Steve,

Thanks for your reply, I shall investigate and
respond.

R

--- Steve <amptramp@...> wrote:

> Howdy Roughbert,
>
> It would be a pity to throw it away. Indeed, it
> would be a crime
> against the great 'Gods of Weldness'.
>
> Ok, I have to admit to a good degree of ignorance on
> mains powered
> welders, as I don't have mains power here, or a
> mains welder.
>
> Could I safely assume that your welder is little
> more than a heavy
> transformer in an oil filled container?
>
> If so, perhaps you may try these tests:
>
> Measure the resistance of the output windings.
> This will be very low, so low that it will appear as
> zero ohms.
>
> Measure the resistance of the mains input windings.
> This will be higher, but still quite low.
>
> Heat the old girl up, until she goes lame.
>
> Repeat the ohmic measurements.
>
> This ought to tell us a lot more about the fault.
>
>
> Another test, if the ohmic tests on the secondary
> side are impossibly
> low:
>
> Unplug the welder from the mains,
>
> Connect a 12V, 50W headlamp in series with a 12V
> battery to the
> welder's secondary side,
> The lamp should slowly light up.
>
> Keep a mental image of its final brightness.
>
> Disconnect the lamp and battery circuit.
>
> Heat the old girl up until she starts limping again,
>
> Repeat the lamp and battery test,
>
> Is the lamp's brilliance level the same?
>
> If so, this suggest a possible problem with a part
> called the 'sliding
> choke'.
> This part is used in some welders as a current
> controller.
> Perhaps this part moves in response to temperature?
>
> I honestly don't know just how these are used, but
> they certainly can
> cause the problem you are seeing.
>
>
> Do you have any pics of the welder?
> Can it be taken apart?
>
>
> In the meantime, perhaps you could use it to build
> an AmpTramp :) .
>
> Now there's a good project for the old girl ;) .
>
>
>
> Best wishes,
>
> Steve.
>
>
>
>
>
> --- In Amptramp@yahoogroups.com, "roughbert"
> <roughbert@y...> wrote:
> > Hello Group.
> > My recently-acquired but ancient oil-filled BOC
> welder works a treat
> > when cold, but after a couple of hours work it
> becomes dreadfully
> > feeble (now what does that remind me of?). I
> assumed that somewhere
> > some resistance is creeping in - or out. Is there
> anything practical
> > which one can do about this, or should it be
> consigned to the heavy
> > scrap pile?
> > R
>
>
>