Re: Ferrite Cores - Where's the Gap? (fwd)

[Steven Roys <sroys@xxxxxxxx>]

---------- Forwarded message ----------
Date: Wed, 7 Apr 2004 18:27:48 +1200
From: Malcolm Watts <m.j.watts@xxxxxxxxxxxx>
To: High Voltage list <hvlist@xxxxxxxxxx>
Subject: Re: Ferrite Cores - Where's the Gap? (fwd)

On 6 Apr 2004, at 20:38, High Voltage list wrote:

> Original poster: Steven Roys <sroys@xxxxxxxx>
>
>
>
> ---------- Forwarded message ----------
> Date: Tue, 6 Apr 2004 10:09:36 -0600
> From: Gomez Addams <gomez@xxxxxxxxxxxx>
> To: High Voltage list <hvlist@xxxxxxxxxx>
> Subject: Re: Ferrite Cores - Where's the Gap? (fwd)
>
> On Apr 5, 2004, at 10:51 PM, High Voltage list wrote:
>
> > Date: Mon, 5 Apr 2004 18:20:34 +1200
> > From: Malcolm Watts <m.j.watts@xxxxxxxxxxxx>
> [snip]
> >     A flyback supply will always have a gapped core since energy
> > transfer is accomplished by storing energy in the core (an
> > undesirable property in pushpull and bridge topologies) and the core
> > material itself will store very little energy without going into
> > saturation. Despite the undesirable side-effects of gapping in other
> > types of supply, transformers used in forward converters, bridge
> > converters etc. will often also have some core gapping to obviate
> > flux staircasing.
>
> So, to paraphrase the old Wendy's commercials... "where's the gap?"

If the question is serious rather than rhetorical, the answer is: if
there is no gap in the core, the supply it came out of was not a
flyback supply. Are the core ends firmly pushed together with no
spacer material (e.g. paper, card etc.) in between the pole pieces?
If the answer is "yes", then the core isn't gapped.

      HV and EHT supplies are not always flyback supplies. For
instance, many of the so-called flyback supplies built by people in
this circle are actually self-oscillating forward (often pushpull)
converters. Sorry if this sounds like pure pedantry but this is an
engineering forum of sorts and it is helpful to get accurate
descriptions of equipment to facilitate long-distance troubleshooting.

Malcolm