Re: transformer theory q

["Tesla list" <tesla-at-pupman-dot-com>]

Original poster: "Malcolm Watts by way of Terry Fritz <twftesla-at-qwest-dot-net>" <m.j.watts-at-massey.ac.nz>

Hi Pete,
         
On 13 Nov 2001, at 12:39, Tesla list wrote:

> Original poster: "Peter Lawrence by way of Terry Fritz
<twftesla-at-qwest-dot-net>" <Peter.Lawrence-at-Sun-dot-com>
> 
> 
> Tranformer gurus,
>                  I might actually make some progress on my mechanical xfrmr
> winding jig over Thanksgiving holiday, so I have a question about xfrmr
design.
> 
> If I follow the design guide at for example 
> 	http://members.tripod-dot-com/~schematics/xform/xformer1.htm
> I get a certain number of turns in the primary to match the core cross
section
> of the laminated core that I have obtained.
> 
> What if I use fewer turns in the primary to up the turns ratio (I've only got
> so much room for secondary turns in a fixed winding window size).
> 
> What happens with fewer primary turns than "recomended" for a given core.

It depends how many fewer than the recommended number you wind. I've 
done this myself. In my case, a 12% reduction pushed magnetizing 
current from 1A to 6.5A. A consequence is less tolerance to power 
line surges and much higher copper losses in the primary. Not great 
for wallplug efficiency.
 
> thanks,
> Pete Lawrence.
> 
> 
> 
>