Inside the Powercraft...

  1. simon718

    simon718 needs to stay off ebay

    Messages:
    2,015
    Norn' Iron
    ...if anybody was wondering :whistle:

    [​IMG]

    [​IMG]

    [​IMG]

    not exactly the most sophisticated machine in the world, and a lack of smoothing caps... and that fan is absolutley pathetic, next week's task is to source something a little bit more substantial, hopefully make it run a bit longer before cutting out:whistle:
     
    Larry Boorman likes this.
  2. R Kraft Member

    Messages:
    895
    Wyoming,USA
    Cheapwelder improvements

    Your Powercraft looks a lot like the Harbor Freight welders.
    I've put muffin fans in my welders,they run a lot cooler.
    Does the little thing have diodes, to make it DC ?
     
  3. zzr1200

    zzr1200 Working at 650 ft on open steel work

    Messages:
    3,529
    Location:
    Brimington, Chesterfield, Derbyshire
    What the fooks a "Muffin Fan"......:dontknow:.........:confused:
     
  4. shenion

    shenion Tool Pack Rat

    Messages:
    7,588
    Location:
    Stone Mountain, GA USA
    Also called a box fan:
    [​IMG]
     
  5. rtbcomp

    rtbcomp Moderator Staff Member

    Messages:
    18,615
    Location:
    Sheffield UK
    That fan is awful, and the transformer laminations look skewed. If it's AC it won't have smoothing caps!
     
  6. simon718

    simon718 needs to stay off ebay

    Messages:
    2,015
    Norn' Iron
    Ah i stand corrected, its ac, what do ya expect for 30 quid haha. Shenion that looks alot like a computer fan? Although they are obviously low voltage...
     
  7. rtbcomp

    rtbcomp Moderator Staff Member

    Messages:
    18,615
    Location:
    Sheffield UK
    Box fans come in 5v 12v DC 110v and 220v AC and no doubt others to order.
     
  8. R Kraft Member

    Messages:
    895
    Wyoming,USA
    The fan on his welder is a thing of beauty, compared to the original on mine.
    But I wouldn't have been able to put the other stuff in without changing it.
    Amazing how much stuff you can shove into a $140. welder case.
     
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  9. simon718

    simon718 needs to stay off ebay

    Messages:
    2,015
    Norn' Iron
    robert... thats a shockingly *NO SWEARING ON THIS FORUM* origional fan in your welder :hug: what all mods have you done to it??
     
  10. Damaged

    Damaged I blame the penguins.

    Ehm,

    Wouldn't money be better spent buying a decent welder in the first place? :scared:
     
  11. simon718

    simon718 needs to stay off ebay

    Messages:
    2,015
    Norn' Iron
    not if you can scavenge the stuff/ get it cheap enough :clapping: and the proper welder i want/intend on getting (lorch inverter) is over £500 so a few quid spent on mods to the cheap welder gives an improvement in the short term till i can afford better :cool:
     
  12. R Kraft Member

    Messages:
    895
    Wyoming,USA
    It has an 80,000mfd capacitor from a communication system.
    400 amps in high efficiency diodes from a piece of 3 phase medical equipment.
    A heat sink on the diodes from a vfd driver from the heating system at a local school.
    A 117cfm axial fan off of a scrapped tanning bed.
    I split and regulated the wire feed motor drive voltage and made a stepped (3 speed) voltage, from 0-40,0-200,0-400 ipm of wire.
    Added a 200uf capacitor across the wire drive motor to reduce the back emf pulses on the motor and smooth the voltage.
    Replaced the nylon wire feed tube with a steel one from an old miller welder.
    And I left the switch connectors so that I could use a spool gun.
    The open circuit voltage went from 38 to 55 but all of the components are running with a good safety margin.
    I spent about $25 on the modifications,wire and shrink tubing and such.
    Spent about 8-12 hours of time,if you don't count the time scrounging parts.
     
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  13. shenion

    shenion Tool Pack Rat

    Messages:
    7,588
    Location:
    Stone Mountain, GA USA
    Did similar to my CP-250, I added 60,000uF in 2 caps. Used flattened copper pipe as bus bar between caps and used 2 ga wire to bridge. Your wires look small ;). The CP-250 is 2' wide, 3' tall and 3'deep and it was tight fitting in the caps ;)

    It did change the OCV considerably, but it still welds at about the same voltage. I did find on 0.6mm wire the voltage has to be turned considerably lower.

    I have 23,000uf X 5 for my DIY welder but could only fit 2 in right now ;)
     
  14. R Kraft Member

    Messages:
    895
    Wyoming,USA
    I used smallish wire to the capacitor,based on the percentage of the actual power that was ripple.
    The welder is only rated at 115amps at 15% duty cycle, with the original parts.
    The fan should do wonders for the duty cycle,I can feel a good breeze coming out of the vents.
    It should have 10-20% more power with the capacitor.
    It is strange that they build something that is supposed to be a linear supply,without a capacitor.
     
  15. JML

    JML Member

    Messages:
    103
    Northumberland
    Did you leave room for the flux capacitors and di-lithium crystals:laughing:
     
  16. shenion

    shenion Tool Pack Rat

    Messages:
    7,588
    Location:
    Stone Mountain, GA USA
    Yes, the reason they dont have caps is they are expensive and will wear out. Mine are about $50 each for high-current and high-current grade.

    To get any real smoothing (what a linear supply would have.) will take at least 4x what you have. I figure mine make a difference up to about 60 amps. The main reason for adding them was increased arc stability as it was a 3-phase welder run on single phase. The arc has very little buzz.

    at only 115A, it should be enough. Mine is rated at 330A max, so I wanted more.
     
  17. ARCEYETHENOO

    ARCEYETHENOO Member

    Messages:
    2
    HOLLAND
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