On Sunday, 10 December 2017 08:48:23 UTC, GS wrote:
wrote:

I reaad on some website where someone took two 120 to 240 volt
transformers, connected both 240 windings together and ended up with 120
on the secondary, completely isolated from the AC line. This makes
sense, for someone who has two such transformers on hand. But would not
make sense to buy two transformers.

There was an old patent using two neon sign type transformers back to back.

I can't imagine how that could be worth patenting. Many patents have no value.

The problem with isos, you get higher voltage with no load than normal, and
droop 10-20% with load..

It would take an unusually tiny transformer to be that badly regulated.


NT