Paul,
We are in the process of completing the electrical circuit on our
project. We do have a Rotax 914 engine.
>
> 1. The Rotax engine monitor shows a double pole switch that is
> for disabling the waste gate servo. Why would I want this, has
> anyone fitted this ?
>
According to the Rotax documents the purpose of this switch is to
disconnect the waste gate actuator in case of turbo surge or calculator
troubles.
Virtually every Rotax 914 owner I know of have installed it. Some had
to use it.
> 2. The Europa manual shows a 25 amp switch for between the
> alternator output and the main buss. I intend to install an OVP
> so I don't see the need for an additional switch, am I missing
> something here.
>
An OV protection is to protect fragile devices against OVER VOLTAGE.
But you still need to protect THE WIRES in case of hard fault. That's
why a fuse or breaker is for.
> 3. Last question, what have folks been using for 30 amp slow blow
> fuses. The only thing I have come across is fusible links the Bob
> Nuckles uses which I don't particularly care for.
What particular feature do you dislike in the fusible links ?
>
> My current thinking is an E-Buss feed arrangement with an
> auxiliary battery, but to still feed one fuel pump (914) directly
> from the alternator output as described in the Europa & Rotax manuals.
>
Our project is wired according to Bob Nuckolls' philosophy, with
essential bus and dual battery. One fuel pump runs direct from the main
battery, and the backup pump from the auxilliary battery. The Rotax
rectifier/regulator has a very poor service record, and the Rotax
suggestion to use it to run the main pump does not seem very advisable.
Remember the 914 is an ELECTRICALLY DEPENDANT engine, and in case the
rectifier/regulator toasts, you'd be left with very few options. Unless
you design real electrical redundancy.
The architectures proposed by Bob Nuckolls are really worth examining.
Hope this helps,
Regards,
Gilles Thesee
Grenoble, France
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