A question was posed on the Home Improvement SE... Can I buy or make an adapter to hook 2 generators together to run a 220 volt welder? Any contribution to this thread (from an electrical engineer) would be appreciated.
Essentially, the goal would be to take two (random phase) sources of 120VAC or 240VAC and combine them with a device to produce 240VAC. I assume that single phase and 60Hz is important; and conserving/combining the power/amperage would be especially important to the function of the welder.
What device(s) would be used to accomplish this (with respect to efficiency and simplicity of design)? A schematic (and maybe a flow chart) would be wonderful. Also, if the answer really is to rectify AC to DC then invert back to AC, would you (ideally) convert 240 or 120 VAC to DC? Also, would an un-transformed, full-wave bridge rectifier produce about 160VDC from 120VAC and 320VDC from 240VAC?
This "project" seems just like tying a generator to a grid (of equal power). I feel like there must be a better way to tie an AC generator to a grid than to rectify and then invert... and I'm thinking that there must be a controller-device that senses the grid-phase and adjusts the phase from an inverter anyway, right? Wouldn't it be more efficient to just use that controller-device (or something to control the phase or timing) to tie AC from a generator to AC from a grid?
Of course the motors could be mechanically synchronized, but in many circumstances that would not be convenient.