From: Jim Pennino
Subject: Re: (Avionics) How can this circuit produce an "inductive surge"?
Date: Thu, 3 Oct 2002 01:13:29 +0000 (UTC)
Organization: Special Solutions, LLC
References: <firstname.lastname@example.org> <email@example.com> <firstname.lastname@example.org> <email@example.com> <firstname.lastname@example.org> <3D9A879F.CF98EE43@citlink.net>
NNTP-Posting-Date: Thu, 3 Oct 2002 01:13:29 +0000 (UTC)
User-Agent: tin/1.4.5-20010409 ("One More Nightmare") (UNIX) (SunOS/5.9 (sun4u))
In rec.aviation.owning Peter Gottlieb wrote:
> "Richard VanHouten" wrote in message
>> > Why would you run a static inverter to make one frequency of AC then use
>> > MG set to convert to another frequency? Seems like a real kludge to
>> > not to mention, a very noisy setup.
>> Well, if this is the product that my employer (then K/W Controls, Inc.,
>> now Piller, Inc.) marketed, the static inverter was a standby unit, and
>> the MG set ran off of mains except during a power failure. The 2 second
>> ride-through of the MG set was plenty of time for the inverter to kick
>> in, and your battery string would give you several minutes to shut down
>> your computers, or let your diesel generator kick in if you had a
>> premium setup.
>> The frequency would drop a bit during the transfer, but IBM's spec said
>> that was ok, as long as it stayed above (I think) 370 Hz.
> Well, that makes some sense. But running a frequency converting MG set from
> a UPS is not an optimal solution - why not just make the UPS run at the
> target frequency? The magnetics at 400 Hz are much lighter and inexpensive
> than those required for 60 Hz, and the higher frequency makes other designs
> practical (eg, resonant).
Even if you couldn't find a 400 Hz UPS (there are lots of sources for those
today), I would think the cost of converting a 60 Hz UPS would be a lot
less than buying, installing, and running a MG set.
And don't forget, "The output is also at 400 hz which makes the rectifiers
in the computing equipment much smaller." HAR!!
Sorry, I couldn't resist.