This is the Generator I rebuilt from a fan motor a few
years ago but never got around to putting up that many of you have seen on my
website.
Yesterday set record high temps yesterday on the Colorado plains and set off
some nice thermally induced winds. While the TV station said it hit 94 deg F in
Denver, my thermometer in the shade read 102. This gave us about 3 hours to
watch it spin and do preliminary tests before taking it down for alteration,
adjustment and getting out of the heat.
Above you
see the genny up on a 30' Rohn 25G tower overlooking a nice green scene. It will
be brown soon enough as summer's heat bakes everying to a crisp.
Here it
is on the ground before raising. I don't like how the blades are attached, too
bulky. I'll be changing that. The tail is a side furling arrangement with a 4
foot spar. The tail is at a right angle to the bearing shaft, which gives it a
droopy appearance. This too will be changed to look a bit more
conventional.
The furling
tail turns out to be the limiting factor on today's testing. While the rotor
self starts in a roughly 10 - 14mph breeze and gets up to 15 volts very quickly.
In wind gusts up to 30 mph or so the furling turns the rotor out of the wind
soon after reaching 32 volts (open). When furled, the voltage drops slightly and hangs
near 30 volts. I prefer to see 40 volts before leveling off. According to my
previous testing, 30 volts is generated at roughly 420 rpm and 40 volts at 540
rpm. Only when the furling stuck momentarily in a very strong gust did I see 40
volts. I believe the sticking was caused by flexing of the mast which pinched
the too long rotating insert. Shortening the mast and insert should eliminate
this sticking .
My camera
seems to have a pretty fast shutter. It was hard to find a picture where the
rotor appeared to be spinning. But spin is did for several hours.
I
hooked up a small 12 volt load during this time to test current output. This was
a 12 volt air compressor that draws about 6 amps. It was pointless to hook it to
my fully charged 24 volt battery bank. In a 10 mph wind (apparent to the blades
at least, causing ~240rpm and 20 - 25 volts open circuit) the load drew just
over 6 amps at 15 volts or roughly 100 watts without slowing the rotor
appreciably. I expect a dead battery or other stronger load would have had a
noticeable effect and shown more amps, but that's all I had at the
moment.
So down the tower came in the heat of the day so I can work on hub
attachments, furling and other details these few hours revealed. I'll write my
findings and conclusions after doing more tests with alterations made.
