[Amps] AL-800H transformer

[Carl]

----- Original Message ----- 
From: "Manfred Mornhinweg" <manfred at ludens.cl>
To: <amps at contesting.com>
Sent: Sunday, October 13, 2013 3:09 PM
Subject: Re: [Amps] AL-800H transformer


> 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


With much lower core loss and less than half the primary power and half the 
secondary power consumed the regulation should be much better than the 15% 
Ameritron rates it at in the 811H.

In intermittent duty at half voltage you should be able to pull a bit more 
current at that 15% regulation but temperature rise should be measured 
first.

Carl
KM1H