10hp RPC runs Airco Mig just hunky dory

Ive got a mint Airco PhaseArc 350 mig welder, which is a 3phase machine so havent been able to run it here at the homestead. When I had the warehouse, I was able to use it down there because there was

3ph. Hating to have machines taking up space that I cant use, I decided to see if it would run off my current 5hp RPC. To make a long story short..It wouldnt. (PRC is Rotary Phase Converter btw), which is basicly nothing more than a 3ph motor spun up to speed in some fashion, and then it will run on single phase 220, and it generates the 3rd leg all by itself, allowing you to hook up 3 phase industrial type equipment to it.

I had a brand new Marathon Elect 10hp 3450rpm motor kicking around so I decided to breadboard it up into a bigger RPC and see if it would run the Airco. Getting it up to speed was the problem, as I couldnt spin it fast enough with a rope wrapped around the shaft, so micky moused up a 1/2hp 110vt 3450 moter, pulley and flat belt to spin the big motors shaft directly, before applying single phase power to it. Which worked just fine.

God that big 10hp motor is loud when it runs....I could hear it 200 yrs away, Of course..bolting it to a pair of I beams, then sitting loose on the top of my welding bench turned the bench into a sounding board....aaaaack!!

Anyways...plugging the Airco mig into the impromptu RPC. I found the motor itself was idaling at about 18 amps on each input leg, and the output legs generate 240, 2399, and 233 volts across the output legs, with the manufactured leg provideing 233 volts. With the Airco turned on, simply ideling, current went up to about 22 amps per leg, and here is the funny part...at 25 volts, burning .45 DualSheild, with 150 amps indicated on the welder, total current draw only went up to 28 amps, raising the voltage to its top 35 volts...far far into the OH FUCK spray transfer mode, only raised the total amps to 35 with an indicated 250 amps of weld current. Chuckle..burning that hot was like using a spray gun, the weld looked like it was composed of nothing but tiny ball bearings, and had absolutly no simularity to a weld at all. It was a sponge.

So, I showed that I can run a decent sized 3 phase industrial type machine on single phase power, which in this case was the spare electric dryer outlet, fused at 40 amps, run into a 50' 6/3 extension cord out to the welding area (which is on its own 60 amp circuit), by making up a simply rpc.

I think however..Ill start looking for a 1725 rpm 10hp motor , as the noise and the air from the fan itself is like a hurricane, at 3450 rpm

Gunner

"Pax Americana is a philosophy. Hardly an empire. Making sure other people play nice and dont kill each other (and us) off in job lots is hardly empire building, particularly when you give them self determination under "play nice" rules.

Think of it as having your older brother knock the shit out of you for torturing the cat." Gunner

Reply to
Gunner Asch
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Sounds great. I am also very open minded towards buying a 3 phase welder. I am sure that I could get it up to serious amps.

Some random thoughts.

I am very surprised that a "new" motor would be so loud. Something is not right. I have two phase converters, 10 and 7.5 HP, and both are relatively quiet, except when in the second one I forget to turn off the starting caps (of which it requires a lot).

You can spin up that 10 HP idler from your 5 HP idler. Start the 5 HP idler first, get it up to speed, and then plug in the 10 HP idler by means of a contactor or appropriate mechanical disconnect. Then apply load. You would have a 15 HP idler capacity RPC.

i
Reply to
Ignoramus26409

(snip)

Cool!

Does it seem to run any smoother than a comparably-sized single-phase machine -- as perhaps your Dan MIG?

Reply to
Don Foreman

I bet if you worked on it you could get that idler to run a lot quieter. Make the feet *right* so nothing is twisted, nothing is loose, everything's just solid and no teeny warps. Then rubber-mount the whole bidness. I bet that would knock off at least 15 dB right there. A little enclosure would help a lot too.

GWE

Reply to
Grant Erwin

I think you could isolate vibration OK, but a 3450 RPM fan makes a hell of a racket that would be more of a challenge. It could be done with an acoustic enclosure, but I bet it'd be a lot easier (especially for Gunner) to scrounge up a 1725 RPM motor.

Reply to
Don Foreman

That's a terrible idea, it'll never work. :^)

Hmm. Not sure about the 2.3 kV leg there....

One thing you have to realize is that the amperage you are measuring on the legs (probably via an amp-clamp meter, right?) is mostly reactive power when you are not loading the idler. When you load it by welding, the power factor is coming closer to one, which means it's spinning your meter more. The idea is that the amp clamp does a poor job of showing the real power draw, because the unloaded condition has such a low power factor.

The good news is, the 18 amps you measure with it unloaded is mostly reactive current. You are probably drawing something like 500 watts total when it's not loaded, if my stone age converter is a guide.

Jim

Reply to
jim rozen

I passed up a real nice older airco tig welder because I wasn't sure if I could run it with my rotary phase converter. I have a miller double roller wire feed unit that would have fit on it perfect. Next time I won't let it get away.

Richard W.

Reply to
Richard W.

I'm not sure what you're describing here. A sponge sounds like porosity. In regular spray transfer without Dual Shield, the weld looks like nice, shiny, molten metal- kind of like the stuff the cop was made out of in Terminator. You can put a lot of metal on fast which can lead to gorilla welds if you're not careful.

Reply to
ATP*

Old copper-iron (not inverter type) TIG machines draw significantly more current (at given amperage rating) than MIG machines do. I think you'd need at least 20 HP worth of idler to run a TIG at 250 amps.

Reply to
Don Foreman

Check in with Jerry.

