| For the last few weekends I've been working with the 3.2m axial mill, doing some yearly maintenance, and also installing some upgrades.
The maintenance stuff was all rather basic. I did some re-painting, gave the generator parts and the rotor new coats of paint. The paint on the magnet rotors was flaking(luckily no rot on the magnets yet), but on the blades it was just starting to get dull. Looks much more nice now, with brand new white coating =). The rotor also got balanced again, it turned out to be a few 8g FMJ's out of balance.
The need for upgrades was discovered last winter, when in a storm the furling proved to be non-working. (see link: http://www.fieldlines.com/story/2008/11/11/151034/60 )
To help avoid this happening again, I've welded together a new frame, with more offset. Now the offset is 180mm, 50mm more compared to the old one which had 130mm. It'll be interesting to see how this configuration performs when a good storm hits.
Also, with the new frame I dithed the car spindle as yaw-bearing setting, it was just trouble. The easy yawing made it hunt a lot more in qusty wind, making the life harder for the turbine, and also cutting output. Now the "bearing" is just a pipe over pipe arrangement. The tail stop is now welded at about 10 degrees off center, to compensate the turbine running slightly off wind at normal operating speeds.
It'll be interesting to see, how this new setup works when a good storm hits. So far, it has only seen medium winds, and it now seems to start furling at about 20A (12V system). I might try bit heavier tail later, to increase the output a bit.. Though even with the current settings my 200Ah battery bank will propably be in a dumping mode when winds that high hit the turbine. A bit more than 20A when the picture was shot:
The tower got a new coating of tar, and of course I had to install a new tower stub, to fit the new kind of yaw bearing. The tractor PTO generator comes in really handy in a remote welding job like this =)
When it came to the time to put the generator back together, I noticed it was very hard to set the air gap. As it turns out, the stator has warped a little. I don't know if it's just the nature of the polyester resin, or if running with the 100A+ output in the last winters' storm was the cause for this.. anyways, if it gets warped any more, it will have a date with the dumpster, and I will have to dig out the stator mould again.
Notice the grease nipple in the middle of the bolt pattern.. I removed the front seal from the spindle bearing, and installed a grease nipple(with extension pipe) to the dust cap.. Now i can pump new grease on to the bearing without taking it all apart (useful, if for some reason there is no problems discovered in the maintenance.)
So this is how the turbine looks now. The added guy wires (2nd set to the middle) together with the rebalanced rotor even got rid of the oscillating tower at low power levels. All good for the storms to arrive =)
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