The Electrical Contractor Network

ECN Electrical Forum
Discussion Forums for Electricians, Inspectors and Related Professionals

Books, Tools and Test Equipment for Electrical and Construction Trades

Register Now!

Register Now!

We want your input!


2017 NEC and Related
2017 NEC
Now Available!

Recent Posts
Parking lot pole light swap....
by ghost307
Today at 06:25 AM
International Wire Colour Codes
by Tjia1981
Yesterday at 12:08 PM
Son of Sparky
by HotLine1
10/20/16 07:43 PM
Speaking of Plugmold ...
by gfretwell
10/17/16 02:37 PM
Broken battery charger? Check for cobwebs!
by gfretwell
10/17/16 02:30 PM
New in the Gallery:
12.5A through 0.75mm˛ flex (just out of curiosity)
Shout Box

Top Posters (30 Days)
gfretwell 13
HotLine1 7
ghost307 7
renosteinke 6
Potseal 4
Who's Online
0 registered (), 288 Guests and 4 Spiders online.
Key: Admin, Global Mod, Mod
Topic Options
Rate This Topic
#29071 - 09/07/03 09:06 PM contactor keeps burning up..
JohnnyB Offline

Registered: 02/25/02
Posts: 33
Loc: 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.

Work Gear for Electricians and the Trades

Work Gear for Electricians and the Trades
Work Gear for Electricians and the Trades
Arc Flash Clothing, Gloves, KneePads, Tool Belts, Pouches, Tool Carriers, etc. etc....

#29072 - 09/08/03 03:09 AM Re: contactor keeps burning up..
Pinemarten Offline

Registered: 08/23/03
Posts: 122
Loc: 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 06:23 AM Re: contactor keeps burning up..
JBD Offline

Registered: 07/12/01
Posts: 599
Loc: WI, USA
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 09:56 AM Re: contactor keeps burning up..
jdevlin Offline

Registered: 08/07/02
Posts: 402
Loc: 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 05:27 AM Re: contactor keeps burning up..
JohnnyB Offline

Registered: 02/25/02
Posts: 33
Loc: 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.


ECN Electrical Forums - sponsored by Electrical Contractor Network - Electrical and Code Related Discussion for Electrical Contractors, Electricians, Inspectors, Instructors, Engineers and other related Professionals