--- Apptech <apptech@paradise.net.nz> wrote:

> > I have quite a few dead stuff thanks to faulty
> > transformers. Do anyone have any guides on
> repairing
> > transformers the practical way? One of the
> > main problems is that I do not know how much to
> wind
> > on the transformer..... The voltage values are not
> > printed on the transformer itself*can't work back
> on
> > paper*.......
> 
> Turns per volt will vary with core size (amongst
> other 
> things, and will generally decrease with increasing
> size).
> 
> If you have a dead secondary that can be stripped
> off, and 
> the primary is OK then it is easy to find the turns
> per 
> volt. Simply wind on a known number of turns and
> then 
> measure the voltage. eg if 20 turns gives you 3.7
> volt then 
> TPV = 20/3.7 =~ 5.4 tpv.
> 
> Winding primaries is potentially (pun almost not
> intended) 
> more demanding and you probably want to 'serve your
> time' 
> learning with lower voltage secondaries first.
> 
> Be aware that some types of transformer have
> specialist 
> cores with partial magnetic shunts and/or
> arrangements to 
> give non linear saturation. Examples may be found in
> 
> microwave ovens and in ferro-resonant regulators.
> 
> 
>         Russell
> 
> -- 


Thanks Russell. I was not aware of specialist cores.
For those types I use am going to call for a
replacement.

Thanks,
John Chung.


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