Rotax 912 ULS Electrical Systems
in 912 / 914 Technical Questions
12 years ago
I am in the process of building a new panel for my Rans S-12S. I was careful to label each wire as I took it off, but found later that some of the labels didn't stick and just fell off. Got the latest copy of the wiring diagram from Rotax, also another simpler one online, and the original plan from back around 1998 when the engine was built. I have a few questions though.
1) Each of those diagrams is different in one way or another. (I am not very experienced in reading these so this may be a problem with my perceptions.)
2) Am I right in thinking that there are a number of different wiring systems that all interconnect when it comes to power and grounding? (ie.: Ignition system, avionics, panel lighting, engine instruments, to name the ones that come to mind)?
3) I've found some differences between my present systems and those in the diagrams. I don't have shielded P leads, but the diagrams show them shielded. I plan on replacing these.
4) I have two alternators and would like to use the external larger one as the Primary instead of the smaller built in one which feeds the battery and systems through the rectifier-regulator. I read an article that suggested adding an on-off-on switch to replace the current circuit breaker switches for each alternator. If I do this I assume I would have to put fuses or circuit breakers into each alternators line. But can I make this change and if so how should this ignition system be wired?
5) I have multiple circuit breakers and fuses (more then the wiring diagrams show). Can some of thse be pulled out. One diagram shows only two 30 amp slow blow fuses in the whole system. The newest shows a 50 A and a 5 A in the external alternator system and a 25 A in the internal system. Currently I have a 60 amp circuit breaker and a 7.5 breaker switch in the internal system, and a 30 amp in the expternal system. The wiring diagram shows a 50 and a 5 in the external system and a 25 in the internal system.
Can you see why I'm having problems with putting things back together. I can either try to put things back together as they were to begin with, or do it "right" according to one of the diagrams. But which one, and especially which fuses/circuit breakers, how many, and where do they go? Also, do I treat the ignition system as a seperate system? If so, where does it connect up behind the panel.
Hope you've held with me through all of this. If so, thanks. I look forward to any suggestions anyone might have to share.
Bill Nelson
1) Each of those diagrams is different in one way or another. (I am not very experienced in reading these so this may be a problem with my perceptions.)
2) Am I right in thinking that there are a number of different wiring systems that all interconnect when it comes to power and grounding? (ie.: Ignition system, avionics, panel lighting, engine instruments, to name the ones that come to mind)?
3) I've found some differences between my present systems and those in the diagrams. I don't have shielded P leads, but the diagrams show them shielded. I plan on replacing these.
4) I have two alternators and would like to use the external larger one as the Primary instead of the smaller built in one which feeds the battery and systems through the rectifier-regulator. I read an article that suggested adding an on-off-on switch to replace the current circuit breaker switches for each alternator. If I do this I assume I would have to put fuses or circuit breakers into each alternators line. But can I make this change and if so how should this ignition system be wired?
5) I have multiple circuit breakers and fuses (more then the wiring diagrams show). Can some of thse be pulled out. One diagram shows only two 30 amp slow blow fuses in the whole system. The newest shows a 50 A and a 5 A in the external alternator system and a 25 A in the internal system. Currently I have a 60 amp circuit breaker and a 7.5 breaker switch in the internal system, and a 30 amp in the expternal system. The wiring diagram shows a 50 and a 5 in the external system and a 25 in the internal system.
Can you see why I'm having problems with putting things back together. I can either try to put things back together as they were to begin with, or do it "right" according to one of the diagrams. But which one, and especially which fuses/circuit breakers, how many, and where do they go? Also, do I treat the ignition system as a seperate system? If so, where does it connect up behind the panel.
Hope you've held with me through all of this. If so, thanks. I look forward to any suggestions anyone might have to share.
Bill Nelson
