[Amps] AL-800H transformer

[Manfred Mornhinweg]

Hi Paul,

> I was thinking I could wire the primary as 250VAC input i.e. put all
> primary windings in series and supply it with 110VAC input which
> should drop the HV output to less than half.
> 
> What doe the experts on here say?


It's right - when you apply half the input voltage, you get half the 
output voltage. The magnetic flux in the core will be halved too, so 
that the core will have only about 30% the loss it would have at full 
voltage. But the current handling ability is the same as at full 
voltage. This means that the power output it can produce, at half the 
voltage, is also only half its rating. And the voltage drop at that load 
will be as much as at the full voltage, so that the percentual stability 
of the output voltage under load changes is only half as good as at full 
voltage.

Since you need just 400mA, that transformer should work OK. It can 
hardly have been designed for much less than that current. Just be aware 
of the lower voltage stability, compared to a transformer optimized for 
the voltage you need.

Manfred

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