On Wed, 07 Sep 2005 17:57:45 GMT, 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.

Probably a good machine but parts are almost none existent for these
old Hobart welders. If it has square wave AC capability then it would
probably make a pretty decent TIG welder. If not then aluminum
capability is going to be ok but not as good as the newer welders.


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?

No you're not mistaken. Mine takes 80 amps single phase to run full
out (though I've only got it on a 60 amp breaker).

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

Not likely.

Wayne Cook
Shamrock, TX
http://members.dslextreme.com/users/waynecook/index.htm