"daestrom" writes:


wrote in message
...

What about multiple parallel transformers, or at least multiple parallel
windings on the same core (on whichever side the tapping is to be done),
where the taps are stepped incrementally on each winding? Instead of a
shorted winding segment, you'd have windings of differing voltage in
parallel as each of the windings change their taps one at a time.

That's still essentially a shorted turn (or set of turns).

So when one is set for say 118V and the other is set for 120V, you have a
118V source connected in parallel with a 120V source and the only impedance
is the transformer windings??

OUCH!!! I think the magic smoke will be spewing in no time

Phil, did you see daestrom's excellent explanation how they use an
inductor to prevent a dead short but in a way such that the inductor is
virtually not there during normal operation (counterflowing currents)?

If these tap changers are rather expensive, I'm wondering what those
pole pig "voltage regulators" I mentioned are. I thought they were just
tapped autotransformers.