Hi
As stated in the original post, "The Kiss is a three phase permanent magnet alternator. The three phases are brought down the mast and there is a switch (to short the phases and stop the turbine) and a rectifier in a box inside the boat."
I was feeding the DC output from the rectifier into the LVM regulator. When I bypass the regulator by moving this connection direct to the batteries, the turbine works fine and charges as expected. I have considered the possibility of a blown diode causing there to be some AC on the outputs of the regulator, but I would expect to see some vibration in the turbine then. It is in fact running very smooth and quiet.
"It would seem that you would be able to reconnect the controller as a dump load only controller and wire the rectified output of the turbine directly to the batteries."
It is not possible to connect this particular regulator to the batteries only as a dump load. It is built to divert the power that comes in on the input terminals to the dump load when the measured voltage on the batteries reaches 13.9 to 14.2V and above. The regulator is built for and normally sold with the Aerogen 6 wind turbine and is designed for charging sources up to 40A, but I can not see any reason it would not work with any wind turbine or other charging source with a DC output. It is completely baked in epoxy with only a small hole for the potentionmeter that adjusts the cutin voltage, so no modifications would be possible. And it did seem to work just fine on the bench with a variable voltage DC power supply as the charging source. It was not designed to divert the power at the battery terminals to a dump load, only the energy that goes through it from the input terminals to the battery terminals.
It was not a case of the battery voltage being high enough for the dump load to cut in. The owner's father took the boat sailing for a week and never ever saw the turbine spin. Not when sailing, not when anchored over night with the engine stopped and consuming power for lights, the fridge etc. There are no solar panels. The only other charging source is the engine which is rarely used on a sailboat except for leaving and entering port and for charging the batteries when there are no other functioning charging sources.
The turbine wasn't spinning up and then stopping, it was not spinning at all, or only occasionally spinning very slowly in gusts. Way below cutin RPM. Maybe something like one complete revolution in a couple of seconds, and only in the strongest gusts. When turning it by hand, it felt stiff, like stirring molasses. This is the same way it behaves when the three phases are shorted by the stop switch. When I arrived on the boat yesterday, the house bank was at 12.1V at rest dropping to 11.9 when I turned on a 1.5V load (a lamp). In other words, the house bank was very nearly empty. We have had high winds for several days, so this again confirms that the turbine has in fact never charged when the regulator was in the circuit. The starter battery which was connected to the other output of the regulator was at 12.6V which is normal since this battery is only used for cranking the engine. The battery voltages were confirmed by the onboard Link 2000 battery monitor as well as my own multimeter.
When I bypassed the regulator, the turbine started charging and seems to be working normally. In fact, I'm quite impressed by the performance and how quiet it is. Looking out my hatch now at the boat which is moored 200 yards away from mine I can see the turbine spinning quite happily. I'll go over there later today and possibly tomorrow to check the battery voltage and shut the turbine down when the batteries are fully charged.
Owen