what time should we set to come on star contacter in
stardelta starter?and for what reason we hav to set such
time delay range?

Answer Posted / srinivas

In star delta starter first star contactor will be in action after some delay time delta contactor will come in to picture and no need of time delay for star contactor.

At the time of starting motor ohmic resistance is zero and hence the back EMF zero. So it will takes more current, it may cause winding damage. So we have to reduce the starting currents. it is possible by connecting the motor terminals as star at the starting. Time delay range depends on what type of load used in motor and rating of motor. Normally the time delay range will set to reach above 70% of the motor load.

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