Re: A CW TC without a tube + Re: Solid state TC progress ?

To: tesla-at-pupman-dot-com
Subject: Re: A CW TC without a tube + Re: Solid state TC progress ?
From: "Malcolm Watts" <MALCOLM-at-directorate.wnp.ac.nz> (by way of Terry Fritz <twftesla-at-uswest-dot-net>)
Date: Sun, 09 May 1999 22:46:12 -0600
Approved: twftesla-at-uswest-dot-net
Delivered-To: fixup-tesla-at-pupman-dot-com-at-fixme

Hi Marco,

> Original Poster: "Marco Denicolai" <Marco.Denicolai-at-tellabs.fi> 
> 
> Hi Malcolm.
> 
> A few more info about that toroid story.
> 
> The toroid and its windings were simulating the transformer primary. In
my SMPS
> topology it receives pulses of opposite polarity so there is no DC and
> degaussing is ensured. Its permeability was 90.

Exactly. The core was subjected to large flux swings.
 
> What I couldn't find from the Philips databook (it was a Philips part)
were the
> high-frequency losses figures: good to hear from you that they have got high
> ones.
> 
> I received today a sample of a Siemens U93/76/30 core (U-U couple): that
is the
> biggest from Siemens! The problem is that the material is N27, which has
> reasonable losses up to 25 kHz (I use 50 kHz). Boy, that has got a Ve of
297000
> mm3 and an Ae of 840 mm2! Great size but not optimal material...

N27 is a great choice for your application IMO. (Philips equiv. 3C85)

> Therefore I'll stick with the Philips parts (U100/57/25) and wait to receive
> their U-core samples (otherwise I should make new bobbins with a different
> size).
> 
> During the past week I have spent my time reducing noise and ground
glitches on
> the SMPS controller (from 300 mV to 20 mV): still, a PCB would be the best
> solution, expecially a 2-layer one.

:)
Malcolm