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Flyback Transformer: sleeving question

Started by Enrico September 5, 2011
Hi,

I'm designing a flyback transformer of a 25 W power supply.

The power supply will be UL tested in Europe. The norm that will be
followed is the UL 60950.

The UL safety engineer told that the Hi-Pot test will be carried out
after leaving the power supply in the humid room for 12 hours at 93%
of humidity.

He suggested me to add sleeving to the transformer.

My question is:
on which leads am I supposed to add sleeving?
Primary? Secondary? Auxiliary?

Thanks,
Enrico Migliore
Hi Enrico,

On 9/5/2011 1:33 AM, Enrico wrote:
> I'm designing a flyback transformer of a 25 W power supply. > > The power supply will be UL tested in Europe. The norm that will be > followed is the UL 60950.
Why are you asking this here and not, for example, in s.e.d?
On Sep 5, 5:15=A0pm, Don Y <nowh...@here.com> wrote:
> Hi Enrico, > > On 9/5/2011 1:33 AM, Enrico wrote: > > > I'm designing a flyback transformer of a 25 W power supply. > > > The power supply will be UL tested in Europe. The norm that will be > > followed is the UL 60950. > > Why are you asking this here and not, for example, in s.e.d?
Hmmm, I would think he has better chances here than in SED. He will certainly get more replies there, though :D . Dimiter
On 05/09/2011 18:03, dp wrote:
> On Sep 5, 5:15 pm, Don Y<nowh...@here.com> wrote: >> Hi Enrico, >> >> On 9/5/2011 1:33 AM, Enrico wrote: >> >>> I'm designing a flyback transformer of a 25 W power supply. >> >>> The power supply will be UL tested in Europe. The norm that will be >>> followed is the UL 60950. >> >> Why are you asking this here and not, for example, in s.e.d? > > Hmmm, I would think he has better chances here than in SED. He will > certainly get more replies there, though :D . > > Dimiter
The simple answer is that it's probably cheaper to buy in a psu, or use a wall wart for the job, unless you plan to build thousands. Psu companies design this stuff every day of the week and will be adept at navigating the legislation... Regards, Chris
On Mon, 05 Sep 2011 07:15:44 -0700, Don Y <nowhere@here.com> wrote:

>Hi Enrico, > >On 9/5/2011 1:33 AM, Enrico wrote: >> I'm designing a flyback transformer of a 25 W power supply. >> >> The power supply will be UL tested in Europe. The norm that will be >> followed is the UL 60950. > >Why are you asking this here and not, for example, in s.e.d?
Yes, S.E.D. might be a more applicable group. Beware of what the UL engineer says though... Whatever sleeve he is talking about may not be necessary. They will some times ask you to do things that are not in the UL spec. This might (or might not) be something that helps to pass the test. Just don't assume when it comes to UL that everything is absolutely required. boB
Hi guys,

thank you for your answers

> Yes, S.E.D. =A0might be a more applicable group.
what is S.E.D.? Enrico Migliore
On 6.9.11 10:30 , Enrico wrote:
> Hi guys, > > thank you for your answers > >> Yes, S.E.D. might be a more applicable group. > > what is S.E.D.? > > Enrico Migliore > >
sci.electronic.design -- Tauno Voipio