Скачать или смотреть Convert a 240v arc welder into a 415v PSU

Many arc welders at the higher end of the power scale (for domestic/hobby use at least) are capable of being run on two different power supply voltages. Many of these can be converted so that the higher voltage is available as an output instead of an input, whilst still keeping the normal welding capability.

Here's how I did mine.

It's not a three-phase output though, the 230-240v and 170-175v outputs are 180° out of phase to give 400-415v between them.

If used in conjunction with a 0-270v variac you can produce a 0-467v variable output, albeit with a lower output current (approx. 5.7 amps for every 10 amps of variac rating, factor in transformer losses and you may as well just halve the variac rating).

Two supply configurations are available:-
If the input L1 pin is Neutral and L2 is 240v, the output switch pins are 1: Neutral, 2: 415v, 3: 240v.
If the input L2 pin is Neutral and L1 is 240v, the output switch pins are: 1: 240v, 2: 170v (opposite phase), 3: Neutral. Voltage between 1 and 2 is 415v.

WARNING
A device designed for 240 volts will try to draw much more power on a 415 volt supply. For example a 100 watt bulb fed with √3 x voltage will draw √3 x current (as the filament's resistance is the same) and therefore draw 300 watts. You may expect a bang but end up with a boom, so be careful!