Jan,
As the originator of this thread a week or so ago I was very interested to
read the input from 'Arrow'. Whilst the German translation needed some
translating I got the drift and understand what seems to be happening. My
regulator started to show signs of 'switching off' after I had flown a
couple of long sectors in high heat to Scandinavia. (3 + hours at a time and
chasing a faster aircraft (another Europa - monowheel)). The warning light
did not come on but the volts started to degrade and then the voltage would
be back up to 13+ without warning.
What concerns me is that Rotax are aware of the problem but (apparently)
have done nothing about it!? I purchased a new regulator from the Rotax UK
dealers (Skydrive) this last weekend without any warning of the problem
re-occurring.
Other Europa owners have warned me of the problem and suggested the Schicke
alternative.
Thanks again and we will see if there is any further news from Rotax in due
course.
Regards
Steve Pitt
G-SMDH Trigear XS 912S
----- Original Message -----
From: "Jan de Jong" <jan.de.jong@xs4all.nl>
Sent: Friday, August 08, 2008 11:20 AM
Subject: Re: Europa-List: Ducatti Rectifier/Regulator
>
> Hi Jos,
>
> I think I found an interesting bit of forum:
> http://www.pilots24.com/pilots24/forum/viewtopic.php?t=7756&sid=542ce097cbdde3a5ceba2e5bd0d71c38
> Scroll down to 40% of the page.
>
> Writer Arrow is convinced that he has found the problem with the
> 912/Ducati regulators, as follows.
> The regulating bridge has 4 elements:
> 2 power diodes MR2510 and 2 thyristors TP154E (obsolete) or 2N6504.
> One diode and one thyristor in series conduct part of one half sinus of
> the alternator output, the other diode and other thyristor in series
> conduct part of the other half sinus of the alternator output.
> The thyristors have TO220AB packaging and are mounted directly to the
> housing.
> The diodes have MICRODE BUTTON CASE 193 leadless packaging and Ducati
> designed a mounting technique: both diodes with their cathodes soldered to
> a small copper sheet, copper sheet mounted to the housing using silicone
> foil heat conducting isolation; wires to the PCB soldered to both anodes
> and the copper sheet.
> Everything potted with a potting compound.
> The problem is that heating/cooling cycles work the electrical connections
> to the diodes loose. The symptoms are as follows: charging ok after
> startup (13.8V), losing it after half an hour, but the warning light stays
> off.
>
> The writer has a diagnostic test using a battery and two 12V lamps to
> check continuity under heating.
>
> The writer has a solution: parallelling the diodes with an external pair.
>
> The writer has notified Rotax and asked them what they had done / were
> doing about the problem (January 2008). The correspondence can be followed
> at:
> http://www.pilots24.com/pilots24/forum/viewtopic.php?p=48297&highlight=#48297
> Scroll 30% down.
> The upshot seems to be that Rotax knows there is a problem but it must be
> because units are operated above 80C. No redesign yet.
>
> By the way, Jos, the MR2510 datasheet shows a forward voltage drop of 0.9
> to 1.0V at 20A, the 2N6504 one of 1.3V at 20A. Your 0.6V is too
> optimistic! Newer parts may be better...
>
> I understand that Schicke and Silent-Hektik make a better product than
> Ducati:
> http://www.schicke-electronic.de/dgr3.htm
> http://www.silent-hektik.com/Duc_R_Duc.htm
>
>
>
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