If you make a furling scheme that works it will protect your stator in all winds. When it furls beyond a certain point the power will fall unless you go to great trouble to stop it doing this. At times it can be annoying to find that it is producing much less power in a gale than at the furling point, but at least it is safe.
If you need to devise something to force it further into furling then this is an admission that the thing isn't furling.
Proper furling will protect the machine in any wind. There are times on turbulent sites when things may be better off shut down in big storms but while you keep a tail the whole thing is going to wag about violently anyway.
If you can rely on a brake switch to hold it in all winds then you have the option of running it safely within the stator rating or stopping it. Having it stopped may reduce gyroscopic forces if it is yawing violently and this can be a better option on bad sites.
On a good clean site the thing will sit there furling quite happily and producing less than 50% of the maximum power at furling, if you need the power it might as well keep running.
Running things stalled has its attractions in that it keeps speed and noise down. it is probably safe to do it as long as the thing can't pull through stall at a wind speed where the furling can't hold the unstalled current to a safe value.
If you add enough series resistance for the thing not to run stalled you are more likely to get a furling system that actually works and once it does furl it will never pull through it. The end result is that you get way more power in all but the lightest winds, the main heating is in the resistor not the stator and you will be forced to make the thing furl rather than put up with the noise in high winds.
My advice is to well over build the alternator with plenty of magnet and copper so that it performs abysmally with no series resistance and then add resistance until it works at about peak power in your normal winds up to perhaps 25 mph, then furl it.
You then have 3 options. Let it run safely at maximum power with furling. Let it tick over producing some power at low speed with the resistor removed or brake it to standstill.
If it is designed this way with lots of magnet and copper it will always hold on the brake and most likely it will always hold in stall but in very high winds I would let it furl or stop it until you have proved beyond all doubt that it will not get away in stall mode.
I really think we are chasing a non existent problem but I came at wind power earlier with alternators that absolutely couldn't hold a mill in stall mode, it was just not cost effective to even try. It's something that has come about with neo magnets and iron less alternators and in many ways it is a virtue that they possess but don't kid yourself about furling most of these things don't. It may assist stall regulation but it is mainly stall regulation that most are seeing.
I have never been able to use such heavy tails and i am now convinced that at least for the way these machines are running the offset needs to be more than 1/2" per foot.
If you add series resistance and get it clear of stall and reduce tail weight you may still find that offset enough. In view of the tail weight issue if you must continue using massive sheets of plywood then I think the 20 deg hinge angle needs reducing.
Flux
