Synchrowave 250

[Arbo]

I'm still studying TIG machines. My shop runs a sub-panel off of the main 200A panel in the house. What size breaker do I need to run the 250. I realize that an inverter type machine draws much less amperage, but I have ruled that option out.

[BillC]

Look it up in the Owner's Manuals on the Miller weldsite...

[Scott V]

Arbo,when I had a Esab 252 it ran fine with a 90 amp breaker.If you are pushing it over 250 amps all the time with the wave balance jacked over you might go bigger.

Do you just feel more at ease with a transformer tig?That would be only one or two reasons to buy one for me.The other good reason is you can't just pick one up,and walk off with it.
You should have the second one covered with your junkyard dog.

If you look at Inverters power draw at the very top of the power output they start to even out some to the transformer machines.That's something nobody talks about.

[Hobart Expert Rock]

ARBO......... CURRENT DRAW ON 200 VOLTS IS 110 WITH OUT POWER FACTOR CORRECTION CAPS, WITH THE CAPS IS 82, ON 230 WITHOUT POWER FACTOR CORRECTION CAPS IS 96 , WITH POWER FACTOR KIT IS 71................I ALSO HAVE IT FOR 460 AND 575 IF YOU REQUIRE THAT INFO.................REGARDS AND ENJOY YOUR DECISION.....................ROCK................. ...
[email protected]

[houdni]

whats power factor correction? i just bought a sync. 250 and want to wire it to the shop, but i dont know which rating to go with. do i go with pfc with or without? how do i know which one to go with for amperage draw? could someone explain to my the novice. thanks

[Mike W]

Power factor correction is adding some capacitors which will drop the total current draw from the line, but........with the welder just sitting there turned on but not welding, you will be drawing around 55 amps.

If the caps could be switched in while you are actually welding, I could see doing it. I have the Syncrowave 250 at work and like it. I just think it is more reliable compared to an inverter.

[houdni]

thanks mike

[uncrichie]

MikeW, how can it be drawing 55 amps idling. That would be close to 13,000 watts of heat going somewhere? Uncrichie...

[Mike W]

Let me try to explain this. Amps times volts = apparent power or VA. Amps times volts times the cosine of the power factor = true power. That is what your watt meter is measuring.

I don't know what the true power consumption would be at idle with the power correction caps connected. It can be measured but it takes more then a voltmeter and ampmeter. When you have inductance like a transformer in a circuit, there is a phase shift between the voltage and the current. The cosine of the angular difference is the power factor.

The main point is that while you are not drawing as much power as volts times amps would indicate, you still have to size your wire to handle the total amps. I hope this makes some sense.

[uncrichie]

Mike I totally understand induction and phase relationship and the proper sizing of conductors. However I find it a little misleading to say that with the welder turned on and just sitting there it is drawing 55 amps. I don't believe that to be possible. Maybe a spike at initial turn on due to winding resistance but not at idle. Just my $.02. Uncrichie...

[Mike W]

The 55 amps is from the owners manual. I agree that it seems high.

[uncrichie]

Mike, just went to the Miller site. WOW, I can't believe it. Where could all that energy be going? If not being use as the end product ie. the weld, I would suppose its given off as heat somewhere. That incredible. I certainly wouldn't leave that machine on unless I was using it, lots of wasted money. Never welded at 300 amps but that sure looks like the machine to do it! Oh well, I learned something new today. Uncrichie...

[BillC]

It would be interesting if one of the 250 owners would put an ammeter on their input cord, wouldn't it???

Regards,

[uncrichie]

Bill, that sure would be the final answer. Uncrichie...

[dseman]

Well, it's been a while since I've had to think about this....but I'm sure a sparky will correct me if I need it.

KVA is the apparent power as previously described. It accounts for the reactive power due to inductors and capacitors in addition to the resistive power. The reactive component is actually not used by the welder to accomplish any real work. It is sourced from the power grid to the welder and then back from the welder to the power grid every 1/4 cycle (I think). The size of all the distribution equipment between the power grid and the welder must be sized to account for this amount of current. KW is the real power and is (volts x rms amps x cos (theta)), which accounts for the difference in phase angle between the volts and amps. That means it is a true measure of what the welder actually uses to perform the real work. If you are a homeowner, the power meter outside measures and charges you for the KW and not the KVA--which is a good thing. The power factor is the ratio of KW / KVA. Power companies don't like power factors < 1 because KVA drives the need for larger conductors and distribution equipment. Large loads such as commercial accounts have a KVA power meter and get charged a higher rate, so as to motivate the company to reduce it's overall power factor. Now, on to the synchro 250 example:

Looking at the spec sheet for 250amp output:

96amp/ 230vac (no PFC) = 22KVA
2.6amp/ 230vac (no PFC)idle = .59KVA
51.1amp/ 230vac (no PFC) = 11.76KW
1.26amp/ 230vac (no PFC)idle = .29KW

71amp/ 230vac (w/ PFC) = 16.3KVA
49.5amp/ 230vac (w/PFC)idle = 11.2KVA
51.3amp/ 230vac (w/PFC) = 11.81KW
8.39amp/ 230vac (w/PFC)idle = 1.93KW

So without PFC, you have to size your cable and breakers for 96amps. The power meter would read 51.1 amps when welding at 250amps and 1.26amps at idle. Now with PFC, you can down size the input cables and breaker to meet a 71 amp requirement. Now here is where it gets interesting. The actual current that you pay for when welding is the same for PFC or non-PFC (again if you are using the welder at home). This is 51.1 amps w/out PFC and 51.3 amps with PFC. At idle you are actually using 8.39amps with PFC whereas without PFC you would only be drawing 1.26amps. In other words, you are paying more to your power company (increased idle current) to use the PFC. They like you because you have reduced the power factor going into the welder, and you are paying them more!

If you had a volt/amp meter which used a hall-effect sensor and a true-rms circuit, you could measure the volts and amps. The product of the two would be VA and it would measure both the useless reactive power being sourced and sunk between the power grid and the welder and the resistive component---but the power meter should only be measuring the KW. If you are a homeowner, the only reason I can see for adding PFC is to reduce the size of the input cable and breaker that the welder would require.

-dseman