Mayf;
Unless the latest alternator designs have changed an alternator output
current is self- limiting to a degree; the magnetic path in the alternator
saturates at high current and its output current won't go any higher. This
saturation current is not well controlled, however, and I wouldn't depend on
that alone.
Instead of one 100A fuse or circuit breaker I'd recommend placing a number
of smaller breakers in series with all of your major electrical components.
Size the breakers to allow the normal load current. If you have a load of 5A
in a circuit branch, put in a 10A circuit breaker; this will avoid "nuisance
tripping" while still protecting against catastrophic short circuits. The
main purpose of a circuit breaker is to keep the wire from burning up due to
high current.
Now and then you can find small aircraft circuit breakers on eBay. They are
good and allow you to pull out their button to turn off the circuit if you
wish.
Regards, Neil Tucson, AZ
-----Original Message-----
From: land-speed-bounces+neil=dbelltech.com@autox.team.net
[mailto:land-speed-bounces+neil=dbelltech.com@autox.team.net] On Behalf Of
drmayf
Sent: Friday, October 26, 2007 2:03 PM
To: LSR
Subject: [Land-speed] Electrical Question (Sunbeam wiring)
Do alternators generally have fuseable links on the wire that goes to
the battery? If so, is it sized according to the alternator output? Ie
woul a 100 amp alternator use a link that is 100 amps? What about a
circuit breaker? Now at the back of the Sunbeam where all the hot wires
come together, I would like to add circuit breaker protection. Again,
how do I size it? Do I add up all the loads as if the alternator is not
running and size it that way? When the motor is running and the alt is
on then it takes away some of the need for the battery to send amps up
the wire. So It seems like the worst case would be when the motor is not
running but all the electical stuff is. Make sense? Oh, this does not
include the starter circuit..
Thanks for you help..
mayf
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