Induction Motor Construction.
A device that converts electricity into energy is named a motor. All motors can be divided into two main parts.
Namely: 1. Stator and 2.
Rotor.
The motor that has two coils in the stator and rotor and
voltage is induced from the stator to the rotor is called induction motor.
There is no connection between the stator and the rotor of the induction motor,
rather they work in the induction process. In 1817, the great scientist Nikola
Tesla invented the first induction motor.
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Types
Induction motors can be divided into two parts based on
electrical connections.
1. Three-phase induction motor.
2. Single-phase induction motor.
Depending on the structure of the motor, the induction The motor can be divided into two parts.
1. Squirrel Cage induction motor.
2. Wound Rotor or Slip Ring Induction Motor.
Structure
The induction motor consists of the following parts.
Stator
The stator is that the stationary a part of the motor.
The stator has a wire coil called the stator coil and this stator coil provides three-phase power supply. The stator can be further divided into 3 parts.
E.g.
1. Stator frame: This is the outermost part of the
stator. Its main function is to hold the stator core and the stator coil. The
stator frame also protects the motor from external injuries. So it has to be
quite strong and made of steel.
2. Stator core: The main function of the stator core is
to generate directional flux. The three-phase of the stator core is grooved to
twist its coil. The stator core is laminated to eliminate the current loss.
3. Stator coil: The groove in the stator core has
three-phase winding coils, called stator coils. When a three-phase connection
is given to these coils, a rotating magnetic field is created.
Rotor
The rotor is that rotating a part of the motor.
Mechanical load is applied to the rotor through the shaft. The rotor of the
induction motor can be further divided into two parts. E.g.
1. Squirrel Cage Rotor: The rotor of the Squirrel Cage
induction motor is cylindrical in shape and has grooves on it. In the grooves,
it is twisted which is called a rotor coil. These grooves are not parallel but
slightly curved.
This curved groove prevents the magnetic locking of the stator
and rotor. These grooves are attached to a kind of round disc called the
end-ring. The Squirrel Cage rotor is made of aluminum or copper.
2. Wound Rotor or Slip Ring Rotor: This type of rotor has
an equal number of poles in stator and rotor. But the number of grooves and its
coils is less in the rotor than in the stator.
This type of rotor has no direct
connection of three-phase power to the rotor coil. Rather the three-phase the connection is connected to the rotor shaft with a slip ring.
Cooling fan
When the induction motor runs for a long time at the same
time, a lot of heat is generated. A fan is attached to the rotor shaft to
dissipate this heat.
Air gap
0.4 mm from the stator to the rotor depending on the
motor. To 4 mm. The distance is kept. This is called an air gap.
Bearing
Ball bearings are used for attachment of rotor and rotor
shaft.
Terminal box
The place where the three-phase connection of the motor
is given is called the terminal box.