why the motor running in delta connection ? it can be in star?

Answer Posted / maged

Simple 3 phase motors can be connected in either STAR or
DELTA.
In star the maximum power is reduced but the starting
current is lower than for Delta
In Delta the motor gives maximum power but the starting
current is often too high and the overload trips out.
To overcome this a star/delta starter is fitted
All 6 wires from the motor windings are connected to the
starter and the starter functions are as follows :-

When start button is pressed the motor is automatically
connected in star and the start current is acceptable. At
the same time a timer is initiated and after a
predetermined time the starter automatically changes from
star connection to delta. The motor now runs in Delta until
switched off.

This is a fully automatic starter, many years ago manual
changeover star/delta starters were more common.

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