Please remember that fuses and circuit breakers are there to protect the
wiring in the event of a current overload. A crowbar circuit, where
fitted, is there to protect the equipment from excessive voltage (as a
backstop to the voltage regulator), and would not protect the wiring from
excessive current caused by equipment failure or a short-circuit.
The 30 amp slow-blow fuse, as Andy Draper said, is recommended by Rotax.
This is matched to the permanent magnet alternator of the 912 series, which
has a drooping characteristic i.e. the voltage drops as more current is
drawn from it (see Rotax installation manual). If you fit a different
engine and alternator, then you should follow the recommendations of that
engine manufacturer. A higher rating than 30 amps may be appropriate if
the alternator has a higher output capability and you wish to make use of
it. In this case, you may also need to uprate the fuse/circuit breaker in
the battery supply line because, if the alternator failed when all your
equipment was switched on, the battery would supply the full load current
before you had a chance to switch anything off. You may need to uprate the
cable sizes: these must be capable of carrying the full rated load of the
fuses/breakers without overheating, and should also be large enough to avoid
excessive voltage drop at maximum load.
Fly safely
Mike Gregory
Europa Club Safety Officer
-----Original Message-----
From: forum-owner@europaclub.org.uk
Subject: Re: Slow Blow Fuse
Hi! Ian.
You are most probably correct but if you have the "Crowbar " protection who
needs the blessed slow blow fuse which you won't be able to have a try at
"reset" anyway.?
regards
Bob Harrison. G-PTAG
-----Original Message-----
From: forum-owner@europaclub.org.uk
Subject: Re: Slow Blow Fuse
Bob
May I suggest you have another think about your comments re starting. The
30amp slow blow fuse should be in the supply from the regulator not be in
the starter circuit.
Ian Rickard #505 G-IANI
e-mail ian.iicons@ntlworld.com
-----Original Message-----
From: forum-owner@europaclub.org.uk
Subject: Re: Slow Blow Fuse
Hi! Dave.
Why don't you forget the slow blow fuse and fit a "crow bar protection
Mod."? then just have the
solenoid isolater . I also was sick of blowing fuses due to start up loads,
so eliminated the slow blow fuse, although with the gear box reduction on
the Rotax you'll not be pulling the load required to start the direct drive
Jabiru 3300 six pot.
Regards
Bob Harrison G-PTAG
-----Original Message-----
From: forum-owner@europaclub.org.uk
Subject: Slow Blow Fuse
Hi,
One of the components that is driving me crazy is the "30 amp slow blow
fuse"
called out in the Europa electrical system! I can't seem to find the darn
thing! I have an 8 am fuse, but can't find higher.
What are people using for that and any ideas where I could get one or more?
Thanks,
Dave Anderson
A227
mini U2
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