From: Jim Pennino
Subject: Re: (Avionics) How can this circuit produce an "inductive surge"?
Date: Thu, 3 Oct 2002 15:46:33 +0000 (UTC)
Organization: Special Solutions, LLC
References: <email@example.com> <firstname.lastname@example.org> <email@example.com> <firstname.lastname@example.org> <3D9A879F.CF98EE43@citlink.net> <email@example.com>
NNTP-Posting-Date: Thu, 3 Oct 2002 15:46:33 +0000 (UTC)
User-Agent: tin/1.4.5-20010409 ("One More Nightmare") (UNIX) (SunOS/5.9 (sun4u))
In rec.aviation.owning Tarver Engineering wrote:
> "Jim Pennino" wrote in message
>> In rec.aviation.owning Peter Gottlieb wrote:
>> > "Richard VanHouten" wrote in message
>> > news:3D9A879F.CF98EE43@citlink.net...
>> >> >
>> >> > Why would you run a static inverter to make one frequency of AC then
>> > a
>> >> > MG set to convert to another frequency? Seems like a real kludge
>> > me,
>> >> > 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
>> >> 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
>> > 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
>> > than those required for 60 Hz, and the higher frequency makes other
>> > practical (eg, resonant).
>> Even if you couldn't find a 400 Hz UPS (there are lots of sources for
>> 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!!
> For the same reason we use 400 cycle in aircraft.
The reason being the magnetics are smaller and lighter; the "rectifiers" are
unaffected by frequency.
Got a technical response to that or another ad hominem?
> I think Jimmy needs a nappy poo.