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Miller 250DX power issue

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  • #16
    Power factor is calculated by comparing the KVA to Kw. That is the apparent power to the real power. The power company wants it as close to kva=kw as possible which expressed as a fraction would be 1 if they are the same. The difference is lost in the transmission lines mostly as heat, I suppose. Transformer welders can be particularly bad as are large motors running unloaded(think continuous run compressors unloaded). I think IIRC that the specs on my Idealarc 250 without power factor correction is in the neighbourhood of 65%. Power Factor correction would reduce the loaded (welding) current by 30% and permit using smaller supply wire and smaller breakers, but it will change the idle current draw from 6.2 amps without power factor correction to 23 amps with it.IMO if you are in a situation where you will not be penalized for poor power factor(non-commercial) power I would not use power factor correction but if you are looking at monthly fines for poor power factor(commercial power) I would use power factor correction. I certainly don't weld continuously enough at home to justify power factor correction so the machine idling "on" but not welding while I re-position stuff, grind or whatever means I would use more total power if I had power factor correction than without it.
    That said the new "smart meters",I'm told, are capable of delivering power factor information to the power supplier. The old single meters were not but they were designed when most domestic power consumption was resistive loads and power factor for houses was not a consideration as most were pretty good. The world has changed and we may see a time when the utilities may start to penalize homeowners for poor power factor usage.
    It is my understanding that inverter machines are very efficient and as well as being able to perform various customizations of your arc, will keep your utility happier.---Meltedmetal


    • #17
      So it's pretty close to what I thought, minus the technical stuff. Not that long ago I passed on a decent deal on a dialarc 250 HF-P because of that. Wasn't sure if you could just unplug that stuff inside or not. Guess you can, depending on the machine of course.


      • #18
        never drawing 60 amps at idle, thats just a ghost reading, whats happening is that the PF caps are charging. this eliminates any surge on the line once the machine is up and running. and yes industrial machines are being used constantly, unlike garage machines which are used erratically and often turned on and off, so the caps would charge then discharge when shut off, only to have to recharge when turned back on.