Re: Fadal 3 ph...

The Pre-Meltdown Kid wrote:

Apropos of the recent thread addressing the wild leg on controls, does this also apply to machines with a 3 ph input transformer?
iow, does it matter where the wild leg goes on this transformer? And if so, is it evident where the controls tap off, on the load side of the transformer?
Or do the controls bypass this transformer altogether?

I could experiment, and disconnect one leg at a time, and see what goes on/off with what leg, but I would hate to phuckup the machine... again...

Print/schematic time??

Yes. It would be best to KNOW what is running off which phases.
And, if you have a REAL wild-leg, you may not want to connect it to a phase converter until that is tamed. If a motor gets a momentary excursion to 250 V, it may do no damage. If the control system gets hit with 250 V, the smoke may fly. If the controls run off 230 V single phase, it may be best to pull that out completely, and power it from a separate feed, bypassing the phase converter completely.

There's no way to say on any particular machine, they all do it differently, and in many cases the way it is wired depends on how the machine was ordered (specific to country and voltage settings).

Many larger machines run 3-phase, often at some reduced voltage, to the servo drives, through a big 3-phase transformer. This will usually be a different transformer than the one powering the computer, logic interface, etc.