alt swit
Jim
thanks
YES - I have to say I was quite alarmed by 70A! Since I was in the air
some way from a suitable place to land I carried on figuring that all I had
heard indicated that the rotax would be hard put to produce a consistent
18A let alone 70A. The sparks and smoke stayed in the wire.
Of course I checked and rechecked everything but could never replicate the
fault on the ground. This suggests that this is something to do with a
warm engine and high power. As a reuslt of this discussion it occurred to
me that the fault might be the voltage regulator showing signs of failing?
Mine is mounted on the engine side of the firewall so heat could be a
factor.
I have a hall effect sensor on the battery wire and this has never
shown major fluctuations.
So yes Im guessing that its a fault in the dynon or my installation or a
loose connection or a bit of all three.
My next item is to check the output of the alt using an
independent instrument.
Will
William Daniell
LONGPORT
+1 786 878 0246
On Fri, May 15, 2020 at 1:52 PM h&jeuropa <butcher43@att.net> wrote:
>
> Will,
>
> As Gilles pointed out above, the weak point of the Rotax system is the
> Ducatti rectifier/regulator. The electrical design is fine, the problem is
> the construction. Early ones, P/N 343620, had diodes that unsoldered
> internally. There is an easy work around for this (2 external diodes).
> Later ones, P/N 362001, are poorly manufactured with cold solder joints,
> unsoldered joints and mechanical failures. Either one seems to work pretty
> well if the load is kept low, certainly less than 10 amps and best if
> closer to 5 amps.
>
> Silent Hektik regulators, made in Germany have been used by many Rotax
> owners. They are difficult to purchase in the US, although they may be
> available from Vans Aircraft as an alternate on the RV12.
>
> Some owners have purchased John Deere garden tractor regulators and used
> them with success. Part number AM101406 is usually the one mentioned.
>
> B&C Speciality has just developed a replacement for Ducatti, the part
> number is AVC1. You can find an install manual on their website but it's
> not yet listed for sale.
>
> I built a Mike Miller replacement. Mike is an electrical engineer with a
> RV12. Ducatti failures are pretty common in them. He inspected many
> failed Ducatti units and summarized the problems as stated above. He
> designed a replacement that is electrically identical but has more robust
> components and most importantly larger heat sink. His will operate at 20
> amps all day!
>
> Our Europa draws about 8 amps in flight. We used an early Ducatti with
> external diodes for many years. At some point we purchased the later model
> Ducatti and used that for a couple years. Finally a year ago I built the
> MM replacement and have had no problems.
>
> I hope this offers some insight and maybe solutions. Your 70A spike
> sounds like an instrumentation problem, but other than temporarily
> installing a second ammeter, I don't have a solution in mind.
>
> Jim Butcher
>
>
> Read this topic online here:
>
> http://forums.matronics.com/viewtopic.php?p=496382#496382
>
>
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