[AKmud]

So, I have a Syncrowave 250DX that I am running off a 50A circuit. I am not able to weld at high amperage for more than an inch or two obviously without blowing the breaker. I've been reading up on the PFC option but I haven't had anyone be able explain the 47A draw at idle. Some guys say it is hard on the electric bill and others say it doesn't really affect electrical usage because of some sort of phase correction or something that actually cancels out amperage while idling.

Does anyone have experience with this add on? Does it really draw a true 47A all the time? Does the electric bill suffer?

I'm trying to figure out if this would be a worthwhile add on.

[MinnesotaDave]

I've wondered about this since my Airco tig has power factor correction. I've since asked many questions, done a lot of reading, and attempted some of the math.

My summary (as an electrical layman) - it will reduce your overall peak amperage needed so you can run off a smaller breaker.
My Airco 300 (miller 330 abp) is on a 60 amp breaker and I have yet to trip it at 230 amps AC tig - if that helps.

Also, it will not increase your power bill. This statement has been backed up by research (reading long boring technical articles) and some electricians.
It will not really save you any big money on power either. The cost saving comes mainly from not paying the penalty fees for not having it installed (mainly only big companies pay those anyway).

Now, for those who would like to engage in a heated debate over my statements, I do not have the technical knowledge for it, I would just be cutting and pasting from articles

Some reading:
http://en.wikipedia.org/wiki/Power_factor
http://www.onsemi.com/pub_link/Collateral/HBD853-D.PDF
http://www.hearneng.com/WhitePapers/Doe ... 0Money.pdf

[AKmud]

Thanks Dave, I have been trying to find someone who had experience both before and after the PFC install. I may have to give it a try. Running higher output off my smaller breaker is my goal.

[MinnesotaDave]

Thanks Dave, I have been trying to find someone who had experience both before and after the PFC install. I may have to give it a try. Running higher output off my smaller breaker is my goal.

Smaller breaker is the one thing we can be certain of, fortunately they listed it in the manual.
...the rest of the technical stuff involved in PFC borders on magic

[WerkSpace]

Here are a couple of videos that will help to explain the magic.
http://www.youtube.com/watch?v=dPFKcUxbNuQ
http://www.youtube.com/watch?v=81n7HrLn3Ng

[PeterM]

Power factor is caused by inductive loads in AC circuits. Motors, transformers and older lighting ballasts are inductors. If you look at the nameplate of an electric motor you will see that the output power (the rating of the motor in H.P.) is less than what you get if you multiply the voltage by the full load current. My compressor for example is 10hp. There are 746 watts in a HP so the motor is 7,460 watts. It runs on 240 volts and it draws 40 amps at full load. 40x240 =9,600 watts. Two reasons for the difference are efficiency (nothing is 100% efficient) and power factor or the Reactive power of the motor, caused by the inductive windings in the motor. There is a power triangle for motors called true power, apparent power and reactive power. True power is the output power, apparent power is what it draws from the supply and reactive power is the difference, but is a vector sum not just the difference between the two numbers, right angle triangles, trigonomotry, pythagoras's theorem and all that. Capacitors have the exact opposite effect on a circuit as inductors do. So power factor correction is adding capacitors to a system or individual device to counteract the effect of the inductive part of the circuit, reducing the reactive power and lowering the current draw from the supply while having no effect on the output of the device.

[MinnesotaDave]

Hey PeterM - sounds about right based on the research I've done, but did you answer his questions?

Reading your answer reminds me of a quote:

“A mathematician is a device for turning coffee into theorems.” -- Paul Erdos

Maybe some decaf next time - lol

[noddybrian]

I don't have this welder to prove this one way or the other - but in layman's electrical terms I don't believe just adding some capacitance to the supply can make the unit draw that much idling - as a matter of interest what does it draw when not welding now ? obviously a transformer based machine has a noticeable mains load when idling - but if it draws 47 amps @ 220 volts that's just over 10kw of power - it can only be lost as heat - now even with a big fan you can't be losing 10kw all the time it's on - it would overheat without you welding !- so I doubt that it's anywhere near 47 amps - as to whether adding capacitance will solve your line current limitation - I doubt it - I worked a couple of places with large capacitor banks - but this was solely to keep the power company happy as there were large motors being started which causes them problems - with the lowish cost of capacitors if this was a solution for small domestic loads & saving money I think we'd see alot more about the subject & almost certainly a whole bunch a firms trying to sell them as the newest miracle - my guess is that the efficiency of of a transformer is fairly fixed by design & the output power required - you sadly don't get something for nothing & if Miller offered power factor correction as an option it was probably for industrial settings where if you had a dozen or more in a shop running the power company would require it - unless you can find someone that actually has your machine & can state 100% it works as you hope I think I'd save the money against buying an inverter or upgrading you supply.

Just an opinion - sure others here are better qualified.

[Arizona SA200]

I also have a sync 250 DX and when i built the shop i contacted miller about wiring. they asked for the SN and said i needed a 125 amp breaker so that is how shes wired. I did put in a service disconnect at the recep just to be on the safe side. I wonder if i really need the 125? Not sure my machine has the PCF.

[Arizona SA200]

Sorry PFC.

[Otto Nobedder]

I also have a sync 250 DX and when i built the shop i contacted miller about wiring. they asked for the SN and said i needed a 125 amp breaker so that is how shes wired. I did put in a service disconnect at the recep just to be on the safe side. I wonder if i really need the 125? Not sure my machine has the PCF.

I'm not surprised.

We have 250DXs at work, on 480 3-phase, and still on 30A/leg fuses. And I've still once blown a fuse running wide open HFAC for a minute too long. (Wide open HFAC on a 250DX, for those not familiar, is 310A.)

Steve S

[Arizona SA200]

I'm not surprised.

We have 250DXs at work, on 480 3-phase, and still on 30A/leg fuses. And I've still once blown a fuse running wide open HFAC for a minute too long. (Wide open HFAC on a 250DX, for those not familiar, is 310A.)

Steve S

I've run it wide open at 310 and never had a problem. Its wired 220 single phase. Bad part is the water pump took a crap. Ive got a friend that lets me use his dynasty 300 if i need it and its an awesome machine. I really want the 350.