shorted coil?

[Flux]

For the MOV to have any chance of protecting the rectifier it needs to be directly on the rectifier, otherwise any lightning induced voltages will not be clamped.

I doubt that you can cater for a loss of battery in real conditions, your 100v open circuit is very low and probably accounts for the poor power production you mentioned.  Typically I would expect a 48v machine to reach 100v oc at twice cut in speed ( say 14mph), at 28mph you would get near 200v, during a good storm with no load 300v plus is not unlikely.

A reasonable compromise may be to use a 200v MOV and use diodes rated at 1000v ( lower voltage ones are not a lot cheaper).

In the event of loss of load in a high wind you could loose the MOV but I think you would have more serious things to worry about.

If you keep things as they are with the badly matched stator you could run a 150v MOV and still not have it clip on load loss but your stator seems a better match for 24v from your description. Might be worth temporarily trying it into 24v to see how it performs.

Flux

[gww]

Flux
I built one of the turbines per hugh piggotts 2003 plans, which was ten coils, 21 awg 320 turns one in hand.  At 60 rpm it puts out 17-18 volts rectified but unloaded.  I have seen it while furling and hooked to the 48 volt battery in a massive wind putting out 1000 wattsfor maby 5 min per sears clamp meter checking the amps and x,ing the voltage.  The 100 volts was on a test stand that cleared the ground by about 6 inches.  While the other turbine was down it had one high amp at 16 amps per doc watson. 

The other turbine is the same but wound with 340 turns.  This was before I knew more was not better, blush.  It has two washers added for gap.

Hughs new recomindation for these turbines is 290 turns of 21awg or 2 in hand of 24awg.

I just add this incase something was missing.  I was hoping the non production of power was due to stalling, which is why I have some 12 awg wire between them and the battery and why I made the bigger blade.  If they are weak I don't know what I could have did wrong.  If they are weak am I correct in believing shorter blades and heavier wire would get the most out of them.   

I can't judge wind very well so it might be blowing harder then I think or wishfull thinking but it seems the turbine with the 320 turns is doing a bit better with the nine foot blades.

Don't get me wrong.  When I did the open voltage testing on the test stand the blades were moving and scary.  The 340 turn turbine only got to 80 volts.  Also you can tell they are moving when they finely start feeding the battery.  I do think they produced a bit better when the battery got higher but that may be my imagination.  I used standard boards for the blades and the 320 turn one had 5 and 1/2 inch cord and the 340 turn one had a cord of 7 and 1/2.  Hugh calls for 6 inch cord.  I always atributed the 100 volt compared to 80 volts to blade speed.

Please comment one more time even if it is the same result as above cause I know you know your stuff.
Thank you
gww

[Flux]

Sorry, I thought you meant that the most you had seen was 100v in a high wind up on the tower. 100v low down on a test stand would seem normal, in fact even cut in would seem very fast that low down.

From the new information I would tend to agree that you may be stalling so lets wait to see how the bigger blades work out, the higher voltage machines stall a lot easier as the line and rectifier losses are low in comparison with a 12v machine.

Estimating wind speed is far from easy, most people think it is windier than it really is, especially in summer when there is not much high wind to act as a reminder.

Flux

[gww]

Flux
Thank you very much for the responce.  I don't mind being wrong but always like to figure out what caused me to be wrong so I can adjust and maby fix or not make the same mistake again.  I THINK I am on the right track, If my welds hold and bolts don't come lose and all the other things I can screw up on don't happen.
Thanks
gww

PS  come november I won't have to guess on wind speed if we have a couple of days like we had last year.  The 8' blades survived that and I let them run to see if they would.  Interesting times ahead.

[gww]

Another qwestion.

I have a lattice tower that I will get up sooner or later.  I have 180 feet of it.  I will probly go 80/100 feet high. 

If I make new blades for the turbine that I have 340 turns on the coil, As hugh now recomends 290 turns 8 foot blade, Should I also make 9 foot blades or would 9.5 or 10 foot blades match the stator better?

Thank you
gww