Construction of Induction Motor

Construction of Induction Motor

In this section we see the construction of Induction motor. Generally the people does not know what is inside of the motor. Which part are used in the motor, what is the used of this part. Following fig.shows the cross sectional view of Induction motor:

        Fig. 1 Shows the Cross-Sectional View of Induction Motor

Fig.2 Shows details part of Induction Motor

Motor Parts & their uses:

1.     Stator : As its name indicates stator is a stationary part of induction motor. A stator winding is placed in the stator of induction motor and the three phase supply is given to it.

2.     Rotor : The rotor is a rotating part of induction motor. The rotor is connected to the mechanical load through the shaft. The rotor of the three phase induction motor are further classified as

A. Squirrel cage rotor

B. Slip ring rotor or wound rotor or phase wound rotor.

3.     Shaft : Shaft is fix inside the rotor & also bearings, cooling fan are fix on the shaft. It is used to couple motor with other machine. 

4.     Motor Body or Frame :  The motor body is generally made of aluminum for small motor & for large motor it is made from casting. The main used of motor body or frame to give support to endsheilds & to protect the stator winding.

5.     Endsheild : Two Endsheils are used in motor. One is from driving side & other is from non- driving side. These are fix on the frame of motor. The main purpose of this is to protect winding & give support to rotor.

6.     Bearing : Two bearings are used in motor. One from DE side & other NDE side . These are fix on motor shaft. The main purpose of bearing is to reduce the friction.

7.     V-Ringer slider or V Seal : It is place after bearing & it is fix in endhield. It is made of high quality rubber. It used is to protect bearing from dust.

8.     Fan : Fan is mounted on shaft at NDE side of motor. It is made by plastic or casting. The use of fan is for cooling purpose.

9.     Fan Cover or Fan Cowl : It is mounted NDE side of the motor & it fix on motor endsheild or body. The purpose of this is to protect person from rotating fan & also the flow of air to be directional.

10.   Terminal Plate : It is mounted on motor body. The leads of motor winding coming from stator is connected through terminal plate (Y or Delta). Terminal plate is made by insulating material.

11.   Terminal Box : The Terminal Box Type AC induction motor family allows the power cable to be fixed with the cable clamp and seal connector to provide greater security for a variety of uses. No terminal crimping is needed as the lead wires are directly inserted into the terminal block. The terminal box is made from Aluminum or casting.

12.   Eye Bolt : It is used to lifting the motor.

13.   Grease Nipple : This is generally used more than 37 Kw motor. The use of grease nipple is to feed grease inside the of bearing.

14.    Name Plate : Name plate is fix on every motor. It gives the motor information. E.g. Kw & HP Ratings , Rated Voltage , Full load current, Frequency ,Efficiency, Power Factor, Rated Speed, Bearing use, Ambient Temp.,Motor Frame Size, Insulation & their temperature class, Efficiency class , Manufacturing years & also motor unique machine number or identification number.