In article ,
Wayne.B wrote:

Doug, can you cite some references on that? I've never heard of
anyone recommending 100+ amps without dual belts. I used to run a 120
amp Balmar on one of my old sailboats with a single belt. Frankly it
left a lot to be desired even at 50 to 60 amps - lots of squealing and
chewed up belts. It would never get even remotely close to 100 amps,
even for short periods. The belt slip was just too much for it.

Ok here we go with the Math...... 120 amps @ 13.6Vdc = 1632 Watts
figure that you alternator is say, oh 75% efficent that equals
2175 watts of input energy, which equals 2.916 Horespower.
Now 3 HP thru one belt? Well, it can be done with a C size belt, but
most engineering folks like to spec max 1.5 HP per belt.

So two belts would be prefferable for 3 HP worth of work.

The above assumes Vbelts, and not gear-belts which can easily
handle up to 6 HP with no problems.


There are belts and there are Belts, so lets get the definitions
set down first......


Bruce in alaska who is running a 6 HP air compressor on a 2.5
inch gearbelt off my 4-108 Perkins 10Kw genset
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add a 2 before @