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What is lamination in induction motor?
Lamination is necessary since a voltage is induced along the axial length of the steel as well as in the stator conductors. The laminations are insulated from each other usually by a varnish layer. This breaks up the conducting path in the steel and limits the losses (known as eddy current losses) in the steel.
Does current flow in the rotor of an induction motor?
This is referred to as “induced” current flow. In other words, in an induction motor the current flow in the rotor is not caused by any direct connection of the conductors to a voltage source, but rather the influence of the rotor conductors cutting across the lines of flux produced by the stator magnetic fields.
What is rotor lamination?
The Importance of Lamination The rotor consists of a steel lamination and resembles a cylindrical core with evenly-spaced slots for its three-phase windings. The lamination process consistently reduces the loss of iron. Since the lamination is made of steel, the assembly will also reduce Eddy current loss.
What are the types of rotor of induction motor?
There are two types of induction motor rotors:
- Squirrel-cage rotor or simply cage rotor.
- Phase wound or wound rotors. The motors that use this type of rotor are known as Slip-ring rotors.
Why lamination is used in motor?
Stator laminations reduce eddy current by insulating the core. Thin silicon steel plates are stacked on top of one another around the center, preventing eddy current flow. With the eddy current reduced, the stator core can maintain constant power, keeping your motor running.
Which type of rotor is used in 30 induction motor?
Squirrel-cage rotor or simply cage rotor. Phase wound or wound rotors. The motors that use this type of rotor are known as Slip-ring rotors.
How is current induced by an induction rotor?
Rotor as the name suggests it is a rotating part of an electrical machine, in which current is induced by transformer action from rotating magnetic field. Induction motor rotor is of two types:
What are the parts of an induction motor?
Parts of an induction motor An induction motor has 2 main parts; the Stator and Rotor (Fig:1). The Stator is the stationary part and the rotor is the rotating part. The stator is basically a 3 coil winding and three phase AC power input is given to it.
How does an induction motor current analysis work?
INDUCTION MOTOR CURRENT ANALYSIS (CURRENT SPECTRUM TEST) – This test is performed while the motor is under 50 – 100% load. The rotor induces currents back in the stator windings. These currents appear as side bands around the supply line frequency (60 HZ) peak, and are a function of the motors number of poles and slip frequency.
Why are rotor bars skewed in an induction motor?
One of the purposes of skewing the rotor bars is to increase the value of rotor resistance so that starting torque can be improved. We know that resistance is proportional to length hence by skewing the rotor bars length of bars is increased hence resistance increases so does the torque.