On Wed, 29 Apr 2009 11:22:32 -0400, Wayne.B
wrote:

On Wed, 29 Apr 2009 08:39:55 -0500, Richard Casady
wrote:

On Wed, 6 Nov 2002 11:02:15 -0500 (EST), (Ron
Thornton) wrote:

Whenever I have shorted out an alternator, the diodes blow in about 2
nanoseconds. If the alternator output to the battery shorts, the source
for power becomes the battery. So it you are going to fuse it, fuse it
at the battery end cause the other end (diodes) opens up real quick.

A fuse can go anywhere in a wire, it makes no difference, the current
is the same everywhere along the length of it. And I will just bet the
diodes would protect any fuse by blowing faster.


Putting a fuse in the output of an alternator is not a good idea and
contrary to normal practice. If the fuse blows the alternator will
be running with no load which will increase the voltage level and
exceed the PIV rating of the diodes. The output of the alternator
should go directly to the engine starting battery. Any other
connection such as a house bank can be fused however.

If the alternator is producing electricity and you open the connection
to the load it probably will blow the diodes. In fact West Marine,
among others sells a diode to wire across the output terminal to
ground to dissipate the IV.

Cheers,

Bruce in Bangkok
(bruceinbangkokatgmaildotcom)