We just installed a new
motor on our
Lofrans Tigres
windlass. Previous to the old
motor failing, the
installation had run since 2014.
When running the
windlass, it was pretty wimpy, but popped the 150 Amp circuit breaker after about 1 minute light
work
We reset, same again
We reset, and then discovered that the gearshift had become stiff then jammed
Investigation showed that the part of the fwd/reverse Morse cable between the
engine and a point a foot aft of the
engine where the cable touched the aluminium
hull had melted the inner plastic sheath, jamming the cable. The outer sheath was badly distorted, and the cable was hot. There had clearly been arcing between the Morse cable and the
hull, presumably because the outer plastic sheath had chaffed through.
Our first thought is that there was a leak from the 12 volt positive cable driving the windlass which drove the hull positive when the windlass ran, and the
current found it's way to the engine block via the Morse cable.
After disconnecting the windlass, we find that all three terminals show essentially zero resistance to the body of the windlass. Of course the resistance of the windings is so low that if, say the negative terminal, is connected to the windlass body, the two positive terminals will show connected too.
Our ohmeter has a minimum reading of 0.1 ohms, so will see a very low resistance as a short.
My first diagnosis is that there is a leak inside the motor allowing some
current to flow to the body of the windlass, and the thence back to the
battery via our damaged Morse cable. Normally, the motor and the control cable are isolated from the hull
Anyone else have a better diagnosis?
This did not happen with the motor that ran the windlass since 2014.
Solutions?
Being a metal
boat, it is impractical to electrically isolate the windlass, because even if we fit appropriate plastic bushes on the bolts, the
anchor chain will still connect the windlass body to the hull.
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