On 14 Sep, 12:09, "Bob Eager" wrote:
On Fri, 14 Sep 2007 10:20:05 UTC, wrote:
Explain please

What I said. In the late 1950s our mains was DC at 240 volts.
Transformers don't work on DC. So what was used?

I had a Tri-Ang train set. It used 12 volts DC. I had a little
motor/generator combined (240v motor, 12v generator) in a perforated
metal case, about 12 inches by 6 by 6 (perhaps a little smaller).
Excitement when my dad came home with a small red box and said "We'll be
using this instead from next week". That was a transformer/rectifier box
to use when they changed our mains to AC.

Sorry Bob, wasn't being rude, just wanted to know what a rotary
converter was. Funny thing is whilst it meant nothing yesterday,
before I read you explanation today I thought - Oh, he probably means
a 240V motor driving a 12V gennie :=))

No problem! I think they were more commonly used to generate AC from
DC....

I know my uncle built one once to convert between 240V and 120V.

It was for an electric fence in his Haunted House (he was a showman)
If the local yoof got a bit excited and started thumping the cage that
the exhibits were in, a nice belt of AC used to calm them down :=))