A static phase converter will not do a thing for a transformer type 3
phase welder. It might do OK on an old rotary welder. Some one on
sci.engr.joining.welding NG tried a rotary phase converter. Seems to me
it didn't work as well as expected. I suspect that the inductive load
from the welder interacts with the nade up phase from the converter.
(Hmmmmm sounds like a GREAT final exam question for a EE major!)
But many of the transformer welders will run OK on 2 phase at 2/3rds
power. The output from the transformer goes to a massive diode block,
you are just missing one phase. Not as smooth as full 3 phase but
decent. You may have to experiment with which phase is dead since there
will be fans, control circuits, etc that will be running off a single
phase.
Specifics on which make and model you are looking at would be helpful.
Ignoramus15786 wrote:
RoyJ sez:
" But many of the transformer welders will run OK on 2 phase at 2/3rds
power."
Little problem with your arithmetic, today RoyJ ? Your reply is totally
misleading. You should know by now from reading posts on RCM, there is no
such thing as 2 phase (generally) available to the home shop machinist.
Bob Swinney
The output from the transformer goes to a massive diode block,
Sure it's single phase but you can put it into a 2 phases of a 3 phase
machine. And if you reference it to neutral, you indeed have 2 phases.
Robert Swinney wrote:
Gunner pretty well answered the OP's question when he stated:
"Specifics on which make and model you are looking at would be helpful."
In other words the original question was so non-specific as to only be
answerable in non-specific terms. However, this was no deterrent to some
that blurted out "facts" anyway as they hastened to confirm their lack of
knowledge on the subject.
Bob Swinney
wrote:
I have run my Airco Pulse Arc 300 (3ph) on my 5hp rotary converter
with .35 wire. Worked pretty well, but damn it made the electric
meter spin like a dervish. Ive not tried to run it on single phase
as I loaned it to a buddy who does have 3 phase in his shop, but will
be getting it back soon as his shop has my warehouse attached..and the
City is going to turn it into another badly needed abandoned empty lot
at the first of the month.
Gunner
"Considering the events of recent years,
the world has a long way to go to regain
its credibility and reputation with the US."
unknown
Say what? They going to tear it down with nothing going up there?
There's got to be more of a story behind this - the ink isn't even
dry on the Supreme Court eminent domain ruling, and CA is supposed to
have some pretty strict Eminent Domain restrictions over and above
what the Feds just bestowed.
As in, today they wouldn't be able to get away with bulldozing out
"blighted" Chavez Ravine for "housing projects" then conveniently have
the project fall through right after the Brooklyn Dodgers announce
they'd like to move west...
If a municipality already owns the land and building, it isn't in
imminent danger of falling down, and they have no use for it, offer
them a few bucks of month-to-month rent to leave the building
standing.
Even if it's a token rent in exchange for taking care of the place
till they come up with a use for it, it's probably more than they'll
get for a stupid vacant lot - you can find those just about anywhere.
--<< Bruce >>--
--
Bruce L. Bergman, Woodland Hills (Los Angeles) CA - Desktop
Electrician for Westend Electric - CA726700
On Sat, 09 Jul 2005 05:07:07 GMT, Bruce L. Bergman
Ayup. The very large oilfield shop (complete with 8' radial arm drill,
Rockford shaper, 36" x 15' lathes, etc...is owned by one of the local
empire builders.
The land is owned by the railroad. The tracks were removed 10 yrs
ago, and a bike path put in.
Evidently the owner wants to build some housing elsewhere in town, so
the city wants him to remove the building before granting him a permit
to build on the other side of town.
I understand that if the renter can come up with $2,000,000 liability
insurance per year, he has a chance of keeping the building..but he
claims the amount per month will double his rent.
Ive sublet a corner of the machine shop to store machines. The rent is
the odd occasional bit of tooling and bits and pieces that I give him.
Plus I supplied him with loaner machine tools, so there is no cash out
of pocket and is a win win for us both.
