Cigweld Transmig 330 Welder Haas-Kamp Conversion (3 phase to single phase)

[bfwa]

Hi everyone, I have been lurking around here for the past few months reading up on the Haas-Kamp welder conversion after having purchased a Cigweld Transmig 330 welder at an auction for the grand ole price of $20. I knew it was 3 phase at the time and did not know if there was any way I could convert it to run off single phase power, but for $20 I thought I would take the chance.

I have read just about every thread I could find a dozen times over trying to understand the process as much as possible, so I could apply it to my welder. I think I've come to the point now where I need to ask a few questions before I jump in and get it done.

So I live in Australia and need the welder to run off 240v single phase power. It is designed to run off 220/380/415V. My model is the remote one - due to the remote wire feeder. Here are the specs:


Inside Electronics
The welder isn't as old as a lot of the other conversions performed and has a few extra basic electronics inside, including the remote wire feeder. From what I can tell, these all run off a single phase and only need to have a jumper set to 220/380/415V. I plan to set it to the 220V jumper.

Circuit Diagram
Below is the original circuit diagram, and a new circuit diagram that I modified based on what I believe needs to be done to run the welder off single phase.
NEW


OLD


So I feel confident with the adjustments I've made to the circuit diagram, however I have no background in any of this, and only weld as a hobby so I really need someone to pull me into line, or confirm for me what I'm planning is correct.

Capacitor Value
I calculated the total value of the capacitors required to be about 80uF. This doesn't seem right. It's nowhere near the value any of the other conversions required. Can someone please check my calculations?

C=(21/3)/2*3.14*60*240
C=7/90432
C=77.4uF (Round up to 80uF)

So would this mean that I need 40uF either side of the centre transformer?

Input requirements
This is the part that confuses me. Once the conversion happens, what will be the input electricity requirements to run the welder without any issue? Obviously 240V, but will the amps required be those shown in the machine specs under 220V? Should I make sure to use to 25A outlet on a 40A circuit breaker?

These may seem like basic questions, but I hope someone can help me if you are able to.

I plan to post the instructions once I can confirm the conversion was successful.

Thank you for your help!
Sam

 

[DaveKamp]

Hi Sam!

Looks like you got the main transformer connections figured out. Don't forget on the control transformer (upper left side of diagram)... set that one to 220v.

You're running 60hz in Australia? I thought 50hz was the standard... if so, plug that into your formula instead.

Total ENERGY requirement for the welder will be the same regardless of wether it's three or single phase... if it pulls 11.4kw on three phase, it'll pull the same on single, just calculate KW demand against your 220v mains to get a current range.

 

[johansen]

The capacitor value you calculated would result in 7 amps flowing through a 77uf capacitor directly connected across the 240 mains.

The actual capacitor value would be more like double or triple that for a few reasons,

one being that the capacitor is in series with the transformer and probably does not have 240vac across the capacitor during operation,
Two being that the inductive reactance of the transformer is a parasitic load, three being you need more than 7 amps to flow through that coil, but that also depends on what you are welding.

Also you only need one capacitor, not two in series. In your example, two 40uf capacitors in series make a 20uf cap which would be too small to do anything

 

[DaveKamp]

The capacitor value you calculated would result in 7 amps flowing through a 77uf capacitor directly connected across the 240 mains.

The actual capacitor value would be more like double or triple that for a few reasons,

one being that the capacitor is in series with the transformer and probably does not have 240vac across the capacitor during operation,
Two being that the inductive reactance of the transformer is a parasitic load, three being you need more than 7 amps to flow through that coil, but that also depends on what you are welding.

Also you only need one capacitor, not two in series. In your example, two 40uf capacitors in series make a 20uf cap which would be too small to do anything

This is not correct. TWO are required to work properly. Since they're not in series, the potential across the capacitors will NOT always be symmetrical, because the center coil is reactive in a substantially more complex system... one side's waveform will be substantially out-of-phase with the other, and that will modulate with loading.

Realize that the center coil, although driven by phase shift, it's current will modulate in sympathy to load, and it's reactance will have a whole lot to do with it.

Empirical testing has regularly yielded between 60 and 120uf for machines in the 200-250v range and 250A class. This isn't a familiar model, but I expect the character of it to fall somewhere in that realm.

To further complicate matters, the machine is not operating in it's original three-phase 120 degree alternation sequence- it's operating in a quadrature, where the two end coils are 180 degrees out of phase, and the center is at some angle between 45 and 130 degrees. Under load, it will naturally be pulled TOWARDS 90 degrees... the capacitors get it in the ballpark, and physics does the rest.