motor is used experimentally because it exhibits mechanical revolving qualities in both the stator and the rotor.
In a traditional three-phase induction motor, the supply mains provide a balanced three-phase feed to the motor stator. In contrast, an inverted or rotor-fed induction motor contains three-phase windings and is powered by a three-phase balanced supply from the alternating current mains. The rotor windings of the inverted induction motor must be in a star configuration.
Table of Content
- Inverted or Rotor-fed induction Motor
- Construction
- Operational Principle
- Advantages
- Disadvantages
- Applications