He gets tech support, machine tools etc..and I get a decent sized
corner of a 140 foot by 60 foot steel building, with 1000 amps of 3
phase, a 10 Ton overhead crane that runs through the building, etc
etc.
He is a transmission rebuilder and race car builder. Disabled vet
also.
The street that the shop is on, was the main hub of the oilfield
warehouse/supply/services part of town. Since the bottom fell out of
the oil field in the early 80s..most of the buildings have been torn
down, and there is nothing but a half mile of dusty empty lots with a
bike path running through it.
So while its not being done under the eminant domain thing..tis being
done via blackmail. No permits until the 'eyesore" becomes another
dusty empty lot. Its a dying town unfortunately, and the city fathers
think it will come back. One of the old builders here claims they are
going to turn it into a retirement community. Right..they closed the
hospital 5 yrs ago, and the nearest medical services is in
Bakersfield...35 miles away. Lots of folks are going to retire here.
Ayup. A Kmart, an Ace hardware..and a main street filled with empty
storefronts and For Rent signs..that have been up for years.
Gunner, a bit pissed off.
"Considering the events of recent years,
the world has a long way to go to regain
its credibility and reputation with the US."
unknown
You can buy a new manufactured home, on a foundation on a 2 acre lot,
zoned universal, for less than 90k. The average 3 bedroom home, here,
on a city lot is less than $100k, and most run $60k.
We have a federal prison, a state prison and a return to custody
facility within 10 miles of town, but most of the employees of those
places live in Bakersfield, 30 odd miles away, because of the
shopping, entertainment and so forth. Its an easy commute.
I love the area, low crime, good schools, very low taxes (for
California) and while it tends to be in the 100-107 range during the 4
summer months..its a very dry heat as humitity is quite low.
Gunner
"Considering the events of recent years,
the world has a long way to go to regain
its credibility and reputation with the US."
unknown
My experience has been that a transformer machine will work well on a
rotary phase convertor, up to the limit of the convertor's ability to
produce the third phase.
Older machines without solid state output control (Miller migs with the
three big coild with brushes that slide on them) should work well on
single phase, as another poster recommended it'll be important to
isolate the line that feeds the fan, etc.
John
It depends on the 3 phase welder. New Millers for example are possible of
many voltages and phase or legs.
Old versions of 3 phase would likely be best on a rotary I suppose but the
other tuned type might work.
Just use a 220V motor to drive a shaft that couples to a shaft of a 3 phase...
Martin
--
Martin Eastburn
@ home at Lion's Lair with our computer lionslair at consolidated dot net
Don't be an ignoramus - Oh waitaminit, I've gotta remember who I'm
talking to here... ;-P
Go to www.millerwelds.com Go to the 'Service & Support' tab, then
the 'Owners Manual' sub-tab, and enter CP-300 in the model box and the
serial number in that box, and the exact instruction manual for your
welder should pop up in a .pdf file. And you're good to go. ;-)
It wouldn't show me the book for your particular welder because I
don't have the serial number. Obviously, when they made mid-year
upgrades, they reprinted the manuals to cover them. I looked in my
paper catalog, and the current model CP-302 is 3-phase only.
If it's three phase only, that's what the transformers inside need
to see - the inverter style units can adapt, transformers can't unless
they were designed for both 1ph and 3ph. Static converters are out -
they are simply a start capacitor box to get motors going, they won't
supply effective running power to the third leg.
A rotary converter will probably work IF you connect the
manufactured leg only to the welding transformer - two of the legs go
to the control circuits and they'll need to be the two Utility
supplied legs. Call or write Miller for details, I'm sure they've
been through all this thousands of times...
Hell, I'd just order up a new Big-40 or Trailblazer 302 and be done
with it. Just add fuel and go.
--<< Bruce >>--
--
Bruce L. Bergman, Woodland Hills (Los Angeles) CA - Desktop
Electrician for Westend Electric - CA726700
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