Re: Removing impedance protection from MOEPED #3

From: Dimitrios Tzortzakakis (dimtzortihatespam_at_nospamotenet.gr)
Date: 12/21/04 

Date: Tue, 21 Dec 2004 16:13:39 +0200



--
Tzortzakakis Dimitriïs
major in electrical engineering, freelance electrician
FH von Iraklion-Kreta, freiberuflicher Elektriker
dimtzort AT otenet DOT gr
Ï "daestrom" <daestrom@NO_SPAM_HEREtwcny.rr.com> Ýãñáøå óôï ìÞíõìá
news:ZwCxd.77909$AL5.43375@twister.nyroc.rr.com...
>
> "Dimitrios Tzortzakakis" <dimtzortihatespam@nospamotenet.gr> wrote in
> message news:cq6i46$eo2$1@usenet.otenet.gr...
> Sorry, but you are wrong.  Asynchronous induction motors can be used as
> generators.  They have to be driven at a speed higher than the synchronous
> speed.  The winding must be excited from an external source of reactive
> current (the utility line or capacitor bank will do).  They are much
harder
> to regulate/control than synchronous when in an isolated 'island'.  But
when
> connected to a grid they can work quite well.
That's what the theory says anyway.But here we have many problems from these
"wind generators" coupled to the grid;lights "flickering";grid
instability;many power outages.
>
> And a DC motor can often be used as a DC generator as well.  In fact, many
> large un-interruptible power systems use DC machines that act as
generators
> to charge/float station batteries normally, yet can instantly change roles
> to act as motors to drive the AC generator from the batter when the normal
> power is lost.
>
Yes, of course but they don't have such great efficiency when working on the
opposite role.A generator has the best efficiency when used as a generator,
and a motor when used as a motor.
> daestrom
>
>

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