Using an old three phase DC welder from single phase?
Ignoramus3512
have three phase input (and has a three phase transformer and three
phase rectifier).
If I use it from just one phase (hook up two terminals to one line
input and the third to another line input), would it be able to make
satisfactory welds? I understand the electrics of this a little bit,
and instead of relatively smooth rectified three phase AC with only 5%
360 Hz ripple, it would be much less smooth rectified single phase AC.
My question is, how good would that be for actual welding, like with
7018 or some such rod.
i
Karl Townsend
"Ignoramus3512" <ignora...@NOSPAM.3512.invalid> wrote in message
news:E6mdndRt5odkn1PW...@giganews.com...
i got no help, but i have about the same question. We picked up an old
monster miller wire feed with a jib crane and spool gun. I haven't wanted to
hook it to three phase cause i don't like to weld in the nice shop area. But
at least i didn't have to pay as much for mine as you did. <VBG>
Karl
sparky
wrote:
You might have to make some control circuit changes and replace the
fan motor if it is 3 phase. Otherwise it should work just the same as
any single phase welder.
RogerN
"Ignoramus3512" <ignora...@NOSPAM.3512.invalid> wrote in message
news:E6mdndRt5odkn1PW...@giganews.com...
It's totally useless, I'll double your money and give you $1.98 for it if
you deliver!
:-)
RogerN
Jon Elson
use 3-phase, unless an inverter-type machine. All the old AC/DC welders
were single phase.
Assuming an all-electric welder, no SCRs and phase control stuff, it
probably would work OK. They usually have such a huge inductor in there
for arc stability that the rectifier ripple won't be very big. I'm a
little unclear how these things did current control, though. The old
buzz-boxes used a variable core plug in a transformer with a lot of
intentional leakage inductance. If the thing has electronic current
control using phase control of SCRs, it is VERY unlikely it will work.
Obviously, you will lose a lot of the current rating on single phase
power. I have heard of people running them very well on a rotary phase
converter, though. If that doesn't appeal to you, I'd strongly urge you
to find an AC/DC machine that is known to run on single phase. I have a
Lincoln square-wave TIG 300, and it is a fantastic machine. I'll never
do stick again, due to the fumes. I LOVE TIG!
Jon
Gunner Asch
LOL....
suddenly that .99 cents is posing some problems?
I believe that you may..may be able to run a jumper to L3 from L1 or
L2..but I can say for sure..and will let one of the smart guys answer
the question.
Gunner
"First Law of Leftist Debate
The more you present a leftist with factual evidence
that is counter to his preconceived world view and the
more difficult it becomes for him to refute it without
losing face the chance of him calling you a racist, bigot,
homophobe approaches infinity.
This is despite the thread you are in having not mentioned
race or sexual preference in any way that is relevant to
the subject." Grey Ghost
Ignoramus3512
> It's totally useless, I'll double your money and give you $1.98 for it if
> you deliver!
>
How about, I give it to you for free (with the high frequency
attachment and cables) in exchange for a on-site CNC consultation. Let
me know soon because if I do not hear from you, I want to get rid of
it quickly. I am in Lisle, IL.
i
Ignoramus3512
> It depends a bit on the welder. First, it has to be a DC only welder to
> use 3-phase, unless an inverter-type machine. All the old AC/DC welders
> were single phase.
It is a big OLD (key word old) transformer welder. I doubt it has any
electronics.
> Assuming an all-electric welder, no SCRs and phase control stuff, it
> probably would work OK. They usually have such a huge inductor in there
> for arc stability that the rectifier ripple won't be very big. I'm a
> little unclear how these things did current control, though. The old
> buzz-boxes used a variable core plug in a transformer with a lot of
> intentional leakage inductance. If the thing has electronic current
> control using phase control of SCRs, it is VERY unlikely it will work.
>
> Obviously, you will lose a lot of the current rating on single phase
> power. I have heard of people running them very well on a rotary phase
> converter, though. If that doesn't appeal to you, I'd strongly urge you
> to find an AC/DC machine that is known to run on single phase. I have a
> Lincoln square-wave TIG 300, and it is a fantastic machine. I'll never
> do stick again, due to the fumes. I LOVE TIG!
