How to Select Starter for Motor

select contactor,OLR, Isolator , Fuse and many more details for select a motor starter

SELECT BEST STARTER FOR MOTOR

Motor starters are available in different ratings and sizes depending on the motor (AC motor) rating and size. These starters safely switch the necessary power to the motor and also prevent the motor from drawing heavy currents.

Need to Connect a Starter to Induction Motor

A starter is needed for an induction motor (three phase type) in order to limit the starting current. In a three phase induction motor, the rotor induced emf is proportional to the slip (it is the relative speed between stator and rotor) of the induction motor. This rotor emf drives the current through the rotor.

When the motor is at standstill condition (at the start), the speed of the motor is zero and hence slip is at maximum. This induces very high emf in the rotor at starting condition and thereby a very high current flows through the rotor.As the rotor needs a high current, winding draws a very high current from the supply. This initial drawing current can be of the order of 5-8 times the full load current of the motor.

This huge current at the starting of a motor can damage the motor winding's and also this current can cause a large voltage drop in the line.

These voltage spikes may affect the other appliances connected to the same line. Therefore, a starter is necessary to limit this starting current to avoid damage to the motor as well as to other adjoining equipment.