How does a star connection and delta connection work? How
does the star connection save starting current and how does
it change to delta?
Answer Posted / pillay
A typical 3 phase motor has 3 sets of windings. Each set of
windings have 2 terminals namely the start and the end of
the winding.During the start the end of of all 3 windings
is joined together through a contactor known as the star
contactor and the 3 phase power supply is applied across the
start terminals of the 3 windings.This windings are actually
designed for the application of 2 different phase voltages
across them.So during start up lower voltage is applied and
so a lower current is drawn. but after a few seconds the
connections are changed through the change over of
contactors to the full voltage across the windings known as
delta connections. This start and change over is done by
timer controlled contactors.
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