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
|