From: "Tarver Engineering"
References: <email@example.com> <firstname.lastname@example.org> <email@example.com> <firstname.lastname@example.org> <3D9A879F.CF98EE43@citlink.net> <email@example.com>
Subject: Re: (Avionics) How can this circuit produce an "inductive surge"?
Date: Thu, 3 Oct 2002 09:19:55 -0700
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"Jim Pennino" wrote in message
> In rec.aviation.owning Tarver Engineering wrote:
> > "Jim Pennino" wrote in message
> > news:firstname.lastname@example.org...
> >> 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
> > use
> >> > a
> >> >> > MG set to convert to another frequency? Seems like a real
> > to
> >> > me,
> >> >> > not to mention, a very noisy setup.
> >> >> >
> >> >> Well, if this is the product that my employer (then K/W Controls,
> >> >> now Piller, Inc.) marketed, the static inverter was a standby unit,
> >> >> 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
> >> >> in, and your battery string would give you several minutes to shut
> >> >> 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
> >> >> that was ok, as long as it stayed above (I think) 370 Hz.
> >> > Well, that makes some sense. But running a frequency converting MG
> > from
> >> > a UPS is not an optimal solution - why not just make the UPS run at
> >> > 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).
> >> Agreed.
> >> 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
> >> 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"
> unaffected by frequency.
Please do a search for information with respect to capacitors as reactive
components and how frequency is a factor.
> Got a technical response to that or another ad hominem?
You don't even have a basic understanding of AC, Jim.
Once we got to three phase, you have been making a fool of yourself.
John P. Tarver, MS/PE