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SINGLE PHASE INDUCTION MOTOR

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TYPES OF SINGLE PHASE INDUCTION MOTOR:
Shaded Pole(Very Small Motors)
Split-Phase
a) Capacitor Start Capacitor Run Motor ----- Fan Motor
b) Capacitor Start Inductor Run Motor ----- Fractional H.P. motor for Pump sets.

2(b) Capacitor Start Induction Motor:


MOTOR MAINTENANCE:
MECHANICAL:
Greasing the bearings.
Alignment with the pump, blower, etc.
Vibrator check.
Motor body temperature.

ELECTRICAL:
Measure the insulators resistance of the motor winding.(To be at least above 10 mega ohms)
Terminal block and termination of windings
Double earthing of motor body.

HARMONICS:

*) The AC voltage or current in a non linear electrical load will have odd and even harmonics. The odd harmonics especially 3rd and 5th , will result in unwanted losses called harmonic losses.
*) The 3rd harmonics will have its frequency 3 times its fundamental frequency. Suppose the fundamental frequency is 50 cycles per second, its 3rd harmonic will have 150 cycles per second.
*) In order to reduce the harmonic losses, it is required to have filter circuits comprising of inductance and capacitance(LC filters) in the non linear loads such as UPS, VFD.
*) It is better that the total harmonic distortion of voltage is maintained 10% or less and the THD(Total Harmonic Distortion) of current 5% or less.

THREE PHASE INDUCTOR MOTOR:
The motor converts electrical energy into mechanical energy. This motor works as electrical induction. This motor has a rotor and stator. The stator has a 3 phase winding. The rotor can be of cage type or slip ring type.

The cage rotor has solid aluminum or copper bars inserted in the rotor slots where as the slip ring rotor has a 3 phase winding terminated on to 3 slip rings.