From: "Tarver Engineering"
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Subject: Re: (Avionics) How can this circuit produce an "inductive surge"?
Date: Thu, 3 Oct 2002 07:57:56 -0700
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"Peter Gottlieb" wrote in message
> "Richard VanHouten" wrote in message
> > >
> > > Why would you run a static inverter to make one frequency of AC then
> > > 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
> 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).
The motor generator set was there before there was an UPS to connect to it.
Then there was a 60 cycle UPS.
Then there came the 400 cycle 2N2222 UPS.