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CNC Viking
04-17-2009, 08:41 AM
I have an old skool TIG welder (1990) that have some massive coils inside. It is only a 1-phase 230-440V transformer. The primary coil is fed by L1 and L2 (marked F and F in the shematics below) in the 380V setting. Can this be softstarted with resistor(s)? If yes, should I use 1 resistor on L1 only or 1 resistor each on both L1 and L2? What resistor specs do I use?

TIG Welder's inside
http://forumbilder.se/images/0a7200922100Pf545.jpg

General description of the TIG welder
http://forumbilder.se/images/5d7200922357Pc28e.jpg

TIG welders electric shematics
http://forumbilder.se/images/727200922526Pa89a.jpg

/Peter

Edit: I put the correct and tags for the picture links and they do not show directly in the post. Why?

H.O
04-17-2009, 01:10 PM
Hi Peter,
One resistor is enough in this case. As with your VMC I'd use a 47ohm/100W wirewound and then a large enough relay/contactor to bypass it a second or so after initial turn-on.

/Henrik.

CNC Viking
04-17-2009, 06:24 PM
Thanks for the info,

Guess what, the TIG welder was only supplied with a 3-wire power cable (No N-wire).
However, I will soon get a 4-wire cable from my VMC that will be up-graded with a 5-wire cable.

And now I can order same soft-start stuff as for my VMC.

MrWild
04-17-2009, 06:28 PM
NOOOOOOOOOO You have a three phase welder. It will NOT work with house current.

CNC Viking
04-18-2009, 05:17 AM
Hi MrWild,

Yes it is a 1-phase welder indeed, please check the general description and shematics that I link to above in post 1. I can choose to set it for 230V and use L1 and N but then it needs a whopping 50 A power supply, or I can use L1 and L2 which is 2 of the 3 400V-phases that all houses in Sweden have had for ages. In my house I have access to 35A 3-phase 400V.Then of course there is the PE wire, hence the 3-wire power cable it is supplied with.

mc-motorsports
04-18-2009, 05:56 AM
NOOOOOOOOOO You have a three phase welder. It will NOT work with house current.

Things are a little diffrent in Europe. We run 110/220 residential, they run 220/440 I believe.

H.O
04-18-2009, 07:46 AM
Correct but it's actually it is 230/400V. 230V between each phase and neutral, 400V between phases.

All households have 4 wires coming in from the transformerstation near by - 3 phases and a combined neutral/protective earth (PEN). The PEN is then split into a protective earth (ground if you will) and a neutral at the main disconnect panel.

Donkey Hotey
04-19-2009, 12:09 AM
Edit: I put the correct and tags for the picture links and they do not show directly in the post. Why?
It looks like image code is turned off for this particular forum. It used to be that way for the Haas mill forum as well. I'll post a note over in the suggestion forum.

Geof
04-19-2009, 12:24 AM
Correct but it's actually it is 230/400V. 230V between each phase and neutral, 400V between phases. .....

Holy something (starting with s)

In North America the standard residential supply is 240/120 single phase; center neutral with line 1 and line 2, 120 above neutral and 240 apart. I have been zapped by the 240 when I made a mistake; I would hate to be zapped by 400. I suppose that would be something that could only happen once.

CNC Viking
04-19-2009, 05:31 AM
It looks like image code is turned off for this particular forum. It used to be that way for the Haas mill forum as well. I'll post a note over in the suggestion forum.

Thanks Greg,
I see now that the IMG code is off. Kind of you to ask them to turn it on. That will make this forum a little nicer.


Geof,
Yes, you always have to be focused when working with electrics. But IMO I think we have a great system. The higher voltage means less amps and thinner cables. You must have 10's of transformers in every block over there, I guess.:D