Answer Posted / dhanush d
In a 3 phase induction motor,the magnitude of the induced emf depends on the value of the slip.
At start a large emf is induced in the rotor circuit
Stator consequently draws a large start starting current which is 5 to 8 times the load value.
This may damage the motor as well as the components in line with it
Therefore,a Starter not only limits the starting current but also provides protection against low voltage and high load condition.
At the beginning the 6 ends of the three phase windings are brought out and connected as Star connection this reduces the voltage in each phase by 1 /√3 times the value it would,if it was in delta connection.
And tge starting current reduces to 1/3 of its value.
but the torque also reduces.
As this method is cheap, its used in mixers abd drills.
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