Mike,
I am bit confused by your comment regarding the slow blow fuse. I thought
Paul was asking about the main 30 amp alternator fuse, which is there to
protect the alternator wiring, not protect the system for over voltage,
Surely, even with the crowbar circuit, you still need a 30 amp fuse in the
main alternator feed line?
Brian Davies kit 454
----- Original Message -----
From: "M.J. Gregory" <m.j.gregory@talk21.com>
Subject: RE: Europa-List: Electrical questions
>
> Paul,
>
> Further to the previous answers, there are two principal reasons for
having
> a switch between the alternator output and the bus bar: first, to enable
the
> bus bar to be isolated from the alternator in the event of an electrical
> emergency (if smoke came out of the wires, switching off the battery
master
> would still leave the alternator feeding the bus as long as the engine was
> running); second, having followed the Rotax recommendation to feed one
> electrical pump for the 914 directly from the alternator, the bus
isolation
> switch avoids that pump running from the battery whenever the battery
master
> switch is on with the engine stopped (e.g. if you wish to set up way
points
> on your GPS before starting).
>
> The reason for having a slow-blow fuse is to avoid nuisance trips caused
by
> current surges. This requirement can be satisfied with a standard (as
> opposed to a "fast-acting") fuse. However, if you are planning to
> incorporate overvoltage protection you will need a circuit breaker and an
> alternator relay rather than a fuse to follow Bob Nuckolls' advice (see
the
> Air Electric Connection circuit Z 7 designed for permanent-magnet
> alternators such as on Rotax 912/914).
>
> Mike
> Europa Club Safety Officer
>
> -----Original Message-----
> From: owner-europa-list-server@matronics.com
> [mailto:owner-europa-list-server@matronics.com]On Behalf Of Paul
McAllister
> To: europa-list@matronics.com
> Subject: Europa-List: Electrical questions
>
> <paul.mcallister@qia.net>
>
> Hi all,
>
> I am at that interesting stage (not sanding & filling). I have a couple
of
> questions.
>
> 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 ?
>
> 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.
>
> 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.
>
> 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.
>
> I welcome any comments.
>
> Thanks, Paul
>
>
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