Christopher Tidy wrote:
RoyJ wrote:

OK, ya got me. I've never seen a fully oil submerged welder(only a
similar sized pole transformer rated 4130/120/120 at 5 kva). Contacts
submerged in oil does not sound like a good thing.

As for diodes, Original equipment diodes may cost an arm, leg, and
first born. Suitable replacement diodes can be had for US$10 or less.
Unlikely to be an exact fit in the diode block though. Could be just
one, 2 in a center tapped setup (both will be blown if you have no
voltage), or a full wave bridge (probably blew a couple )

Oil does get contaminated if not fully sealed. If the oil is visibly
murky I'd probably want to change it. If not, why bother for home use?


Thanks to everyone for the advice. It sounds like the best idea is to
cautiously open the case in a clean area, at some point when I don't
need the welder for a while, and have some extra oil ready to make up
for spillages. I should get the chance to do it in the next month or so.

I've also heard that oil helps to quench arcs at contacts (you got
oil-filled circuit breakers, right?) but I wouldn't have thought this
would be a problem with a welding transformer as you don't adjust the
current while you're welding. I think the main purpose of the oil is for
cooling, but it also keeps the inside dry and corrosion free. The set is
similar to a pole transformer in many ways, and is also rated at 5 kVA.
Fortunately the top opens, so I can get inside without draining the oil.
Would you like me to post some pictures if I disassemble it?

I, too, thought of making a diode bridge to connect to the outside of
the set, but it seems like a bit of a messy solution. It would be much
neater to fix the battery charger. I'm also rather curious to see inside
the set myself.

Will keep you informed of progress.

Best wishes,

Chris


Any chance this is a PCB oil? Nobody has mentioned it, I'm curious..

John