View Full Version : Syncrowave 250DX - Amp supply question?
07-06-2006, 07:45 PM
I am thinking about buying a Miller Syncrowave 250 w/power factor correction. In my home machine shop, I have a 230v, 50amp, single phase rec that I have used for buzz-box welding. I don't want to wire higher amp power for this Syncrowave 250... as I will build another home in the next few years and will provide correct power at that time.
My question... how far can I push this Syncrowave 250 on 50 amps? I will use a gas cooled torch for now, and so will not use the torch "water cooler" for now (lower runtime power requirements). My initial weldments will be mostly 1/8-3/16" steel... maybe some 1/8-3/16 aluminum. Can I weld this material on a 50amp service? If not, what could I weld before the breaker trips?
Thanks in advance,
07-06-2006, 08:16 PM
Since you don't mention that you ran the welder receptacle yourself, verify that you have at least #8 wiring to that 50A welder receptacle. Buzz boxes, because of their much smaller duty cycles, can use smaller wire and still have a 50A breaker.
I'll check out the machine's specs for the rest of the question.
The Syncrowave 250DX with power factor correction draws 49.5 amps at idle. At 200 amps output it draws 52 amps and at 250 amps output it draws 71 amps. A 50 amp circuit MAY allow the machine to operate at under 200 amps output but you are right at the limits. As Mac pointed out the wiring has to be able to sustain a near 50 amp continuous load. I suspect that you would get circuit breaker trips.
Looking at the manual further, it states that the welder draws 72 amps at rated output. Miller recommends a minimum 8 guage wire and an 80 amp time delay fuse ( or comparable breaker ). If in fact the wire to the receptacle is at least 8 guage you may be able to hard wire in the welder to the receptacle box and make it a dedicated welder circuit. This would allow you to put in a larger breaker. Of course, when you move you should put the 50 amp breaker and receptacle back in.
07-08-2006, 06:31 PM
Ron and Mac,
Thanks for your reply.
I wired my shop from a 100amp secondary service panel installed when I had my current house built. A year or two later, I built my basement shop with a building permit, etc. I did all of the wiring and that wiring was inspected by my city's electrical inspectors. More than just my shop is on this 100 amp panel.
For my "Welding outlet", I used #6 copper (AWG 6 CU 3 CDR with AWG 10 Ground Type NM-B) with a 50 amp breaker. The welding outlet is about 6 feet from the service panel. I used #6 because at that time, the tables I looked at (in Home Depot, Lowes, etc.) rated AWG #6 as 55 amps. Anyway, maybe I lucked out here.
So with this #6 wire, I guess I can deduct from your comments that I will be okay driving the Syncrowave 250 on this circuit providing that I change the breaker to some form of a "slow blow" breaker? (And for the next home owner, I will put back the 50amp breaker.) Is there such a thing as a "slow blow" breaker? What ampacity breaker (not a fuse) would you use here?
One final question regarding power factor correction... I did see in the Miller documentation that power factor lowers the overall power consumption. My question, how can the Syncrowave 250 still consume 49.5 amps at idle? If you are not welding, where on earth is all of the energy going? I hope not up as simple heat within the power supply... yikes.
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