On re-commissioning Enfys last season we discovered that the engine's alternator was not charging. A quick check of engine wiring loom and controls revealed that the alternator was receiving its excitation voltage but the output was dead.
|N-D Alternator - Loose wire protruding from rear cover is a direct connection to one phase |
of the AC windings and provides a pulse-train for the tachometer
I removed the alternator and took it home. Usefully (not) the engine mariniser had sprayed paint all over the data plate making it illegible so it took a bit of detective work to find out that the alternator is a 'Nippon-Denso' with an output of 40A. It was the internal voltage regulator that had failed - there was no visible damage or corrosion - it just decided to stop working after the winter lay-up. I must say how poorly and cheaply-made this machine is; not really suitable for the marine environment, in my opinion. Pricing up a replacement showed that it was not cheap to buy though... despite being the same as used on plant-based Kubota engines.
|The regulator is the module on the left with a heatsink on its back.|
After a couple of attempts a correct replacement regulator was sourced from an auto-electrical parts supplier and the machine was re-assembled and tested on the bench by spinning it with my electric drill. Whilst in the vice I blew copious amounts of black dust, from the 'V' belt, out of the machine's internals.
|Connected up for test. My 'test' battery is a little tired.|