"Wayne.B" wrote:

Our *big* alternator is now a 320 amp Leece-Neville fire truck unit
driven by three belts. It has over 500 hours so far with no belt
changes or signs of premature wear. Even with the current limiting
resistor, the alternator causes the DD 6-71 diesel to audibly grunt
for a split second when I switch in the house bank.
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There was a time in my life when I was a Leece-Neville design
engineer.

Back in those days the large alternators (200+ Amp) designed for the
bus fleets had the AC terminals brought out to the case.

Common practice was to grab a couple of AC terminals and install a
single phase, half wave bridge across the AC which was then
connected to a DC relay with the contacts of this relay wired into the
field circuit.

SFWIW, field current was limited to 5 amps back then.

When the engine was starting, the field relay was open which basically
eliminated any alternator belt loading on the engine.

There is enough residual magnetism in the rotor & stator that when the
engine has started and up to speed, sufficient voltage is generated
to excite the relay and start charging the system.
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"Flying Pig" wrote:


But we DO have belt dust, a bit. Never had a squealer, though; our
alternator's only 70A and as far as I can tell, it's never
challenged the belt, particularly.
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You have a problem. Sooner or later it is going to bite you.

The better but not necessarily the easiest solution is to move to a
dual
belt system.

Since the alternator is not your primary recharging device, you might
consider increasing the alternator sheave diameter and staying with
one belt.

You WILL reduce the output, but by how much can only be determined
from an output curve.

Lew