Lit match smell coming from the control box

Greg7683

Member
Join Date
Jun 2018
Location
Plainfield IN
Posts
355
Yup it tends to smell like sulfur smell in one or two of our control boxes been doing it for years but was never able to figure out where it was coming from. Any Ideas as to what parts can be emitting the smell. It has servo amps PLC modals in it as well as other stuff in the box.
 
Some components on circuit boards give off different smells when burning. You would have to tear down each one and look for burnt components.


You could remove items one by one, power them up on the bench under a load, and see if the smell is coming from that one. Since it is more than one panel I would look for components that are common to them.
 
It may not even be anything burning. A lot of times electronics give off certain smells when they warm up, and it really varies. *MOST* electronics that generate a nice bit of heat have an odor if you get close.
 
Metal Oxide Varistor. A common use is as a surge supressor for AC voltage.

We used to use them on induction heaters, and when they failed it was usually in spectacular fashion. Typically you'd find a big skidmark on the back panel where they were bolted down and a loose wire with the remnants of the connector attached to it, and shrapnel in the bottom of the cabinet.
 
It may not even be anything burning. A lot of times electronics give off certain smells when they warm up, and it really varies. *MOST* electronics that generate a nice bit of heat have an odor if you get close.

My laptop has been smelling for the past few months and I was worried at first but it's been running fine other than that. If the panel has been smelling for two years it's probably fine. You can try to isolate the device it's coming from by powering everything down/turning all the breakers off etc then slowly powering devices on, one by one (turning circuit breakers on, one by one).
 
Any chance that you're near a sewer or drain?

Years ago I was in a plant that was getting water in one of there panels from a leak in the roof. The fix was to punch a hole in the bottom of the cab. and run a hose to a drain. Whomever did this really didn't want the hose coming out of the drain so he pushed it down passed the trap, thus letting the sewer gas up into the control panel.
 
Any chance that you're near a sewer or drain?

Years ago I was in a plant that was getting water in one of there panels from a leak in the roof. The fix was to punch a hole in the bottom of the cab. and run a hose to a drain. Whomever did this really didn't want the hose coming out of the drain so he pushed it down passed the trap, thus letting the sewer gas up into the control panel.

Nope no drains anywhere near that area.
 
If there is a UPS in the panel with a lead-acid battery, that could be the battery venting hydrogen-sulfide gas. You should not have a lead-acid battery in a panel that is not ventilated, bad things can happen.

If not, a selenium rectifier would have had to have been in a 1960's vintage component, like an old linear power supply or something. When you get that smell, it meant the rectifier was failing, to where the forward voltage would be increasing, typically resulting in other parts getting fried. So if it's been going on for a while and nothing has died, that scenario is unlikely. A selenium rectifier always looked like a stack of plates, like fins on a radiator.
images
 
Last edited:

Similar Topics

hey all, I am struggling with a problem here and out of ideas on how else to achieve the desired result. I have a monitor inside a machine with...
Replies
0
Views
107
Hello everyone. I have an PLC L35 (fmw 16) with address 192.168.1.1 and too many connected ethernet devices (3 hmi, a lot of ethernet port, asi...
Replies
11
Views
683
i have been trying to connect to omron cj1m via peripheral port(USB to Serial), but there isn't any sign to show that it has connected, so am...
Replies
0
Views
291
Basic question: I don't understand why Network 4 is split over two lines. I want it to appear like for Network 3, i.e. all on one line. Does...
Replies
1
Views
739
This unit was removed from one project where it had perfomed nicely. Wired into simulator and we have no signs of life no LED,s lit power...
Replies
2
Views
917
Back
Top Bottom