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MP-45E and Haas-Kamp, RPC, or should I sell?

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  • MP-45E and Haas-Kamp, RPC, or should I sell?

    Just to let you know, this is a x-post from the practical machinists forum.

    Hey there,

    I am somewhat new here (and pretty new to welding as well). I picked up a MP-45E Generator, and a Millermatic D-52A (Not S) wire feeder for a somewhat good price. Right now, my home doesn't have 3 phase power (Canada, sigh...) but I do have around 240V at 400A available to me at the breaker due to an uncompleted addition. Pretty much my question is: Since I don't have 3-phase, should I sell it (and make a small profit), try to convert it (I believe it has been done before), or build a rotary phase convertor? I have the electrical skills to complete the last 2 (I work construction, and high voltage mains is just something I deal with), so what do you think? Is it a worthwhile machine to keep? Thanks!

    EDIT: I should say that both were purchased in 1983, I don't know the exact manufacture year on the MP-45E yet, hopefully soon though.
    Last edited by TrendMend; 06-27-2020, 01:32 PM.

  • #2
    Hi TM, I have done a few H-K conversions on the CP-300 and CP-250TS, which use a variable "tap" slider on the transformer output, and work well with the conversion (awesome with .045 FCAW-G). The MP-45E uses a saturable core reactor/magnetic amplifier (like the SRH-333 or SRH-444) to control the output. I have seen some successful SRH conversions, which means MP-45E may work well, though the transformers, or at least output stabilizers, are probably designed a little differently between the MP-45E and SRH to give a constant voltage instead of constant current output. I will add that the newer solid state 3-phase (Lincoln DC-600) don't seem to work well with the H-K conversion across the power band, and really only work well in a narrow band based on what capacitance you connect in series with the middle leg of the transformer. It's likely because the transformer stays in it's linear region (away from saturation) and it's properties are static because the SCRs do the control. The older CP's changed characteristics with the sliding output "tap," which worked well with the H-K. The MP-45E to me would seem to behave more like the newer solid state, but I haven't done testing and the SRH performance on H-K says it may work. It's probably a $100 gamble in parts on top of purchase, and the mods are reversible. Since it's a three phase in Canada, I would think it would be tough to sell, so hopefully the purchase price is close to nothing.
    Last edited by jjohn76; 06-28-2020, 02:42 PM.


    • #3
      Hey there,

      Thanks for the very detailed response! I saw you responded but it took a couple of days before it actually showed up on my end. I grabbed it for much less than the value of just the wire feeder or even the accessories, so if I do sell I shouldn't be at a loss. Mr. DaveKamp responded a little after you, and I'll be taking both of your responses into consideration (they are almost identical, except yours is much more detailed). If I continue with the conversion which I probably will, I'll continued to keep this updated. Hopefully we can see how it compares to similar conversions.


      • #4
        Sounds good.