554,275 active members*
3,410 visitors online*
Register for free
Login
Results 1 to 4 of 4
  1. #1
    Member
    Join Date
    Jul 2022
    Posts
    2

    Off grid CNC plasma?

    Hello all, building a shop hopefully off grid, however I can not find any reference points for this build. Looking at various plasmas preferable one with pipe cutting abilities. Will most likely go with a Torchmate 4400 with pipe cutter. There are a couple other brands that are appealing though.

    Here’s the magic question, does anyone know what it would take to run this machine for say a couple hours a day, this won’t be a production shop, I am a industrial designer by trade and mostly specialize in one off projects. I am looking into cutting some heavier plate, most likely not exceeding 1/2”. Some minor structural stuff like framing for shipping containers builds, brackets etc. I know many variables determine an exact calculation I’m just baffled I can’t find the discussion at the least. Any direction with this would be honestly appreciated.

  2. #2
    Member
    Join Date
    Nov 2013
    Posts
    2021

    Re: Off grid CNC plasma?

    Hi,
    plasmas require a s****tload of power.

    Lets assume a cut current of 50A and an arc voltage of 100VDC.
    The power of the arc is 50 x 100=5000W or 5kW.

    If the plasma machine is an inverter style it may well have a power factor of 0.7 or less so the load on the supply is going to be:
    5000 / 0.7 =7142W or 7kW.

    You'll need on hell of an off-grid supply and a load of storage to run a plasma of any description.

    Craig

  3. #3
    Registered
    Join Date
    Nov 2012
    Posts
    1223

    Re: Off grid CNC plasma?

    Keep in mind that the plasma cutter will also need compressed air. That adds at least 2kW to the power budget, unless a suitable air compressor is already accounted for.

  4. #4
    Member
    Join Date
    Jul 2022
    Posts
    2

    Re: Off grid CNC plasma?

    Thank you for the feedback, per my post I meant to say Cutting material up to 1/2”.

    So let me kinda tell you where I’m at overall, I picked up some raw land in AZ. Currently roughing in utilities, Trying to bypass hard lining with the local power company for various reasons. Solar companies are abundant, including online kits, however it doesn’t seem any of the tech,s are familiar with actually designing systems beyond basic homes, nor do the machine companies have any reference points. Without getting into quality or solar components, mainly the batteries and or adding a generator to back the system up. With my limited knowledge I know one thing is for sure. I need to figure out what the max draw would ever be from the system. Surge start,Surge peak and the constant. I’ve tried asking the solar companies to configure a system to best function as a 200 Amp panel would, with the ability to add another 200 on top, single phase, at a later date, anyways, from a base stand point this system would periodically need to handle,

    -CNC table/laptop 4400
    -CNC plasma torch flex Cut 80
    -80 Gal Compressor (make?)
    -low ambient A/C (Make? cooling approx 400sqft)

    -In home refrigerator (make?)
    -in home freezer (make?)

    I know there is lots of detail needed to precisely dial this In but With those additional items in mind. While keeping this as simple as possible just so I can start gathering an idea of cost. Do you see a kit from

    https://www.solar-electric.com/resid...olar-kits.html

    That could work? The company is northern Arizona wind and solar, again without getting into brand qualities just from a numbers stand point would be great to get a ball park to run the items above with the A/C only being a summer thing and I have the flexibility to not have to work with the CNC everyday and again never more then a couple hours of run time Daily. Running 400amp single phase With SVECC power 1,500’ into the land with a transformer/meter is pretty close to 30k not including wiring from panel to etc. I know Solar costs more but again for minimal use with time available to let a system Re recharge Daily. From that solar link, does it look like any of those could do such a thing? Renogy could be an option also, I know battery cost can be offset with using a generator instead of trying store all the power. Just wondering if there is a way to guesstimate how much more then 30k it would probably be to achieve this off grid.

    Thank you for your time

  5. #5
    Member
    Join Date
    Nov 2013
    Posts
    2021

    Re: Off grid CNC plasma?

