Re: 24v alternator pulley

James Alton


High output alternators and their pulleys can run pretty hot even when properly set up which seems to be a big factor in the dust problem and the early failure. With twin belts it is of course critical that the two belts be a perfectly matched set so that they share the load equally so try to buy belts from the same batch and don’t mix if at all possible. I had a customer with a twin belt setup with a 200 amp large case alternator that was going through belts in a relatively short period and what a mess the engine room was. I switched him to the Gates Fleetrunner belts used for long haul truckers and the belt dressing was greatly reduced and the failures pretty much stopped. Marine Pro liked the belts enough to begin putting them on customers engines too when possible. Might be worth giving them a try though unfortunately I have sometimes had problems finding the exact size that I needed.

Best of luck,

SV Sueno, Maramu #220
Now high and dry in Preveza

On Oct 25, 2019, at 4:27 AM, ngtnewington Newington via Groups.Io <ngtnewington@...> wrote:

I am still not completely happy with the 24v 175A alternator installation on Amelia.
There is belt dust that is annoying, and they do not last very long.

I have checked the alignment and it is pretty good.

The alternator is nearly new.

I have a smart regulator that ramps up the load gradually.

The two idler pulley are not perfect. So I will have them machined down say 0.5mm and new bearings and check they are true. Maybe this is the problem?

The faces of the grooved pulleys are smooth.

So far the best belt in terms of longevity is the Mitsubishi Set Free SPB 1320LW.

Belt tension; I do not have a gauge and do it by feel. Perhaps it is time to buy the tension gauge?

What I am beginning to think is that I should change from twin v pulleys to a Serpentine grooved pulley with a single wide belt. I
could use the existing idlers and the tensioner. Change the PTO pulley and the alternator pulley.

Has anyone done this?

Or does anyone have any thoughts.

S/Y Amelia anchored in the south of Peloponnisos
AML 54-019

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