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#29071 - 09/08/03 12:06 AM contactor keeps burning up..  
JohnnyB  Offline
Joined: Feb 2002
Posts: 33
Chicago IL USA
I replaced this ASCO contactor two years ago because it was melted. The coil burnt and the contacts burnt. Two years later its burnt again. Last time I found nothing, amps OK, no sign of shorts. The only thing was that last time some sign guys were in there before me and I though maybe they let the smoke out, this time they were not, but I did find the out door dissconnect boxes and switches rusted away. I'm thinking that the water running off the sign is getting right into the boxes and shorting out the contactor? The coil is getting power form one of the same lines, maybe short circit amps killing the coil too? I dont see anything hooked up to this contactor that would draw anything close to what the contacts are rated for. I'm trying to avoid putting in another 600$ ASCO just to burn it up again.

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#29072 - 09/08/03 06:09 AM Re: contactor keeps burning up..  
Pinemarten  Offline
Joined: Aug 2003
Posts: 123
Edmonton, AB, Canada
Just an idea:
If the armature is sticking or catching on something then it would have the double effect of not closing the contacts all the way so they burn out, and burning out the coil because the air gap isn't closing.

[This message has been edited by Pinemarten (edited 09-08-2003).]

#29073 - 09/08/03 09:23 AM Re: contactor keeps burning up..  
JBD  Offline
Joined: Jul 2001
Posts: 599
It doesn't take much rust, on the magnet pole faces, to cause the problem Pinemarten mentioned. If you try to clean the magnet pieces, remember they are machined surfaces and any scratches will just make things worse.

#29074 - 09/08/03 12:56 PM Re: contactor keeps burning up..  
jdevlin  Offline
Joined: Aug 2002
Posts: 402
welland ontario canada
What does the contactor control. I saw a similar problem after a fire alarm test. They ACs shut down everytime you pull the alarm. They came in on the weekend and tested every pull station. The ACs would shut down everytime and then restart when they reset the system for the next pull station test. When we realized what happend they now shut off the ACs after the first test verifies the AC shut down properly.

#29075 - 09/09/03 08:27 AM Re: contactor keeps burning up..  
JohnnyB  Offline
Joined: Feb 2002
Posts: 33
Chicago IL USA
This is a lighting control, HID lights, outside neon sign lights, inside florecent lightings and EMs. I wounder if a low voltage event could cause this too. I am HVAC guy for comercial maintenance and I had a building loose a leg of power once when I was on the roof doing PM. half the units that tried to start burnt a compressor and when I pulled the cover to one the contactors were trying to pull in and they melted just like this ASCO.

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