"David Lesher" wrote in message
news
"Jim Wilkins" writes:


AC line filters reduce higher harmonics but have little effect at
the
fundamental frequency. The components simply aren't big enough to
store much energy and return it later.

Ferroresonant transformers are 60 Hz sine wave filters with voltage
regulation, but look at the weight:
http://www.hammondmfg.com/CVR.htm

And their output voltage is a function of frequency; so when the
generator speed varies. It's also difficult to design F-R tanks
to deliver sine wave output.

They flatten the peaks as the core saturates, which isn't that bad.
The rise and fall is still close to a sine.
-jsw