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From: rf@wu1.UUCP
Newsgroups: net.micro
Subject: Re: Voltage protection for micros (dynamotors)
Message-ID: <356@wu1.UUCP>
Date: Thu, 14-Feb-85 16:43:10 EST
Article-I.D.: wu1.356
Posted: Thu Feb 14 16:43:10 1985
Date-Received: Sun, 17-Feb-85 06:22:43 EST
References: <8159@brl-tgr.ARPA>, <5391@duke.UUCP>
Organization: Western Union Telegraph, Mahwah, NJ
Lines: 23

Charlie Martin (mcnc!duke!crm) writes:

  There is a way to do an uninterupptible power supply that will work for
  short periods that I have always wanted to try, but never had the
  need/ambition...

  what you would do is find the cheapest 110/60 alternator you could, and a
  cheap electric motor, and build a GREAT BIG HEAVY mucking flywheel; drive
  the flywheel with the motor, then drive the alternator with the flywheel.

This is the oldest uninterruptible power supply.  It is known as a
"dynamotor" or "motor-generator set".  They work well, but are expensive
and, well, mechanical.  These days they are mainly used in places with HUGE
power requirements which require AC power and can't afford any power
outages; big computer centers, mainly.

Usually, dynamotors are built with diesel engines connected to their common
shaft via clutches.  When power fails, the energy stored in the flywheel can
be used to start the engine & there is not even a change in the phase of the
output current.

				Randolph Fritz
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