Ignoramus11916 wrote:
On Wed, 07 Sep 2005 11:06:15 -0400, JohnM wrote:

Ignoramus25850 wrote:

Someone offers me a hobart mega-arc 300 with 200' of cable, tig torch,
ground clamp etc. Supposedly can be used for tig welding.

No HF starting.

Question, is that a good deal at $500.

It is a 3 phase machine, which does not bother me terribly too
much. If it demands more power than my 10 HP RPC can produce, I will
add another, second idler motor. These motors cost nothing, relatively
speaking, and can be kept in some unused corner. I would spin up the
first idler and only then start the second, and the load after that. I
have 60A in my garage, easily upgradeable to 75A.

Any thoughts?

i


That should be a pretty good machine, but he's asking a lot of money for
it. If the HF is the old fashioned sort, a cleaning of the spark gap or
replacement of the transformer should be all that's required, I think
any ordinary furnace lighting transformer would work fine.


No, it is supposed to be the "new sort", with more electronics and
lighter. Also comes with 200 feet of welding cable and tig gun and
stinger.


Offer him $200, see what happens.

A 10 hp convertor should power this machine well.


My calculation, based on 300 amps at 40V, gives me energy consumption
at least 12 kW. That's a little bit too much for a 10 HP RPC. Am I
mistaken?

I doubt that I will need 300A very often though, although I have no
idea.

thanks John...

i


The last statement is the question; how much are you going to ask from
the machine? Try it out, it'll either suit you or it won't, no big deal
either way.. I'm guessing you'll find it's more than adequate.

HF *should* be easy to repair, regardless of the age of the machine, but
there's sure no guarantees. Go over and ask on sci.eng.welding, I think
there's some guys there who don't hang out here, one of them may have
dealt with that very machine.

John