I agree.
i
Ignoramus3512
> On Tue, 20 Apr 2010 14:39:37 -0500, Ignoramus3512
><ignora...@NOSPAM.3512.invalid> wrote:
>
>>Let's say I have a big old three phase DC welder that was supposed to
>>have three phase input (and has a three phase transformer and three
>>phase rectifier).
>>
>>If I use it from just one phase (hook up two terminals to one line
>>input and the third to another line input), would it be able to make
>>satisfactory welds? I understand the electrics of this a little bit,
>>and instead of relatively smooth rectified three phase AC with only 5%
>>360 Hz ripple, it would be much less smooth rectified single phase AC.
>>
>>My question is, how good would that be for actual welding, like with
>>7018 or some such rod.
>>
>>i
>
>
> LOL....
>
> suddenly that .99 cents is posing some problems?
>
> I believe that you may..may be able to run a jumper to L3 from L1 or
> L2..but I can say for sure..and will let one of the smart guys answer
> the question.
Well, given that it cost 99 cents, it will be a great experiment. I
will try when I have time.
i
Gunner Asch
wrote:
Which is not true with my Airco PhaseArc350, 300 amp mig welder,
unfortunately.
RogerN
"Ignoramus3512" <ignora...@NOSPAM.3512.invalid> wrote in message
I've got plenty of welders but haven't welded anything in years. But I'd be
glad to help you get your CNC running but through email or newsgroup posts.
Do you have anything to go off of as far as manuals, wiring diagrams, a
napkin with some marks on it? Have you connected power? Does it do
anything? Or how about a picture of the wires coming out of the motor and
the wires going to the amplifiers?
For my Lathe conversion, the motors and amplifiers worked, and the encoders
worked, so I had to connect 5 wires from each encoder to my breakout board
(Common, +5V, A, B, Z). That plus some configuration gets you numbers on
the screen, turn the motors by hand and the numbers change. Change the
counts per unit in the configuration file until you read inches or MM,
whatever you set it for. If the encoder counts backward, number decreases
in the direction it should increase, swap A and B or change it in your
configuration.
Ok, after I got my encoders working on the screen and found out they had
12,700 counts per inch, it was just a matter of connecting my control signal
(2 wires) to my servo amplifiers, the amplifier to motor connection was
already there. I set up a switch to turn the power to the amplifiers on and
off. I put in some values for proportional gain, turned on the amplifiers
and the thing started to work. I adjusted PID gains and feedforward values
to get it working better, the EMC pages have info on adjusting the gains,
there is even a scope that you use on the screen that plots what you want to
look at, in my case it was positioning and following error.
With your math background I don't think you would have much difficulty, you
just need to understand the signals and you can figure out what's missing
from there.
RogerN
Ignoramus10488
machine.
Regarding the welder on single phase question: I just spoke to some
great guy from Craigslist. He want to buy it and he told me that to
run it on single phase, you just need to wire some capacitors to the
third leg. This is kind of an interesting thought.
i
Ernie Leimkuhler
Ignoramus3512 <ignora...@NOSPAM.3512.invalid> wrote:
Iggy I have used those machines for years.
They have several names in the Miller system, 330 AB/P, or Miller
Goldstar, also sold through Airco is orange paint.
Maybe I shouldn't burst your bubble here, but I really hate those
machines.
You have make sure to clean out the spark gap and reset the points in
the high frequency generator.
The high frequency capacitors tend to die so be prepared to replace
those.
In these old TIG machines, Miller's capacitors seem to have a shorter
life span than Lincoln's.
The 5 we had at South Seattle CC eventually started blowing their foot
pedal fuses all the time.
The fuse is an old fashioned screw in type on the side of the front
panel.
Those fuses are getting harder to find.
We eventually found some screw-in type circuit breakers.
These things are just very old, and even in not heavily use, they have
very old insulation on all the transformer coils.
It is not uncommon for the main coil or reactance coil to blow.
Also check inside the machine to see if it has selenium rectifiers.
They look like a stack of big square cards on a long rod.
If a selenium rectifier blows it will produce a cloud of hydrogen
Selenide gas, which is incredibly bad smelling as well as highly toxic.
At the very worst you got about $600 in copper scrap for $1.