PP50 cuts off at 50 amps...Now it gets it's own thread.

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04-09-2013, 09:23 AM
sticks

PP50 cuts off at 50 amps...Now it gets it's own thread.

Quote:

Originally Posted by sticks

Ironically I am having the same issue with my PP50, but only when I am at the 50 amp setting after about 10 seconds of cutting.

Air PSI is 75+, good ground, 5/8 mild steel 1/16 to 1/8 standoff. Not tripping the overload, and the problem goes away at 47 amps.

3 water separators/filters, Motorguard air filter/dryer, inlet pressure regulated at 85psi running (pressure drop from 90+ when trigger is pulled).

Not trying to hijack the thread, but it applies.

Quote:

Originally Posted by everlastsupport

It sort of applies to this thread, but would have been better to start a new one as the PP60 and the PP50 use different torches. I run my PP50 about 65PSI and my PP60 I run at 72. Sounds like you have dry air, good flow, good ground. So I would experiment with the air pressure. Make sure consumables are good as well.

Quote:

Originally Posted by sticks

Will do. More air pressure for higher amps, or lower? Example - 20 amps - 65psi and 50 amps 70psi (more amps/more PSI)

Quote:

Originally Posted by performance

Actually, lowering the air pressure isn't the best idea for cutting. It can be done, but I have found that there is a better way and you will get better results... Downsizethe consumables for the amperage is a better way. The air pressure you cited is too much on the input side and on the operating side. You should be at 90 psi NO more on supply while static. Operating you should be no more than 73 or so (officially). You can buy smaller diameter holes for the PowerPlasma torch. The S-25 consumables will fit the S-45 and are designed for low amp cutting at the same air pressure.

Is the arc stuttering or going on and off completely?

Quote:

Originally Posted by sticks

On and off completely.

And like a fool, I bought the 75pc consumable kit which are all the same size tips, #8 if I had to guess. I wish you guys had a variety pack of the 6, 8, and 10s.

I'll adjust the inlet pressure to 90, and verify my operating pressure at the torch is 73ish. When it acts up again, I'll tinker with the air pressure up and down to see if it goes away.

OK, I adjusted my static input pressure to 88ish (as close as I can get to 90 with this regulator without going over). Cutting pressure is 73ish static, and drops to 67 or so while cutting. New tip and electrode. Still cuts out (arc quits) after a few seconds of cutting, and no overload light. I did try running the air up and down a little bit to see if it made a difference. Nope.

I drop it down to 47amps and the problem goes away - No I did not try 49 or 48 amps.

Power source is a Miller Bobcat 250, (10kw generator) plugged into my 240v 2 phase, but wired for 240v single phase on a 50a breaker. I have not hooked up an ampmeter to it yet to see what I am drawing, or verifying that the voltage is still holding at 240vac/60hz. That is going to take a little dismantling of parts to isolate individual legs.

Suggestions?
04-09-2013, 12:54 PM
performance

Do you mean 3 phase? That's not recommended since there phase angle is slightly different than standard. It's likely that has something to do with it and Likely the cut issues not cutting max etc are caused by it as well. Bobcats typically don't put out the same quality power as the Trailblazers. If you don't have your fine adjustment turned all the way up to the very max you are short changing your cutter.

YOur air pressure should be 73"ish" while cutting.
04-09-2013, 02:24 PM
Big Paulie

I had a similar issue with my (other brand) 50amp MOSFET PC. I noticed that air pressure was less of an issue than moisture content. you definitely need dry air, and if running from a smallish compressor, that is usually not the case. Moisture in the air will definiitely chew up (blacken) the eletrode and tip, and caused the cut outs in my case. BTW, instead of just replacing the consumables, I found that they clean up really well by soaking in acid (5% conc of white vinegar) overnight.

Did you visually check the consumables, and also test it on mains power, rather then the generator?
04-10-2013, 10:32 AM
sticks

Quote:

Originally Posted by performance

Do you mean 3 phase? That's not recommended since there phase angle is slightly different than standard. It's likely that has something to do with it and Likely the cut issues not cutting max etc are caused by it as well. Bobcats typically don't put out the same quality power as the Trailblazers. If you don't have your fine adjustment turned all the way up to the very max you are short changing your cutter.

YOur air pressure should be 73"ish" while cutting.

Yes, I meant 3 phase - brain fart.

Not sure what you mean by "Phase angle". Wired Ground, X & Y. Like I said, I need to get things apart to check the sine wave on the Hz and verify amperage draw.

The fine tune is all the way up, and since this is a company truck, I don't have an option to pick a different welder. I was hoping to get one of the new Lincoln Ranger 250's but that went to the other two trucks, and the 305 went to the fabricator. I have one of the last two Millers still running. At least it's not the 225 - that one won't even run my MIG.

During my tinkering with the air pressure during the last check, I'm sure it got up to the 73ish range. Hard to keep cutting and read a dial at the same time.

Quote:

Originally Posted by Big Paulie

I had a similar issue with my (other brand) 50amp MOSFET PC. I noticed that air pressure was less of an issue than moisture content. you definitely need dry air, and if running from a smallish compressor, that is usually not the case. Moisture in the air will definiitely chew up (blacken) the eletrode and tip, and caused the cut outs in my case. BTW, instead of just replacing the consumables, I found that they clean up really well by soaking in acid (5% conc of white vinegar) overnight.

Did you visually check the consumables, and also test it on mains power, rather then the generator?

My air compressor is an IR 40cfm @ 90psi, 2 - 30 gallon tanks in series, 3 water separators (including the one on the PP50) and a motorguard M60 last in line. I have not even seen vapor in the last separator yet. The wet tank catches most of the water, a little in the dry tank, after a full day of working the first separator has a little (teaspoon) and the second has a trace.

The electrodes only have the heat discoloration, and arc burn marks.

I don't have access to building main power. One of these years I'll get my garage extended and wired proper, until then I am stuck with using the welder.
04-10-2013, 04:05 PM
zoama

Quote:

Originally Posted by sticks

Hard to keep cutting and read a dial at the same time.

Put the switch on constant flow to set working pressure, then put it back on timed flow to work.
04-10-2013, 09:35 PM
performance

Google electrical phase angle. They don't have the same as regular power due to their rotor design, especially the 3 phase units. The additional issue is if you have wye or delta (don't know on MIller units), but if you measure from from leg to ground, you may find one leg is actually a hi leg but measures from leg to leg as 220. This unbalanced condition can create issues in some electronics.
04-13-2013, 09:42 AM
sticks

I know when I was initially checking the output of the 240 outlet on the welder, I was getting 120v from each leg to ground. I'd have flagged it for replacement if the legs were reading different (I so want this thing gone).

I Googled Electrical Phase Angle, and could not find anything that I could understand. My education only went so far. If the difference between the two legs is less than one volt to qualify for a different phase angle...it may be there. Maybe today I will get my scopemeter hooked up to it to watch the sine wave for each leg.