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3 phase inverter on single phase

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  • Willvis
    started a topic 3 phase inverter on single phase

    3 phase inverter on single phase

    I'm wondering if anyone has any experience with running a 3 phase inverter machine on single phase. Specifically the machine I want to run is a lincoln 455m/stt(I know, miller forum... Lol) I picked one up for pretty cheap, didn't really think to check out the phase requirment. Honestly I thought at the time all the inverter machines could run on single phase. All the ones I looked at in the past could run on single phase, I guess I never looked at anything this big.

    The machine does power up on l1 and l3 connected to single phase. I can connect the power wave software, even updated the firmware. The manual mentions reduced output on single phase which leads me to believe it will run, however one lincoln rep I talked to said probably not. I dont have the feeder that is required to test it, all controls are on the feeder. Really the first thing the machine does is run the input into a bridge rectifier so I dont really see why it wouldnt work. Only reason I can see is that the input lines are taped with small wires to a control board so it could complain when it sees single phase. I could probably remove those lines from the input and run them off a cheap/small vfd to trick the machine into thinking its getting 3 phase.

    Anyways so I have a few options.
    1. Try and sell it as is and buy a single phase machine. Could be a hard sell without a feeder or proving it works.
    2. Buy a used feeder(if I can find one) and sell it. Hopefully turn a small profit.
    3. Buy a used feeder and try and run it on single phase. Its like almost a 600 amp machine so even if I can get half the output its probably good for me. I just wanted something the can do pulsed mig.
    4. Say screw it. Take a risk on a new feeder and try run it as is. Worst case scenario maybe I would need a phase converter.

    I guess Im leaning towards try to find a good used feeder then try and run it.

  • Willvis
    replied
    lol. I'm in the same boat. American rotary makes some nice 3 phase converters. They claim 5% max voltage variation between phases which they say is as good as the power company.

    Leave a comment:


  • ryanjones2150
    replied
    That's exactly what it was! I like Wayne's idea...bobcat 3-phase is on the list!

    ...ya, not really. I'll just suffer through on single phase, like the low rent fab/repair shop I am...

    Leave a comment:


  • Willvis
    replied
    Originally posted by ryanjones2150 View Post
    I called the power company a couple years ago and asked about getting 3 phase brought in to the shop, the guy in their engineering department said, "no problem! $15,000."

    ...no thanks.
    Same here. 15, 000 just for the transformers.

    Leave a comment:


  • Aeronca41
    replied
    Originally posted by ryanjones2150 View Post
    I called the power company a couple years ago and asked about getting 3 phase brought in to the shop, the guy in their engineering department said, "no problem! $15,000."

    ...no thanks.
    I had the same experience. For that price, you could buy a Bobcat 3-Phase and a LOT of gas.

    Leave a comment:


  • ryanjones2150
    replied
    I called the power company a couple years ago and asked about getting 3 phase brought in to the shop, the guy in their engineering department said, "no problem! $15,000."

    ...no thanks.

    Leave a comment:


  • FusionKing
    replied
    Not only do I have 3 phase, it is 800 amp service at that.
    I just lucked out renting the place and then buying it from the bank after the landlord signed it over to them.

    Leave a comment:


  • ryanjones2150
    replied
    I wish I had 3-phase power in my shop....lucky dogs....

    Leave a comment:


  • FusionKing
    replied
    Good job of pressing onward in spite of naysayers.....
    Even proved it with a weld
    That is a very unique machine you have. Too bad all 3 phase units can't be similar.
    I run any miller inverters we have on 3 phase almost all the time.

    Leave a comment:


  • Willvis
    replied
    Lol! I don't think all 3 phase inverters are going to run on single phase. I was looking at the specs on some millers that were 575 or 460 volts only. Maybe some other lincoln units aswell. Atleast anyone looking for info on this particular machine might find this useful.

    Leave a comment:


  • Noel
    replied
    Originally posted by Willvis View Post
    Just figured I would let everyone know that I got this machine up and running on single phase. No modification required, but the machine limits its output to 325 amps. I found a used feeder for 2 grand so about half the price of new. Had to add a gun and a drive roll kit. So I'm in it for about 3500 which I think is pretty good considering the machines capability. I got the dual feeder aswell so that will be nice for setting up the other side for aluminum. Heres a pic of thr machine running and a quick test weld using the pulse program on 0.045 solid wire.
    LMAO!!! I've waited a long time to hear that news. You sir, have done the welding community a great service. I commend you. Brightened my day.

    Leave a comment:


  • Aeronca41
    replied
    Good work! Success is sweet!

    Leave a comment:


  • Willvis
    replied
    Just figured I would let everyone know that I got this machine up and running on single phase. No modification required, but the machine limits its output to 325 amps. I found a used feeder for 2 grand so about half the price of new. Had to add a gun and a drive roll kit. So I'm in it for about 3500 which I think is pretty good considering the machines capability. I got the dual feeder aswell so that will be nice for setting up the other side for aluminum. Heres a pic of thr machine running and a quick test weld using the pulse program on 0.045 solid wire.

    Leave a comment:


  • Willvis
    replied
    It has to be connected to l1 and l3 for sure. It wouldnt turn on otherwise. Ive been posting about the filter caps on an electronic forum and I think I found some that will work. They are huge and a bit expensive but would still be worth it.

    I was wondering the same thing as you about the rectified voltage. Everything online seems to indicate it would have an output of 340vdc. Im going to put the volt meter on the rectifier and see what it reads. Also in the software it tells you the voltage of 2 capacitors and they say they are at 360v dc.

    Ok now for the confusing part that Ive been wondering about. On 3 phase your line to line voltage reads 208v rms but it is still 120v line to neutral. On single phase(split phase) its is 240v. The 208v reading has to do with the 120* out of phase nature of 3 phase. Therefore I think the peak voltages of the 2 would be the same. The peak voltage is what you end up with when you rectify the ac and add the filter caps. So on the machine there is a jumper wire to select 208v input of 240v input. The question then is what to put the jumper wire on. My gut tells me it should be on the 208v setting. Anyways thats probably just a matter of trying both settings and seeing what works. I dont think its gonna damage the machine either way.

    Leave a comment:


  • MasterKwan
    replied
    Originally posted by Willvis View Post

    It all kind of implies it would run on single phase. Realistically the first thing it does is run the line power through a rectifier. It would be dc past that point wether incoming power is single or three phase. Only difference would be single phase is going to have alot more ripple on the dc. I could smooth it out with some big capacitors.
    They were specific about L2 so I'd experiment with hooking the 220 to the 2 other phases. Like you, I think it's just a matter of ripple. It depends on how good their filter caps are on the output of the rectifier.

    You know 220 is really 2 120 volt wires that give you 220 between them. When you hook up 220 like this to a 3 phase welder, doesn't that mean the output of the rectifier is 120 DC instead of 220 dc?

    Leave a comment:

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