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Re: Europa-List: electrics

Subject: Re: Europa-List: electrics
From: n3eu@comcast.net
Date: Thu, 1 Jan 2004 22:06:46

Gilles.Thesee wrote:
> 
> Fred,
> 
> Would you mind sharing with us the regulator schematics you have ?

I have only the one, plus the internal photos, which you shared with me; nothing
independent of that.  

> We've been conducting some investigation into the Rotax regulators, and they
> appear to be far from cleverly engineered. 

[Nerdy tech stuff follows]

By clever I meant it's an SCR shunt regulator, but they don't use a bridge 
rectifier,
which is not fail-safe because the ground return is hard-wired.  But here
each SCR alternately provides its sibling's ground reference during the period
it is letting a half-cycle of AC pass. If one SCR opens or shorts, output
will be seriously reduced.  Another failure mode is ground reference totally 
severed,
so B+ just floats in space, effectively zero output.

However, your engineer friend may be better at this stuff, with less chance of
being wrong!

> Even at 10 A, half the advertised 20 A rating, the unit gets notably
> hot.

Is is cooler at around 15A?  A shunt regulator can be and if so, a good excuse
for more avionics? 

Reg,
Fred F.




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