looking for help with old school Plasma Cutter
RSS | Subscribe | Contact Us | Advertise | About Us
Results 1 to 5 of 5
  1. #1
    Join Date
    Jul 2015
    Posts
    37

    looking for help with old school Plasma Cutter

    I need some help with an old school, transformer based plasma cutter I'm breathing new life into.

    This is not intended to start a debate on inverter vs. transformer and why one should buy an inverter because they are more efficient, lighter, cut cleaner etc. etc. I understand all that, and largely it is true, IF you buy a quality machine (not so much the Chinese imports). But I didn't want to spend $$$ on a new, high quality inverter plasma as I am just a hobbiest and don't depend upon the machine to make a living. But it's really because I like restoring old tools and I like machines that I can repair myself. I'd rather own a USA made old school tool than a cheap, poorly made import no matter how modern. Replace a transformer easy, fix a PCB which has readily available components easy, solenoids easy etc. Anyway, I wan't shopping for one, but a plasma right up my alley pops up locally and I couldn't resist.

    Seller hooked up a tiny air compressor and demonstrated the plasma cutting 3/8” plate, price was right so I bought it. But, I do have a bunch of questions since I can't find much on the web about this unit. If some of you could help I would appreciate it.

    Model is NAPA 83-330, also sold as a Marquette 12M-200, I believe it was made by Century, and as many of you I'm sure are aware, Marquette/Century was acquired by Lincoln some time ago.

    220V 40 (or 50?) amp machine. High frequency start I believe.

    1) Has only 2 switches on the machine. Power, and “Setup”. I have no idea what the setup switch is for. Seller said he did not know and never used it. After some research, I now think it is simply to open the air solenoid/valve to purge the system of any water vapor prior to use, but really not sure.

    2) What are the air requirements/ideal settings? I read that most require 80-100 psi at about 8 cfm, but I really don't know. My 2 compressors: 60 gallon 125 psi 10.2 cfm, the other is a contractor size compressor but high duty cycle, it will produce 125 psi 3.2 cfm, has only 4 gal tank, but 100% duty cycle. Will these compressors be enough? Would love to be able to use the smaller one.

    3) I believe the machine has high frequency start because I see a set of points in there. What should the point gap be set to? I've read most are set at .028-.035, but who knows?

    4) This is where I really need help...the torch and it's connections/function. The machine came to me with 2 torches. Connected at the time of demonstration was a cheap PT-31 torch. Seller said you had to scratch start it, which he did, and that does work, but once I got the machine home and opened up, I see points, so I wonder, why not high frequency start it? Is this torch not capable of that? Do the points just need adjustment, or is hi freq not working? The second torch the seller tells me is the 'original'. Original in quotes because he really isn't sure, he bought the machine used with the 'original' torch on it, but soon afterwards replaced it. He replaced it because the 'original' torch had 2 buttons on it. High and Low. He didn't like that because he said they got in the way, always hitting wrong button etc. I have never seen a torch with 2 buttons, but it sort of makes sense because there is no amp adjustment anywhere on the machine itself. Has anyone ever seen a torch like this? Upon opening the machine I see a diagram and connection points that could be for a Hi/Low torch switch. (pics attached in this and next post). Does anyone know how to connect this 2 button torch? Ultimate goal for me would be to reconnect the 2 button torch AND get high freq start working.

    5) Lastly, why is it that OEM consumables are 50x the cost of the generic imported pt-31 consumables? I suspect the OEM parts are higher quality but 50x ?? (not a typo). Are the generic consumables total junk?

    Thanks
    Attached Images Attached Images      
    Last edited by AnOldman; 04-14-2019 at 05:02 PM.

  2. #2
    Join Date
    Jul 2015
    Posts
    37

    Re: looking for help with old school Plasma Cutter

    3 more pics
    Attached Images Attached Images    

  3. #3
    Join Date
    Mar 2010
    Location
    Ceres, California
    Posts
    3,399

    Re: looking for help with old school Plasma Cutter

    Set switch is for turn air on and setting the air regulator to 60 psi before cutting.
    Was going to send you to Lincolns web site to get the owners manual but the brand new manual system
    is not working right. You type in 83-330 and it tells me what machine it is but won't let me access the manuals. spark gap is 0.022.
    This plasma is a HF pilot only torch. When you press the start switch you may only have air at the torch.
    No visible arc. But is a darkened room you may see a small blue flame. It only comes out about 1/8 inch.
    So if you press the start button with the torch about 1/8 above clean metal the arc will jump and start cutting. When cutting on dirty rusty or painted metal, it can be done but you have to sand a starting place down to clean metal. torch head looks like an ESBA pt31 torch, which should be able to be converted to a 31xl torch.
    So send me your E-mail here by private message. I have all the manuals in a older system. All are to large to post here.
    Or if you can reach the century group at lincoln they will e-mail a copy of the manuals. Get all 3 manuals.
    owners, parts and service.

  4. #4
    Join Date
    Jul 2015
    Posts
    37

    Re: looking for help with old school Plasma Cutter

    Wow. Thank you so much for the info. I will contact you via PM.

  5. #5
    Join Date
    Jul 2015
    Posts
    37

    Re: looking for help with old school Plasma Cutter

    Got manuals from Lincoln today. Lots of questions answered. Looking good now. Thanks.

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •  
RSS | Home | Penton Media | Contact Us | Subscribe | For Advertisers | Terms of Use | Privacy Statement