I would agree the duty cycle on transformer based machines mainly applies to the core temperature of the transformer, capacitors are in use on various things 24 hours a day all year roundExceeding its duty cycle shouldn't have caused it to go bang. We've all done this and if you start pushing it, it should just cut out on over temp and want half hour to cool down.
Doing this on every session will shorten the poor things life mind and it's time to get something bigger if that's the case but a short blast into the top end shouldn't hurt it. Sounds like yours has just gone pop. It happens but might be worth investigating why it's gone pop before fixing it to go pop again.
The thermal cut out isn't there for the duty cycle though, is there to prevent permanent damage when people ignore the duty cycle and will cut out well after the duty cycle time has passedSounds like the cap just blew, as there is a thermal cut out in place
to stop overheating and a light to alert you there is a fault.
Thanks for that info, I have a parweld XTM 305 so will keep an eye out in case I over do it.The thermal cut out isn't there for the duty cycle though, is there to prevent permanent damage when people ignore the duty cycle and will cut out well after the duty cycle time has passed
It should state the duty cycle on the machine at various settings for example full power weld 10 mins rest it for 10 mins, this is just an example so take no notice of those timesThanks for that info, I have a parweld XTM 305 so will keep an eye out in case I over do it.
Think it would be more sensible to cut the unit out at a certain temperature than put on a light first,
that in most cases will not even be noticed. Not much logic in that set up.
I had it cranked up to max, which I'd never done before as my old workshop wasn't wired for it. Of the three caps, 1 looks OK, one blew the electrolyte and the other one is bulging. So I think it is worth replacing all of them and keeping the good one as a spare.
Richard: What kind of things should I be checking for before replacing the caps? I've had a good look around. Nothing else looks damaged/burnt/leaking, but I guess that is not a great way of checking.
Fazerruss: in terms of identifying ripple current for my replacement caps, all I can find out about these caps is that they are 80v, 105°C, 4700μF. What should I be looking for?
Thanks, Geedle.
I'm sorry mate I wish I could answer your Q but electronics are not my forte. Generally though from previous experience when something goes bang it's often a result of something else that's failed. It may not be the case in your situation but if you can have it checked out its worth while as you don't wanna be fitting new gubbins only for the initial problem to have another stab at them again.Richard: What kind of things should I be checking for before replacing the caps?
You mean check you don't have AC coming from the rectifier diodesAs Richard said, a part can be effected and even damaged because of another part
not working properly.
From the OP 's description he says he may have stretched the duty cycle on the machine,
this alone can cause the caps to blow, but other things can also cause them to blow.
Some one once told me their caps blew and were replaced and did the exact same again
within a 20 minutes.
The problem in that case was the rectifier Diodes had went bad, and allowed AC to reach
the Caps, they don't like AC an will of course be destroyed.
So check that you have ac coming from the diodes, it may even be obvious from looking
at the diodes to see some damage, but best way is to check them with a meter.
I am not well up on this stuff, but my understanding is that no AC should be getting to the circuit the caps are inYou mean check you don't have AC coming from the rectifier diodes
In your post I replied to you wrote, so check you have ac coming from the diodesI am not well up on this stuff, but my understanding is that no AC should be getting to the circuit the caps are in
as they are DC, if they get AC won't that destroy them.
Does this make sense.
I started a new thread on here to enquire as to where the caps fit into the mig welding machine so I wouldn't be hijacking this one.
http://www.mig-welding.co.uk/forum/threads/capacitors-in-a-mig-welder.69688/#post-928996