Star - delta connection

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i think this may help you
but by the principles we can get them try for it individually so that you can learn it

I have seen in books that Star connection delivers 1/3 of power compared to Delta connection.Thats why we use Star for start and Delta for running of motor.But i want to know whether delta connection draws 1/3 of the current of star connection.

this is because in star the line voltage is 1.732 times phase voltage. so if 400 volts is given phase voltage will be 231V. and line current is equal to phase current. power also depends on the equivalent resistance as converted from star to delta and delta to star. this is also because most of the motor windings are delta connected. hence the delta of starter is connected to the motor.