Power factor correction of motor 1

[fornhamspark]

can anybody please advise me on power factor correction of a star/delta started motor.

my question is that should the capacitor be switched in with the main contactor or the delta contactor, and from what size of Kvar is it advisable to use a contactor.


Cheers All

 

[Skogsgurra]

Switch the capacitors in with the delta contactor.

There is an advantage with the Y/D starter when it comes to compensation; the motor doesn't stay connected when you switch off. Or rather, the "other end" opens so there is no risk of overexcitation of the motor when you deenergize it. That often happens when you switch off a wye or delta connected motor with the capacitors in-circuit and they are a bit on the high side.

The star time is so short that you needn't bother about compensation then - the pf is also beyond compensation during start.