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Construction of induction Motor( with Diagram)

By Cayla | Published on Sep 16,2015

1. Stator:

(1)Stator core: 0.5mm thick silicon overlying formed, part of the magnetic circuit. The stator core is one part of the motor magnetic circuit, mounted inside the base. In order to reduce the iron loss of the stator iron core, stator core is made of a 0.5mm thick laminated silicon, on both sides of the silicon is coated with insulating paint. The following figure shows the stator slots, wherein (a) is an opening slot, for large and medium-sized capacity high-voltage induction motor ; (b) is a semi-open slot, for medium induction motor 500V or less; (c) is half-closed slot for small low-voltage induction motors.

(2) Stator windings: magnet wire formed, part of circuit. The stator winding of high pressure and medium-capacity induction motor is often used Y connection, only three lead, as (a) below. For medium and small capacity low voltage induction motor, usually six wires of three-phase stator windings are lead out to, if necessary, can be connected to a Y-shaped or △ shape, as shown in (b) below. The stator winding is wounded with insulating copper (or aluminum) wire , embedded in the stator slots.

(3)Base: Cast iron or steel plate welded. Mainly use to fix and support the stator core. If it’s the bearing motor, except for supporting the rotor portion of the motor. Therefore, base should have sufficient mechanical strength and rigidity. For medium and small induction motor, usually use cast iron base. For large motors, commonly use steel welding frame base, the entire frame and pedestal bearings are fixed on the same floor.

2. Rotor

(1) Shaft: supporting the rotor

(2)Rotor core: 0.5mm silicon overlying formed, part of the magnetic circuit. It is part of the motor magnetic circuit, which is formed by 0.5mm thick silicon layers. Core is fixed to the shaft or the rotor frame, the entire outer rotor would be cylindrical.

(3)Rotor winding: It is divided into cage type and winding type.

1)Cage rotor: squirrel-cage winding is a winding shorted themselves. Putting a conductor in each slot, connected together with end rings at both ends to form a short-circuit winding. If the rotor core is removed, the remaining windings shaped like a squirrel cage, as shown in (a), the so called squirrel cage rotor. Conducting bar is made of copper, also made of aluminum.

2)Wound rotor: Wound rotor grooves are embedded with three-phase windings that composed of insulated wires, are generally connected into Y-shape. Three leads are separately connected to three slip rings , led out by a set of brush arrangement, as shown in picture. This allows the external resistor in series to the rotor winding circuit to improve the starting performance of the motor or adjust the motor speed.

3. Air gap

Part of the magnetic circuit, compared with the same capacity DC motor, the air gap of induction motor is much smaller. In the medium and small induction motor, the air gap is generally about 0.2 ~ 1.5mm.


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