Tim, I absolutely accept that it is not ideal and could
cause more serious problems than simple lack of charge,
but one benign failure in 12 years of flying is pretty
close to acceptable reliability for me, and I enjoy
gliding anyway!
Happy Landings, David
houlihan <houlihan@blueyonder.co.uk> wrote:
> Hi David.
>
> One thing to bear in mind is that there are, as I
>understand it, several
> modes of failure of the Ducatti unit the most benign
>being that it just
> stops charging the battery and feeding the services.
> This is as you describe and as I also suffered ( why
>does this happen mid
> channel?) but I believe it can fail and possibly allow
>high voltage DC or
> AC onto the bus giving your expensive radio and other
>clever stuff a real
> hard time !
>
> In the UK there is very little difference in cost
>between the Schicke and
> the Ducatti they are very similar in size and the
>wiring is only slightly
> changed , one wire not connected, and the generator fail
>light has to
> become an LED.
>
> Tim
>
>
>
> On 21 January 2014 19:13, David Joyce
><davidjoyce@doctors.org.uk> wrote:
>
>> davidjoyce@doctors.org.uk>
>>
>>
>> Nigel, Fascinating and impressively erudite. You have
>>totally convinced me
>> that the way all new builders should go is with a Mofset
>>bit of kit.
>> However my personal solution is to take the odd Ducatti
>>at sale price off
>> anyone not planning to fit them and fly with a spare! In
>>1000hrs I have had
>> one failure. That was inconveniently 1/3 way between
>>Holland and Clacton,
>> but there was enough juice in the battery to get me all
>>the way home with a
>> bit of thoughtful systems management. I currently fly
>>with Rowland's
>> spurned new Ducatti in my spares department under pax
>>seat, but am prepared
>> to offer a modest price for another unwanted Ducatti!
>> Regards, David
>>
>> "nigel_graham@m-tecque.co.uk"
>><nigel_graham@m-tecque.co.uk> wrote:
>>
>>>
>>> I have followed this discussion with great interest and
>>>with an
>>> increasing sense of Dj vu.
>>> When the issue of regulator/rectifier failures occur
>>>withing the Rotax
>>> community, the standard fix seems to be to simply
>>>replace like with like
>>> (at elevated Rotax pricing) and fly on until the next
>>>unit fails.
>>>
>>> Up until about five years ago, nearly all modern
>>>Japanese motorcycles
>>> used the same technology as that found on the Rotax 91x
>>>series engines,
>>> permanent-magnet generators controlled by SCR
>>>rectifier/regulators. It may
>>> come as some surprise that for an industry renowned for
>>>precision and
>>> reliability, nearly all of these major motorcycle
>>>manufactures have at some
>>> time, been plagued by problems with their SCR based
>>>rectifier/regulators
>>> failing and burning out alternators and wiring, cooking
>>>batteries and in
>>> extreme cases, squirting unregulated AC into the wiring
>>>loom and blowing up
>>> ECUs. It was just such a failure that "sparked" my
>>>interest :-(
>>>
>>> Known as "Shunt Regulators" the SCR technology runs
>>>extremely hot and
>>> requires more cooling air than modern styling and space
>>>allows.
>>> The solution was a move towards MOSFET controlled
>>>regulators and the
>>> numerous web-based one-make discussion groups were full
>>>of information and
>>> advice on the reasons for failure, the benefits of the
>>>change and practical
>>> advice on how to convert.
>>>
>>> It was by trawling these groups that I was able to build
>>>up a good
>>> understanding of how these R/Rs worked, what was causing
>>>the problem and
>>> what the potential solution might be. I compiled what I
>>>considered to be
>>> the best informed snippets of information into the
>>>attached document.
>>> The first half gives an overview of a typical design of
>>>an SCR
>>> Rectifier/Regulator for use on a permanent-magnet
>>>generating system and the
>>> second half discussed the relative merrits of SCR versus
>>>MOSFET.
>>>
>>> It would be interesting to know which technology the the
>>>after-market
>>> Schicker and Silent-Hektic R/Rs use.
>>>
>>> Nigel
>>>
>>
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