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A few idiots in these groups believe Wind Generator must have PMA (permanent magnet) Motor. - Page 9

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Posted by harry on July 8, 2009, 7:48 pm


Oh, & BTW  The only places you will get DC from is batteries, PV
cells, thermocouples ETC.  There is always ripple on rectified DC from
a rotating electrical machine.  It can be reduced by
"smoothing"  (capacitors in parallel, inductors in series). But in the
end it will still be there.

Posted by daestrom on July 11, 2009, 2:49 pm
harry wrote:


You obviously have no idea what the output of a good multi-kW or DC
generator looks like on an o-scope.  When you have over a hundred bars
on the commutator (and hence over a hundred windings) wired in a nice
lap winding, with brushes that span four or six bars, you'd be
hard-pressed to find ripple.

And smoothing multi-kw DC with capacitors???  Yeah, right....


Posted by harry on July 13, 2009, 7:32 pm


That would be an expensive machine.  Not been made for sixty years I
bet.  The last ones would have beem pilot excitors for power statio
& BTW capacitors come in very large sizes these days. (Google
& wave windings give a smoother output BTW.

Posted by Day Brown on July 9, 2009, 3:24 pm
 My experience with a waterwheel was that it would produce power less
efficiently, but did so over a much wider range of flow.

And when hooked to an auto alternator, didnt produce nearly as much
power as it did with a generator running at the same speed. Maybe the
efficiency of the alternator would be better if the RPM was higher, but
the higher rev ratios cost power also.

Also, while the Alternator would put out higher peak power, it'd over
heat, whereas the generator would run at peak output 24/7. And, if the
belt got loose, the ball bearings in the alternator tore up right quick,
but the sintered brass bushings in the generator took that forever, or
til the belt snapped.

Course, the old generator was not PM; but there's no reason a PM
generator cant be designed with auxillary field windings to kick in if
the RPM is high enuf.

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