I have two alternators on my main engine
, besides the standard Yanmar
12v one, which charges only the engine
start batt, I have a Leece Neville heavy duty school
, 110 amps x 24v.
I have gotten great service
out of that alternator
, but I did finally burn it up last summer, requiring an inexpensive rebuild
. I believe it burned up due to abuse, that is, due to my own stupidity in forgetting that I had left some large AC loads on it while using the windlass
and 10hp bow thruster at the same time, at idle speed. Yes, I know it was stupid. At the time this happened the alternator was already 12 years old and I have no idea how many megawatt/hours it had produced over the years without complaining.
Nevertheless, I would like to be a bit more careful with it this time. I have installed a temperature sensor (Maretron under-bolt ring sensor connected into the N2K network) on the negative post.
The alternator produces 80 amps or more than 2kW of power already at 1500 RPM
and produces full power of 110 amps or nearly 3kW of power before 2000 RPM
. When the batteries are down, they provoke the alternator to producing full power.
I had always monitored the temperature of the alternator by using an infrared thermometer on the case. How surprising to see that the core
temperature of the alternator, as shown by the temperature of the negative pole, is much higher. When the alt is producing full output, this can go to 110 degrees C or more, although the case never exceeds 60C. The belts will reach 70 - 80 C. Do these seem like reasonable temperatures, or should I be worried about a core
temperature of 110C?
I have an Adverc regulator
which turns the alternator to full power for a while, then cranks it back to let alt and batts rest, then repeat. I don't know whether this is good or not. For some reason, my batts got boiled almost dry last summer after a long motoring passage
(and I replaced them all, $$$).
Maybe after the batts are fully charged, this is not the best regulation regime?
Maybe I need to regulate the alternator to derate it a bit, and go to a real float voltage after the batts are full?
Anyone able to add to my knowledge, or give any helpful tips?