plasma cutter powered by phase converter?

I run my 1250 off real 3 phase without a hitch. However I can see where it would be sensitive to the incoming power (think VFD and how sensitive they are to input) and not work off a rotary phase converter. It's probably sensing the dropping voltage of the generated phase and kicking off.

You might try rotating the phase wires around one position. If it uses a single- phase transformer, this might bring the bulk of the load over to the line phase.

The input power goes from the cord to the power switch to the input of a three phase bridge on those units. Straight to DC. It's a big switching supply basically.

At 230-240V 1ph it draws 44A per leg, at 230-240V 3ph it draws 26A per leg. I don't see a good reason to try to run it on "fake" 3ph if you don't have "real" 3ph. It's not like a big welder pulling 100A per leg, it's a kitchen range.

Pete C.

Is this the one that was posted on Craigslist in the Seattle area? I almost jumped on that myself...let us know how you did when you get it working well.

On a similar note....I need a little info from the real world rather than literature on the higher amperage models of these hypertherms.

Eventually, I need to be able to CNC cut up to 3/4" (usually only 5/8") T304 stainless including some piercing operations. I hated to underbuy so passed on the one mentioned above due to hypertherm saying that it needed an edge start for those thicknesses.

Any recommendations on models/amperage that'll do the thick stainless, leave a cut that can be profile milled later without much trouble, and won't have me buying more machine than I need?

For a while, I'd only be using it for hand cutting thinner gauges so it'd be waaaaay overkill..however, would rather buy the right one to start than buy twice.

Thanks,

Koz

I tried swapping the leads around a little, only tried 2 of the 6 possibilities but some of those are redundant.

GWE

Grant, I don't see why there is an advantage to running off of a three phase converter (if you could). All you're doing is transferring the single phase current that the plasma cutter would have drawn to the single phase input of the phase converter--plus a little more current to dissipate in the converter.

Go for the single phase. By the way, nice machine. I almost bought one, but dropped back to the 650 in the end.

Steve

Grant Erw> Just picked up a used Hypertherm Powermax 1000 plasma cutter. Seems

Suggest calling Hypertherm and talking to an app engineer to select the best unit. Hypertherm is pretty much the best so you'll want one of their units anyway.

Pete C.

Yup, it's that one. I made him an offer and he bit. I was a little surprised. It came with 34 extra electrodes and 29 extra nozzles and one extra guard and an entire extra gun minus lead, torn down for parts, plus original manual and even the receipt from when he bought it @ Praxair about 2 years ago.

Eric Snow wrote me today:

".. a Thermal Dynamics Cutmaster 101. It claims to be able to cut 3/4" steel at 10 Inches per minute. This claim is true. After testing both the Hypertherm and the Thermal Dynamics the deciding factor was the start method and CNC interface option. The TD uses some kind of capacitive start instead of high frequency like the Hyper. This is helpful when connecting the machine to a computer for CNC use. TD also sells a circuit board that plugs into the machine which allows the computer to directly control the amperage, start, and etc. And the torch cable is a quick- disconnect so that the machine can be connected to a machine torch for CNC use or the hand torch can be connected for manual use. My plan is to eventually have a CNC plasma cutter set up."

If Hypertherm says the 1000 won't pierce 3/4" stainless, it probably won't. Conversely, if they said it would, it *might* .. but it's unreal to think of reverse specsmanship and them admitting it won't do something it will.

GWE

You would need a very mighty phase converter to run a 60 a 3 phase load... What is your phase converter like?

i

No, it isn't 60 amps of input power at 220 volts. On 220-3 power, the machine draws 26 amps of input power. My phase converter supplies a genuine 30 amps at

220 volts - the idler is 7.5hp. Obviously the generated leg isn't clean enough, because when I connected it today to single phase 220, the machine worked OK, haven't yet had time to thoroughly check it out.

Grant Erwin

Hum - How about getting a 3 phase transformer and use the core to provide the surge currents. I have a 220 rotary and boost it upward with three transformers and 3 more bucking transformers to get the level I wanted.