    Hi,
    I think trying to run a plasma on an off-grid system is unrealistic. An 80A plasma could draw 10-20A per phase in a three phase system.
    A Hypertherm 45 is the biggest single phase unit that I know of. 45A plasma will cut 1/2 inch, but slowly. All the while it will be drawing 25-30A
    from your single phase supply. That is not a good candidate for off-grid. Your plasma and compressor would need to be driven with generator, and a decent one
    at that. If you have a marginal generator you'll blow the plasma to bits.

    AirCon, fridge and freezer, yes no trouble at all, off grid systems are all about those sorts of loads, but an 80A plasma....forget it.

    Craig

  6. #6
    Community Moderator Jim Dawson's Avatar
    Join Date
    Dec 2013
    Posts
    5601

    Re: Off grid CNC plasma?

    Lets break this down a bit

    -CNC table/laptop 4400, About 1KW

    -CNC plasma torch flex Cut 80, per the manual @230V, 62 Amps, 14.25KW max

    -80 Gal Compressor (make?), About 5KW. Mine draws 23 Amps at full load on the single phase side, it's a true 5HP compressor, ~19 SCFM@90 PSI. Per the Flex Cut 80 manual, 5 SCFM@90 PSI minimum required, but you don't want it running continuous. Air compressors are rated by SCFM/HP, not gallons. I hate what the marketing people have done to the specs. Yes, you could put a 1/2HP compressor pump on a 80 gallon tank, but you would still have a 1/2HP compressor. I have about 260 gallons of air storage capacity, so that must mean I have a huge compressor

    -low ambient A/C (Make? cooling approx 400sqft), For the shop? About 1.5KW


    -In home refrigerator (make?) 0.25 KW max

    -in home freezer (make?) 0.25KW max

    So adding all of the above = 20.75 KW, 20750W / 230 V = 90.2 amps. Add 10% for overhead, = 100 A minimum required

    Solar/battery/inverter system should handle the refrigerator, freezer, lighting, and small air conditioning and other normal household type loads. But when you kick on a 5HP air compressor and the plasma torch, you are going to need a generator. A 30KW Diesel or propane generator should handle the load. If you can find a low time military surplus unit, those things are tough and are underrated so will output a lot more intermittently.

    Add in electric water heating at another 4.5 KW intermittent. My home/shop winter time load is about 35KW max, including electric heat, or about 150 Amps. For summer cooling I only have one small window air conditioner in the bedroom. We don't need it much up here in the northwest.
    Jim Dawson
    Sandy, Oregon, USA

  7. #7
    Member
    Join Date
    Nov 2013
    Posts
    2021

    Re: Off grid CNC plasma?

    Hi,
    for some (seven) years I worked for a company that sold and serviced welding equipment.

    We had an extensive hire fleet. In particular we had three Lincoln 575 Generator/Welders. They were capable of producing 575A welding, and I would test them to that limit
    and can guarantee that they did produce 575A continuously for extended periods. They have a 50-60hp four cylinder diesel engine, and on a trailer arrangement you can tow with a car.
    In addition to the weld output they have a 20kW three phase auxillary output. We had Hypertherm 85's, Hypertherm 105's and a Hypertherrm 125 plasma for hire. We absolutely insisted that if
    using the 575 as a power source that the plasma be (three phase aux circuit) used but absolutely not similtaneously as the with the weld output. This was because with both running the voltage could
    sag and the electronics would come under severe stress.

    The Lincoln had two DC choppers at $2000 each and the power board in the plasmas ranged from $3000-$4000. If the voltage sagged all of these were at risk of blowing up.

    These Lincoln 575's are big and very capable machines but the big Hypertherm plasmas made them 'sit back on their heels', don't be tempted to skimp on generator power or you will
    blow your plasma to bits, I've seen and repaired the damage before, it's not pretty.

    Craig

Tags for this Thread

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •