Hello and good morning to all members. A retired electrician told me
that to prolong the life span on the contact point of the contactor,
you can add one capacitor between the two contact point. By theory it
sound acceptable, but i had not try it out,because this is to control a
ac 230 volts 1600 watts heater. Does any member can advise in this
issuse. Thanks.
Regards
A capacitive arc snubber connected across a contact can reduce the
flash each time the contact opens. By diverting the load current to
the capacitor for a brief moment, it allows the contact to get enough
air between the points that and arc is not drawn between them.
However, that same capacitor can dump a big current into those points
when the contacts close, causing them to pit and possibly weld
together. For this reason, such snubbers also include a resistor in
series with the capacitor.
This sort of thing works best with inductive loads, like motors, where
the inductance causes the current to decrease more slowly than the
voltage does. Resistive loads, like heaters do not produce the extra
voltage at the moment contacts in series with them open, so a snubber
may not help much. You may just need a bigger contactor.
But if you want to try it you will need a 1 microfarad capacitor rated
for use with 240 volts AC or more (or 1000 volts DC) and a 47 ohm, 2
watt resistor. Connect them in series and across the contact points.
Here is a data sheet for an example of a capacitor type rated for
across the line, AC operation (class X), available from Digikey:
http://www.panasonic.com/industrial/components/pdf/abd0000ce30.pdf
