Ralph Day
2nd April 2010, 17:24
Thanks to Mario my H80 is once again producing power.
Short story is: the unit started to make grinding noises and would freeze up/stop in the bitter cold. I'd been told bearings would last 5 years and this behavior began at 5 years and a couple of months. When the unit was brought down it would not turn at all. The yaw bearings were slow and grumbly (so following the wind was always behind).
Called Mario, who's done this before, and tore the unit apart in his shop. Pressed out the worn bearings, purchased new ones ($68, 3 on the rotor, 2 for the yaw) not bad. Another morning to press the new bearings onto the shafts and into the housings and ready to fly again...except...
There is a kit for the furling pivot...shaft, nuts, washers, bushings and pin. Total cost US $78, plus taxes, plus shipping, plus duty etc etc. I figured I could do without changing the pivot stuff, until I put the castings back together and saw how much play there was. The play was not from the worn bronze bushing but from the steel pin (threaded end) passing through the aluminum housing (top half of the turbine containing, well, everything!) The hole had become oval instead of circular, hence the play. What to do?
Local tractor service and parts place to the rescue, they sold a variety of bushings. I purchased one that was close in sizes, bored it out to fit the pin, then drilled out the old oval hole slightly larger to fit the bushing. In a perfect world this would have been machined or done on a drill press, but all the wiring was epoxied and tucked away in the nacelle so lazy Ralph didn't want to re-do a couple of hours of work. With the bushing piece cut to length, about 3/8 inch long, I gooped it up with anti seize and put it all back together.
TOday we (spouse/helper/bill payer) re-installed the turbine, blades, tail on the mast and sent it back in the air. As soon as the brake was off it started spinning in a really light wind...not since brand new has it performed so well in light wind. Once a high wind comes along I'll see how well it furls. Lately it had been sticking in the furled position (I tightened the pivot nut...like the manual says not to).
The grinding noises were not just disintegrating bearings...there was wear on the magnets on the rotor where they had been making contact with the stator (rotor on the outside, stator on the inside). Not much damage so some paint on the magnets and some varnish on the stator took care of that. You could even see a little wear on the aluminum housing where the edge of the rotor can had impinged on it. Worn bearings on precision equipment should not be left until near destruction...next time I'll know to replace them early!
All in all a fun week. Last activity on the microFIT front was sinking the racking anchors in the concrete pad last Saturday. 8 hours of diesel generator, compressor and hammer drill running, and epoxying the 3/4 threaded rod pieces in. And that's with 2 people working...glad I didn't tackle that alone.
Ralph
Short story is: the unit started to make grinding noises and would freeze up/stop in the bitter cold. I'd been told bearings would last 5 years and this behavior began at 5 years and a couple of months. When the unit was brought down it would not turn at all. The yaw bearings were slow and grumbly (so following the wind was always behind).
Called Mario, who's done this before, and tore the unit apart in his shop. Pressed out the worn bearings, purchased new ones ($68, 3 on the rotor, 2 for the yaw) not bad. Another morning to press the new bearings onto the shafts and into the housings and ready to fly again...except...
There is a kit for the furling pivot...shaft, nuts, washers, bushings and pin. Total cost US $78, plus taxes, plus shipping, plus duty etc etc. I figured I could do without changing the pivot stuff, until I put the castings back together and saw how much play there was. The play was not from the worn bronze bushing but from the steel pin (threaded end) passing through the aluminum housing (top half of the turbine containing, well, everything!) The hole had become oval instead of circular, hence the play. What to do?
Local tractor service and parts place to the rescue, they sold a variety of bushings. I purchased one that was close in sizes, bored it out to fit the pin, then drilled out the old oval hole slightly larger to fit the bushing. In a perfect world this would have been machined or done on a drill press, but all the wiring was epoxied and tucked away in the nacelle so lazy Ralph didn't want to re-do a couple of hours of work. With the bushing piece cut to length, about 3/8 inch long, I gooped it up with anti seize and put it all back together.
TOday we (spouse/helper/bill payer) re-installed the turbine, blades, tail on the mast and sent it back in the air. As soon as the brake was off it started spinning in a really light wind...not since brand new has it performed so well in light wind. Once a high wind comes along I'll see how well it furls. Lately it had been sticking in the furled position (I tightened the pivot nut...like the manual says not to).
The grinding noises were not just disintegrating bearings...there was wear on the magnets on the rotor where they had been making contact with the stator (rotor on the outside, stator on the inside). Not much damage so some paint on the magnets and some varnish on the stator took care of that. You could even see a little wear on the aluminum housing where the edge of the rotor can had impinged on it. Worn bearings on precision equipment should not be left until near destruction...next time I'll know to replace them early!
All in all a fun week. Last activity on the microFIT front was sinking the racking anchors in the concrete pad last Saturday. 8 hours of diesel generator, compressor and hammer drill running, and epoxying the 3/4 threaded rod pieces in. And that's with 2 people working...glad I didn't tackle that alone.
Ralph