Capacitor duty contactors

PFC-Capacitor Duty Contactors Power Factor Correction Systems

Capacitor switching contactors are fitted with early make contacts and damping resistors, to reduce the value of make current <70 x Ie

Really, now, a simple search would have given you the answer.

WHen switching on a capacitor, there is a high ampacity and high frequency charge current (oscillation is between capacitor and the inductance of the upstream network. You can consider that closing on a discharged capacitor is the same , in the first microseconds, as closing on a short circuit.

So you need to have specific design :

• either temporary insertion of resistor
• or permanent series inductance
• or synchronized contactor which closes at the 0 voltage
• or static switch ...

In any case, the money you put in the device is to compare to the life expectancy of the device itself, and of the capacitor (high inrush currents increase the ageing of capacitors).

As always in this electrical business, cheap is not the most economical, and things are not as easy as they may appear in first sight .. This is why we have specialists ;-))