Hello Paul
To answer your 2 questions:
1) See page #4 of the Europa Club Over-voltage Crowbar Unit Installation.
Figure #2 is for Permanent Magnet which is what you want. The OV crowbar
mod does not take the place of the alternator output switch. It essential
puts a relay in series before the 30 amp slow blow fuse. If over-voltage
is detected, the crowbar unit will crowbar (create a short) placed on the
5 amp circuit breaker and pop and take the Rotax Alternator (really a
generator) off line.
I chose to use Eric Jones solid state OV protection on my Rotax generator:
http://www.periheliondesign.com./lovm.htm
2) I don't absolute agree with Gilles, if wired as per Europa, if for any
reason battery is not putting out, 1 pump will run off of generator
(provided it is excited, which would have happened upon start up), that is
why there is no switch to turn it off?? If generator fails, you can run
the other pump off of battery. As far as turning off fuel flow in event of
emergency, turn off the fuel selector (not good practice to run a pump dry
if you can avoid).
Gilles has 2 batteries on his 914 install which in my opinion is better
than Europas redundancy. That said I think if you are only going to have 1
battery and only internal generator, following Europa is not such a bad
way to go. I personal would put a switch on pump #1 and some sort of light
or warn to show it is off, that way you can test output of pump #2 more
easily.
I went with on my 914 with a SD20S as primary alternator with LR3C
regulator with built in OVP and Rotax internal generator as second or
standby with Eric's solid state OVP. Schematic loose based on Bobs Z13 /
8. 1 pump main bus and 1 on endurance bus. I also have a total loss 13
cell 2200mA NiMh battery pack in the starboard headrest, in under 10
seconds can run a pump on it (redundant wires to this connector), or if
lost main battery and main alternator, can excite internal rotax, or run
endurance bus from it. Very light, yet can probably output enough to start
the 914! Model guys draw 150 amps plus from these cells. When soaring,
and main battery fails open upon restart, in 10 seconds and can run prop
off this battery to air-start after I take main alternator off line, if no
time to cycle prop and not enough altitude to dive can probably restart
form it, then put rotax internal on line (Rotax is much happier than SD20S
ND with no battery.
More than you asked for.
Ron Parigoris
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