USAGE OF AC INDUCTION MOTOR


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                      USAGE OF AC INDUCTION MOTOR

AC induction motor is a user-friendly motor it is cheap and low maintenance it could directly connect to the AC source it is mainly used in powered home appliances and in industrial motion control systems it has simple and rugged design there are many types of AC induction motors and each of them has its own applications

Small Ac motors are mostly commutator machine the motor will be prevented from having a shunt connected field by the transformer effect between the field and armature
The starter will apply the power source to the winding small motor will take six times load for 5 or 6 seconds large motor takes 4-5 times to load current for fifteen seconds
The AC induction motor has a fixed portion called stator and a rotor which spins inside

During the starting time, the power factor of the current is really low it will increase according to the motor speed

POWER FACTOR IMPROVEMENT IN AC INDUCTION MOTOR

Inductive coils are connected to the supply and the power factor is in the range of 0.7 to 0.9 and it is really poor and it shows the power loss in supply to the motor is really high in order to improve the power factor a bank of capacitor is added in parallel with the motor the capacitor resistance must be the same as the inductive resistance and it will improve the power factor

SPEED CONTROL OF AC MOTORS

It can be done by the thyristor to control the current and voltage it can be done in another way by converting AC to DC and the DC could be used to power an inverter to give the variable frequency AC supply

EQUATION
A magnetic field created in the stator rotates at a synchronous speed Ns
Ns = 120 × f ̸ p
Ns = synchronous speed of stator magnetic field in RPM
P = number of poles in the stator
F = supply frequency in hertz

APPLICATIONS OF THREE PHASE INDUCTION MOTOR

• Lifts
• Cranes
• Hoists
• Large capacity of exhaust fans
• lathe machine
• Oil extracting mills
• Used in textiles