Hi Folks,
I've been wanting to post an update on this turbine. It's finally up and running. For now it is mounted on just a guyed stub-pole tower section, about 25' up. It has been nice to be able to keep an eye/ear on it, and make a few adjustments without having it 100' off the ground. So far I'm only running it when I'm home to monitor things.
Briefly, here's the overview:
15' dual-axial, 16-pole
Mag rotors: 32 - 3x1.5x.75 N42 Ndfeb
Coils: 12 coils – 2-in hand, #14 AWG, 53 turns
Cut-in: ~92 rpm, 58 VDC
No slip-rings, SO “twist cord†with strain-relief
Here's what is a perhaps a bit different:
Coils are individually potted with T& G sides interlocking the 12 sectors. We used a ‘thermally conductive' epoxy encapsulant; coil cores are open for cooling.
During assembly the magnet rotors are gapped and mounted to the spindle, then the stator is positioned and centered. Conceivably the stator can be removed without jacking apart the rotors.
The stator bracket is stainless and is fastened to the spindle using a keyless bushing. It can be removed if needed.
The blade hub plate (1/2†A656) is also the upwind magnet rotor. There are stainless magnet rings that position and assist with holding the magnets in place.
The tail-boom is telescoping AL tubing, so the length can be adjusted (3 positions). The tail hinge has bronze graphite radially bearings and a recessed greasable, roller pin thrust bearing.
The yaw bearing is a graphite/alloy composite thrust washer. The radial fit between the yaw-head assy and the stub tower is greasable (I know, a bit of a contradiction in objectives).
The tail can be manually furled with a hand winch. 4 mm dyneema line (thank you Frans) runs thru a pivoting pulley head. The line is held in tension with a ‘sash weight' in the stub tower.
Rectifier:
There are two isolated, full-wave stud mount diode bridge rectifiers.
RPM gauge (Brian Smith's)
Controllers:
Midnite Classic 250 (2)
“Waste not†diversion to water pre-heat
Homemade ‘clipper' and high-limit voltage sensing relay
Still have to lots of tweaks to make - dialing in the curves, adjustments on the Aux settings, furling adjustments - but, so far looking good. And, still too soon to know which changes work and which we'll live to regret. For now this is where things. Many folks to thank here for helping me get this far.
prior post on potting coils & mag rotors:
http://www.fieldlines.com/index.php/topic,147846.0.html kindly, ~kitestrings