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From: larry@kitty.UUCP (Larry Lippman)
Newsgroups: sci.electronics
Subject: Re: UPS's that aren't
Message-ID: <1932@kitty.UUCP>
Date: Wed, 12-Aug-87 09:22:33 EDT
Article-I.D.: kitty.1932
Posted: Wed Aug 12 09:22:33 1987
Date-Received: Sat, 15-Aug-87 04:43:38 EDT
References: <161@tmsoft.UUCP> <1924@kitty.UUCP> <654@neoucom.UUCP>
Organization: Recognition Research Corp., Clarence, NY
Lines: 30
Summary: Interesting type of UPS...

In article <654@neoucom.UUCP>, wtm@neoucom.UUCP (Bill Mayhew) writes:
> In our case, the administrator opted for a motor/generator type
> UPS.  The motor/generator takes advantage of the intertia of the
> mot-gen armature to keep power going while the switch over from
> mains power to batteries takes place.  There is also never any
> glitch on the load since it is always connected to the generator

	I once saw an interesting variety of a UPS that was installed
in a remote pipeline pumping station to maintain control power and
emergency lighting.
	This UPS consisted of an AC motor operated from the line, an
AC generator which powered the load, a large enclosed flywheel, all
of which was connected to a 4-cylinder propane-fueled engine.  The
engine turned over continuously with the AC motor and generator, but
was not running since the ignition and fuel were turned off.
	When power failed, the ignition and fuel were turned on, and
the engine would start and be up to load within a cycle time since
it was already running at governor speed.  The flywheel provided
sufficient inertia that only negligible degredation of output power
occured during the power loss transition.
	This UPS was only rated at about 7 kva.  It was an OLD system
dating from the 1950's, and I believe it was made by Bosch (but I
could be mistaken).  I have never seen another UPS of this type anywhere
else, and I rather suspect that few were sold due to the continual
mechanical wear on the engine.

<>  Larry Lippman @ Recognition Research Corp., Clarence, New York
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