One large core or three transformers.

Now for a buddy that has one to loan out - or a junk yard...

Martin

Martin H. Eastburn @ home at Lions' Lair with our computer lionslair at consolidated dot net NRA LOH & Endowment Member NRA Second Amendment Task Force Charter Founder IHMSA and NRA Metallic Silhouette maker & member

Wayne Cook wrote:

It is better to over size a plasma machine - the specs are rated for MILD steel.

I have been able to cut 1/2" 400 BHN armor plate with my 600, but with the new head that works with the next size up machine. So the 60 amp nozzle on a 40 amp machine seems to cut much better than a 40. I suspect it is an impedance issue - but not sure.

Cutting SS - I do 304L and it cuts - but you need to cut with more current than is normally thought and at a faster movement. More current means hotter steel and the further it will blow away before cooling. Less dross dripping on the bottom.

Martin

Martin H. Eastburn @ home at Lions' Lair with our computer lionslair at consolidated dot net NRA LOH & Endowment Member NRA Second Amendment Task Force Charter Founder IHMSA and NRA Metallic Silhouette maker & member

Koz wrote:

I have a CNC plasma machine - and we connect to all Hypertherm without issue. A great number of machines function - a special cable is within.

Just having an interface board - sounds great - if you are doing your own - even better. Check with the CNC table people on the requirements - save your money.

Some machines require the interface - depends on the vendor.

Martin

Martin H. Eastburn @ home at Lions' Lair with our computer lionslair at consolidated dot net NRA LOH & Endowment Member NRA Second Amendment Task Force Charter Founder IHMSA and NRA Metallic Silhouette maker & member

Grant Erw>

Most of that info is incorrect. The Hypertherm Powermax 1000 does not use HF to start the arc / plasma stream, it uses a blowback system. It also comes standard with a CNC interface port (CPC type connector on the back).

As for piercing 3/4" stainless, read the manual. I believe the issue with piercing such thick material is not the piercing capability, but rather nozzle and shield life. A CNC that provides "wiggle pierce" or better still a tilt axis to pierce at an angle as you would by hand will greatly reduce the problem.

Pete C.

I'd say that the Powermax 1250 would be the right machine for you. It's what I have and I'm extremely happy with it. The new torch they have on the 1000 and above is the best torch I've ever used. It will cut thin stock clean and quick and without changing anything go right over and cut 1" stock just as clean (though not as quick). For CNC use I wouldn't go any smaller especially if you're going to want to do

3/4". It's rated for 7/8" and though I've never tried on that thickness I do know that it handles 1" pretty well if slowly.

I know it uses blowback on the normal start but it seems like it has HF on when in gouge mode. I've not verified this but that's just the way it acts to me.

Agreed. Piercing 3/4" thick is tough to do without messing something up. My experience is that if you'll do a traveling pierce it works better. When I was doing a lot of stainless work on a pattern torch setup I just turned it on and then hit the trigger so that it pierced while cutting. That worked much better than trying to stay in on place. Staying in one place does several things including making a mound of material on top which can get stuck to the nozzle shorting it to the work.

Greetings Koz, I bought the Thermal Dynamics Cutmaster 101 because it is slated for CNC use eventually. It uses a capacitive start method instead of high frequency. It is harder to shield computers from the high frequency than 60 Hz. When the trigger is pulled the air runs for a bit and then there is a kind of snap in the torch and the arc is established. Two other features on the Cutmaster are the quick disconnect torch and the option to plug in a circuit board that allows direct control of the plasma cutter by the CNC control. Hypertherm may offer these options. The one that I test drove at Central Welding, which they said was comparable to the Thermal Dynamics 101, did not. Both machines cut equally well when using the hand held torch. The quick disconnect feature allows the hand torch to be used even after the machine is connected to the CNC control. Eric

Pete-I can only go by the machines that Central Welding gave me to test. The Hypertherm one used high frequency, at least it acted like the high frequency on my TIG welder, and I was told that it did. The TD machine did not. Of course things change in a year. ERS