Reply to
Don Foreman

Cool. I'm a bit envious of that welder but I'll get over it someday, probably..

John

Reply to
JohnM

I tried that. Let out the Magic Smoke. I just finished repairing the burned out wires a few minutes ago..and thankfully it still works.

Gunner

"Pax Americana is a philosophy. Hardly an empire. Making sure other people play nice and dont kill each other (and us) off in job lots is hardly empire building, particularly when you give them self determination under "play nice" rules.

Think of it as having your older brother knock the shit out of you for torturing the cat." Gunner

Reply to
Gunner Asch

Lord yes. Down at the 18-22 volt range..its like welding with light. Hardly any sound other than a faint hiss/crackle. I was wondering if I was getting any penetration at all, and sectioned a couple welds. Nice and deep with 75/25 gas. Ill have to try this with Co2 next.

Gunner

"Pax Americana is a philosophy. Hardly an empire. Making sure other people play nice and dont kill each other (and us) off in job lots is hardly empire building, particularly when you give them self determination under "play nice" rules.

Think of it as having your older brother knock the shit out of you for torturing the cat." Gunner

Reply to
Gunner Asch

Im planning on building this into a "unit", Electrical subpanel, etc. Ive got a Clausing 1501 15x48 lathe I havent been able to do much with, as it has a 7.5hp motor on it, which the 5hp will start..but it doesnt like it very much, least of all starting it in high gear.

I simply stuck this together in the most expedious fashion, just to see if it would run the welder well enough to bother going any further. LOL...since I let out the magic smoke on the commercial RPC..my shop has been running on a 5hp motor sitting in the dirt in the middle of the shop with a dryer cord feeding it and a chunk of

12/4 running to the distro panal. Rope start and plug it in quick before the motor slows down. But it worked for an expedient.

Gunner

"Pax Americana is a philosophy. Hardly an empire. Making sure other people play nice and dont kill each other (and us) off in job lots is hardly empire building, particularly when you give them self determination under "play nice" rules.

Think of it as having your older brother knock the shit out of you for torturing the cat." Gunner

Reply to
Gunner Asch

Ayup..it really heavy on fan noise. The wind coming off the fan can be felt at over 20 feet. It was so strong, I had to put up a wind shield so it wouldnt keep blowing my sheilding gas away...10 feet away.

Gunner

"Pax Americana is a philosophy. Hardly an empire. Making sure other people play nice and dont kill each other (and us) off in job lots is hardly empire building, particularly when you give them self determination under "play nice" rules.

Think of it as having your older brother knock the shit out of you for torturing the cat." Gunner

Reply to
Gunner Asch

Cold fusion I think. Or sunspots. Or even a typo. Blush.

Cool!! I try to follow the various RPC threads...but when it starts geting into the reactive/inductive techno stuff...my eyes glaze. Im a screw driver type. Shrug

Gunner

"Pax Americana is a philosophy. Hardly an empire. Making sure other people play nice and dont kill each other (and us) off in job lots is hardly empire building, particularly when you give them self determination under "play nice" rules.

Think of it as having your older brother knock the shit out of you for torturing the cat." Gunner

Reply to
Gunner Asch

Thats why I posted it to both rcm and the welding one. The subject has been a pretty regular one on RCM..but I figure some of the welding folks may have been new to the idea. 10hp should be big enough to run a fair sized TIG or stick welder.

Hummmmm maybe someone will come take the Hobart Cybertig 2 off my hands now. Good machine, 700 amps top end of programable DC Stuff. Includes a plasma torch and gas console. Needs a pedal though. 10pin hobart.

Best offer. Central California, on a cart with flat tires. But it does run and well.

Cheap..really cheap.

Gunner

"Pax Americana is a philosophy. Hardly an empire. Making sure other people play nice and dont kill each other (and us) off in job lots is hardly empire building, particularly when you give them self determination under "play nice" rules.

Think of it as having your older brother knock the shit out of you for torturing the cat." Gunner

Reply to
Gunner Asch

It layed out a bead of metal that looks nothing more than tiny ball bearings all piled up. I had the wire screaming through the nozzel at

35 volts. About 10' a second..chuckle..anything slower with that size wire and it would burn back in a heart beat.

When I had enough fun with that, I turned it back down to normal and made some of the nicest beads with good penetration Ive ever done (which aint saying all that much..sigh)

I burned up all the .035 copper coated that I had in that mad minute, and I had to stick on a roll of .035 dual shield...70s-3 IRRC. Now I got to brush off the flux..sigh.

Gunner

"Pax Americana is a philosophy. Hardly an empire. Making sure other people play nice and dont kill each other (and us) off in job lots is hardly empire building, particularly when you give them self determination under "play nice" rules.

Think of it as having your older brother knock the shit out of you for torturing the cat." Gunner

Reply to
Gunner Asch

Is there any advantage of one rpm motor or the other? Does the slip stream angle of the dangle hodendragon perform better than the lowslide undertow of the invictus bordergary?

Gunner

"Pax Americana is a philosophy. Hardly an empire. Making sure other people play nice and dont kill each other (and us) off in job lots is hardly empire building, particularly when you give them self determination under "play nice" rules.

Think of it as having your older brother knock the shit out of you for torturing the cat." Gunner

Reply to
Gunner Asch

Sweet! Good thing I'm yonder distant. If I tried it I'd surely want one like it.

I'll stoicly mush on with what I have, shrug, sigh...oh poor me...

Reply to
Don Foreman

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