View Full Version : electrical problem

10-18-2005, 08:20 AM
Hi all,
I have an old hypertherm max 40 plasma cutter. It has a difinite purpose contactor that energizes the main circuit when the switch on the torch is closed. The problem is that the contactor chatters, and eats the contacts up. I tried a different contactor but it still chatters. It has a 24v AC coil, is there anything I can do to stop the chatter? Would a choke coil or capacitor in series with the cotactor coil help? Thank in advance.


Jim Koper
J&R Machining

J Tiers
10-18-2005, 08:25 AM
An AC coil contactor should have a copper "shading" piece on the core.... if that is missing, it will buzz and chatter.

Aside from that, a high current in a wire very close to the coil could foul up action ......

10-18-2005, 02:05 PM
Hi Jim,

Check the voltage across the contactor coil when it's energized. If it's below about 22 volts you could have a problem in the wiring or the control transformer. And it might be the wrong coil entirely. If it's only fed with 12 volts it might pull in but chatter (not too likely).

Coils on these contactors are normally replaceable as an assembly, without having to replace the entire contactor.
Leigh W3NLB

[This message has been edited by Leigh (edited 10-18-2005).]