220 single phase welder w/120 3 prong house plug?

[Xtreme Off-Road]

If you look at the page again, you will see the transformer diagram. It is just a matter of windind the 2 coils on the secondary side in the opposite directions. Yes this is still a single phase output, but they are 180* out of phase from each other. Commonly refered to as line A and line B.

 

[MR4WD]

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If you look at the page again, you will see the transformer diagram. It is just a matter of windind the 2 coils on the secondary side in the opposite directions. Yes this is still a single phase output, but they are 180* out of phase from each other. Commonly refered to as line A and line B.

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I'm afraid you misunderstand. It's impossible to have anything 180 degrees apart when you apply 3 phase to it. It is however possible, to create a short (and derive power from it) across two seperate windings in the can.

THAT will make you think you have 180 degree phase seperation.

Edit- it's not line A and B, it's X1, X2 X3 and X0, or just X1 and X2.

tim, multiply 120 by (I think) 1.67 and then by two to get the peak voltage of 240. I'll check tomorrow when I'm way more soberer.

 

[84_Chevy_K10]

Um, no. When referring to AC you never quote peak power. If we're talking about 240 volts running into a house, that is RMS, not peak.

 

[justinf]

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It may be 3 phase or single phase, but either way (208-120 or 240-120). You can take two legs from that and have 240.

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Two legs from a 120/208, 3 phase system does not give you 240V, it gives 208, because the phases are 120* out of phase with one another.

A single phase transformer uses two legs of the primary line. The coil is wound such that you get 240V across the coil, then the coil is center grounded, this is the neutral that runs into your house.

The two phases in a typical house are 180* out of phase, because of grounding the center. If you plot the waveforms, they have to be in order for the voltage to be 240V. The voltage waveform on both phase conductors is the same, a sine wave, with the same peak values. So, since the voltage between two points is the difference in potential at those points, the phases must be 180* apart. I will double check my points above later today, but off the top of my head, this is what is happening. Transformers do cause phase shifting which will cause the two primary phases which are 120* apart to shift to 180* apart.

Like I said, I will double check my points and post up later. /forums/images/graemlins/thinking.gif

 

[84_Chevy_K10]

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Two legs from a 120/208, 3 phase system does not give you 240V, it gives 208, because the phases are 120* out of phase with one another.

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Thank you. /forums/images/graemlins/bow.gif