"Jim Wilkins" writes:


My old Sola constant voltage isolation transformer isn't nearly
big enough to start my fridge's compressor, which draws 12A for
0.3 seconds.

https://public.magnet.fsu.edu/graf/M...Tranformer.pdf
"In general, the Sola constant voltage
regulator must have a capacity nearly equal to the
maximum demand made on it, even for an instant. "

A friend designed the 3-ph sine-wave-out F-R transformers for
Lorain Products' large UPSi [100 KW & up]. He was the only person
I know who really understood *and could explain* how they worked.

That's a good datasheet, and makes important points; no-load
draws 30+% of full load, they are short-circuit proof, etc.

LPC tested their designs with a LARGE motor, as I recall it was
~4 ft in diameter. They'd hook up way-too-small inverter module
to it, and power it up. The motor would sit there, while the
power module put out its rated current (& hummed mightily.)

If you looked carefully, you'd see the motor twitch, and then
rotate a tiny bit. If you waited, you'd see it move a little
more, finally a full inch of travel. Over many minutes, it
would keep going, gaining speed. After 15-20 minutes, the motor
would get up to 1725 RPM. The module had passed.




--
A host is a host from coast to
& no one will talk to a host that's close..........................
Unless the host (that isn't close).........................pob 1433
is busy, hung or dead....................................20915-1433