Hugh: I would say that you should have
both that and a furling tail.
The tail does a different job by protecting against high winds.
But you also need to protect against over voltage/overspeed -
with all sorts of dangers.
---
I think that some kind of protection method
for high winds is at least needed.
Erkki Nousianen's machine in my pictures (below)
had originally a wind rotor with two blades
and a pitch control mechanism.
We made some time ago a new rotor with two blades
without the pitch control mechanism. The induction
generator didn't work and the rotor was broken
during a storm. Now he has made this new rotor
with eight blades (of quite similar design
as our design of two blades). His idea is that
this rotor will rarely overspeed.
The idea is that
the wind rotor with so many blades
would not vary its speed much
and moreover it
(because of the shape of the blades)
will become after some speed quite ineffective.
We will see, what will happen.
(More about the machine in my diary.)
The other machine in my pictures,
Kauko Kirmanen's machine,
has got only relays to switch
the load on and off.
The generator is an induction generator
with capacitors and with a gearbox
as with Erkki Nousianen's machine.
That machine has been quite successful
in that respect that it seems
to withstand high winds quite well
without almost any overspeed protection.
Probably because of the inefficient
and very robust blades.
I've been thinking about a system,
where the three phase induction
generator would be so big that
it could overpower the wind rotor
in most cases.
It seems to be that an induction generator
is quite happy with unbalanced loads
for the different phases.
At certain speeds first one phase load
would be switched on,
then next with a bigger load,
and finally the last with
an even bigger load.
There would be also a furling tail
to take care of even higher wind speeds.
Maybe also switching system for different
size capacitor banks would be needed.
What do you think?
Is it possible/practical to make?
- Hannu
