by "Iain Churches" <IainNG@[EMAIL PROTECTED]
>
Apr 22, 2008 at 05:14 PM
"Eeyore" <rabbitsfriendsandrelations@[EMAIL PROTECTED]
> wrote in message
news:480DEDB4.F0493DBC@[EMAIL PROTECTED]
>
>
> Iain Churches wrote:
>
>> "Eeyore" <rabbitsfriendsandrelations@[EMAIL PROTECTED]
> wrote
>> > Iain Churches wrote:
>> >
>> >> The standard 6V3 winding would give 8.8V DC.
>> >
>> > Not with rectifier voltage drops it won't. More like 6.8V.
>>
>> I did not include the rectifier losses.
>>
>> The AC is at about 235V here this afternoon. I have a
>> Welter mains transformer on the bench in front
>> of me. The heater winding is 6.3V at 3A reg 5%. With
>> a BR156 rectifier and 10 000µF and drawing 3A I measure
>> 7.6V across the electrolytic.
>
> With how much ripple ?
<2A ripple. The heater supply is CRC with a WW pot.
C1 is actually 22 000 µF, and C2 is 10 000µF
>
> Drawing 3A DC from a winding designed for 3A AC is likely to burn it out
> btw.
It was designed for a 3A DC heater supply. The AC winding can supply 4.3A
and is intended for a pair of EL34s. I wanted to test the regulation. In
the
couple of mins it was drawing 3A DC it got only warm. The heaters draw
some five or six times their rated current when cold at switch on.
>> What does a SS regulator require?
>
> If you use a 'low dropout' type you may need as little as 0.5V of
> 'overhead'.
OK. That's interesting. Care to continue with a new thread?
Iain
