I have a Hobart CyberTig 200 DC-S welder. It is a 3 phase 200 A rated
SCR fired, transformer based TIG welder.

I have a PCTI's 3 phase firing circuit that is made to control any SCR
fired, transformer based, 6 SCR power supply, by specifying current
and voltage with potentiometers.

It is shown he

http://www.pcti.com/3phfiring.htm

It appears to be very straightforward to wire it (I have a
manual). What I would like to use it for is to convert it to a both CC
as well as CV operation so that I could use it as a TIG/Stick or MIG
welder.

The nice thing is that, it seems, it can be wired without disturbing
too much in the welder. All I need to do is unplug the current
Programmer controller, add some piggy back terminals, and connect this
circuit in. I would start with a simple control for CC and then expand
a little bit by making it control valves, HF and switch from CC to
CV. (CC is set by specifying max voltage as OCV and controlling
current with a pot, whereas CV is set by specifying max current and
controlling max voltage with a pot).

My question for now is this: Is this CyberTig actually a 300 A, 60%
duty cycle welder, controlled to run at no more than 200 amps, or is
it really a 200A max welder. It is specified to have 100% duty cycle
at 200A.

i

Most of the boxes are rated for the max heat dissaption possible from
the core.

Ignoramus19116 wrote:
I have a Hobart CyberTig 200 DC-S welder. It is a 3 phase 200 A rated
SCR fired, transformer based TIG welder.

I have a PCTI's 3 phase firing circuit that is made to control any SCR
fired, transformer based, 6 SCR power supply, by specifying current
and voltage with potentiometers.

It is shown he

http://www.pcti.com/3phfiring.htm

It appears to be very straightforward to wire it (I have a
manual). What I would like to use it for is to convert it to a both CC
as well as CV operation so that I could use it as a TIG/Stick or MIG
welder.

The nice thing is that, it seems, it can be wired without disturbing
too much in the welder. All I need to do is unplug the current
Programmer controller, add some piggy back terminals, and connect this
circuit in. I would start with a simple control for CC and then expand
a little bit by making it control valves, HF and switch from CC to
CV. (CC is set by specifying max voltage as OCV and controlling
current with a pot, whereas CV is set by specifying max current and
controlling max voltage with a pot).

My question for now is this: Is this CyberTig actually a 300 A, 60%
duty cycle welder, controlled to run at no more than 200 amps, or is
it really a 200A max welder. It is specified to have 100% duty cycle
at 200A.

i

On Wed, 19 Apr 2006 00:09:37 GMT, RoyJ wrote:
Most of the boxes are rated for the max heat dissaption possible from
the core.

You are right, but, I suspect, this is a special case.

Also, since it is rated at 200 amps 100% duty cycle, it would be a
great leap from it to 300 amps, 60% duty cycle.

I saw some vague allusions in the manual to higher capacity. (the dig
setting at 200A increases amperage, and also the Programmer manual
mentions simple changes to switch to 300A)

i

Ignoramus19116 wrote:
I have a Hobart CyberTig 200 DC-S welder. It is a 3 phase 200 A rated
SCR fired, transformer based TIG welder.

I have a PCTI's 3 phase firing circuit that is made to control any SCR
fired, transformer based, 6 SCR power supply, by specifying current
and voltage with potentiometers.

It is shown he

http://www.pcti.com/3phfiring.htm

It appears to be very straightforward to wire it (I have a
manual). What I would like to use it for is to convert it to a both CC
as well as CV operation so that I could use it as a TIG/Stick or MIG
welder.

The nice thing is that, it seems, it can be wired without disturbing
too much in the welder. All I need to do is unplug the current
Programmer controller, add some piggy back terminals, and connect this
circuit in. I would start with a simple control for CC and then expand
a little bit by making it control valves, HF and switch from CC to
CV. (CC is set by specifying max voltage as OCV and controlling
current with a pot, whereas CV is set by specifying max current and
controlling max voltage with a pot).

My question for now is this: Is this CyberTig actually a 300 A, 60%
duty cycle welder, controlled to run at no more than 200 amps, or is
it really a 200A max welder. It is specified to have 100% duty cycle
at 200A.

i

I have spent the last couple of days troubleshooting a pair of Canox
tig welders. These machines are rebranded Miller welders and are old
enough to be free of electronics. One of the welders is rated 300 amps
and the other at 400 amps. Even though the sheet metal on the 400 amp
one is a bit more modern inside they are extremely similar. From the
owners manual that I downloaded from Miller you can figure out what
parts are different by looking at the parts list which is very comlete.
From the manual it is clear that the 200 amp model is almost exactly
the same as the 400 amp model. What I don't understand is why Miller
would sell such similarly built machines with such a range of capacity.
Today I got the 300 amp model working, tomorrow I'll start on the
second one.

stan

As for my Hobart CyberTig, what I think is that it is basically their
300 amp 60% model, with a different Programmer (controller) that only
allows 200A.

Good chance that the inernals are the same. But putting a current
limiter (governor) on it reduces the number of warranty returns and
other bad press. Yours is a 3 phase machine which means industrial duty
only. A lot of the 'operators' (these aren't really welders) will run
the machines hot for long periods of time. Especially those on piece rates.

On Wed, 19 Apr 2006 15:17:02 GMT, RoyJ wrote:

As for my Hobart CyberTig, what I think is that it is basically their
300 amp 60% model, with a different Programmer (controller) that only
allows 200A.

Good chance that the inernals are the same. But putting a current
limiter (governor) on it reduces the number of warranty returns and
other bad press. Yours is a 3 phase machine which means industrial duty
only. A lot of the 'operators' (these aren't really welders) will run
the machines hot for long periods of time. Especially those on piece rates.

Thanks Roy. I think that your analysis is right. I will try to find
out more.

i