Anyone install an external alternator on your 912? I'm helping a buddy install one on his 912. The kit came from Australia with zero instructions or drawings. How did you disconnect the internal alternator? Did you wire the new alternator to the old external voltage regulator?
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912 External Alternator Install?
- Thread starter BobRv4
- Start date
The link below will give some info. Page 29-33 have a diagram.
If you intend to remove the spline driven alternator (it has built in regulator) you can reuse the connecting wires.
On the old alternator, the excitation terminal R provides power to the built in regulator.
On the new alternator, the Field terminal gets a regulated current (A) from the new external regulator.
The current (A) going to the Field terminal varies to uphold the set voltage (V).
Good luck
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Consider utilizing both alternators with the original one being a backup to the external one. Set the voltage regulator output of the original alternator 1/2 volt below the setpoint of the new external one. The original internal alternator will not output any power unless the aircraft electrical system voltage drops.
dbhill916
Well Known Member
IIRC, the electrical power from the internal winding is actually a generator with a permanent magnet and does not have a field winding to modulate. (That's why we have a lot of power to dissipate in the external regulator and the resulting lifespan issues with those regulators.) It may make sense to rely on the internal 912 generator as primary with the external unit kicking in at 0.5 V below your regulated output.
(That's my understanding of the 912ULS. The 912iS has a different system. I belive it has two independently wound generators on the same rotor.)
In 2019 I installed a 40 amp alternator on my Kitfox 912ULS to accommodate a fuel injection retrofit. Rotax dynamo (and regulator) power the MAIN fuel pump. 40A powers the main bus.
Works quite well.NORDO Industries LLC
Member
How are you physically connecting the alternator to the motor?
Another forum user connected an aux alternator to the vacuum pad mount behind the gearbox, but this loses the pitot through the nose. The Monkworkz generator likely has clearance to allow keeping the stock pitot, but will likely require fabricating your own mount for it.
Another forum user connected an aux alternator to the vacuum pad mount behind the gearbox, but this loses the pitot through the nose. The Monkworkz generator likely has clearance to allow keeping the stock pitot, but will likely require fabricating your own mount for it.
