From: Pearson Shane <Shane.Pearson@tafensw.edu.au>
Date: Sun, 22 Mar 1998 15:32:31 -0800 (PST)
To: "'StanSquncr'" <cypherpunks@toad.com
Subject: RE: UPSs
Message-ID: <ED111D55D096D111A1990000F8794AF506E287@itfexch3.isd.tafensw.EDU.AU>
MIME-Version: 1.0
Content-Type: text/plain


Hi Stan,

Yeah.

Since the big powersupply transformer primary winding
is in _parallel_ with the AC power coming from the wall,
this inductor will transfer the spikes, etc to the
secondary winding and into the bridge rectifier, etc quite
nicely. But decent ripple prevention should also help out
here. Though this hasn't much to do with PC switchmode
powersupplies.

An inductor/capacitor spike filter that may be in UPS'
would have 2 large inductors in _series_ with the active
and neutral and high voltage capacitors in parallel with
both ends of the inductors across the active and neutral.
This is specifically designed as a low pass filter for
getting rid of spikes.

I don't think the SW supply would do it quite as well with
as much power handling, strength etc. I'd rather a great
big low pass filter designed for spike dampening doing the
deed than having my PC power supply bearing the brunt of it.

It's also an extra layer that is quite cheap.

Bye for now.

> -----Original Message-----
> From:	StanSquncr [SMTP:StanSquncr@aol.com]
> Sent:	Saturday, March 21, 1998 8:51 AM
> To:	Pearson Shane; spectre@anthrax.net; cypherpunks@toad.com
> Subject:	Re: UPSs
> 
> In a message dated 98-03-19 18:48:51 EST, Shane.Pearson@tafensw.edu.au
> writes:
> 
> << A simple low pass filter made of 2 large inductors and a
>  few high voltage capacitors will do the trick nicely. >>
> 
> Right.  The filtering that's already in the power-supply (except that
> the
> switching transformer isn't as big as an inductor as a normal
> old-style power
> transformer.
> 
> Stan