[ToC]

 

STAR-DELTA STARTERS

Coyne Electrical Trouble Shooting Manual, Educational Book Publishing Division, Coyne Electrical Radio School, 1948

This job is used to demonstrate the difference between the ends of each phase on a 3 phase winding, and to show that this difference must be taken into account when the phases are connected together.

Proper connection of the windings on any 3 phase motor, generator, or transformer, must be preceded by identification of the phase ends as starts and finishes, just as the proper connection of a battery to others must be preceded by the finding of the positive and negative terminals.

The simplest method of finding the starts and finishes of the phases in a three phase motor is given below. Follow each step carefully. With the windings connected star, a test will show unequal voltage per phase with an incorrect connection. This explains why the motor hums when the phases are improperly arranged.