Induction motors are widely used in everyday life both in industry and in households. Induction motors are commonly used 3-phase induction motor and 1-phase induction motor. 3-phase induction motor operated at 3-phase power system and is widely used in various industrial fields, while the 1-phase induction motor operated at 1-phase power systems are widely used, especially in use for household appliances such as fans, refrigerators , water pumps, washing machines and so forth because the 1-phase induction motor has a low output power.
The construction of the induction motor
Induction motor basically has 3 important parts as follows.
1. Stator: It is part of silent and have a coil that can induce an electromagnetic field to the coil rotornya.2. Gap: This is the air gap: The transfer of energy from startor to the rotor.3. Rotor: It is the part that moves due to the magnetic induction from the stator coil is induced in the rotor coils.
Induction motor stator construction basically consists of a portion-portion as follows.
1. Houses stator (stator frame) of cast iron.2. Stator core of soft iron or silicon steel.3. Alur, together with the core material, where this path is the place put windings (the stator coil).4. Winding (coil) of copper stator.
Order induction motor stator well designed with four objectives namely:
1. Covering the core and coil.2. Protects engine parts that move from direct contact with humans and from scratches caused by interference or disturbance object open air (weather outside).3. Distribute torque to the engine support equipment and therefore the stator is designed to withstand the forces of revolution and turmoil.4. Useful as a means of air ventilation so that the cooling housing more effectively.
Based on the shape rotor construction, the induction motor can be divided into two types as shown in Figure bellow
Squirrel cage rotor and wound rotor
1. Induction motor with rotor cage (squirrel cage).2. Induction motor with rotor windings (wound rotor)
a) Stator Frame b) Rotor winding c) Rotor Cage
construction of the induction motor
Construction rotor induction motor consists of a portion-portion as follows.
1. Rotor core, the material of soft iron or silicon steel with the stator core.2. The flow, the material of soft iron or steel with silicon core. Flow is the place put windings (coils) rotor.3. Rotor windings, the material of copper.4. Shaft or axle.
Between stator and rotor air gap there is a space between the stator and rotor. At this air gap flux of induction through the bypass stator coils so that the rotor causes the rotor to spin. Air gap between stator and rotor are arranged so that the obtained results the optimum motor work. When the air gap between stator and rotor is too large will result in low efficiency of induction motor, otherwise if the distance between the gap is too small / narrow will lead to mechanical difficulties on the machine. Form a simple description of placement stator and rotor induction motor is shown in Figure bellow.
Overview simple induction motor with one coil rotor and one coil rotor stator
A cross (x) on the stator coil or rotor in Figure above shows the current through the coil into the paper (this paper) while the dot (.) Indicates that the direction of flow out of the paper.
Stator windings are connected to a voltage source will produce a magnetic field which rotates with synchronous speed (ns =, 120f/2p). Rotate the stator field will be cut in the rotor conductors, so that the induced currents, and in accordance with the Law Lentz, the rotor will also rotate following the rotating stator field. Differences relative rotation between the stator and rotor is called slip. The growing burden, will increase the motor coupling will therefore also increase the induced current in the rotor, so that the slip between the stator rotating field and rotor rotation would be greater. So. When the motor load increases, the rotor rotation tends to decrease.
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