David, My feeling is that the Ducati RR is under-designed for its task
and it is really a matter of where you site it under the cowl, that
decides it's fate. By good planning or just good luck, yours seems to
cool well and thus survives. If the Silent Hektik website is to be
believed (see below), the Ducati RR is being over-driven.
Nigel
/*The Ducati controller*//
//The original controller supplied by Ducati Energia is equipped with
semiconductors , which allow a brief loading of 25A at 14V .
Continuous loading of the semiconductor is limited under standard
conditions at 25 C to around 17A. but since the alternator can deliver
up to 20A, the original controller is overloaded even under optimal
conditions. This results in frequent failures. /
On 21/01/2014 22:15, David Joyce wrote:
> <davidjoyce@doctors.org.uk>
>
> 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
>>>>
>>>
>> ===========
>> ===========
>> ===========
>> ===========
>>>
>>>
>>>
>>>
>
>
|