Status as of 6 Nov 2002: The wind system is up, running and charging, but not generating as much power as before. We are investigating.

The University of Colorado Mountain Research Station Tundra Lab, located at the "Saddle" on Niwot Ridge is the perfect testing grounds to examine extreme weather conditions for the wind power unit. This 11,600 FT. station experiences a January mean temperature of -13.2 degrees Celsius as well as constant winter winds and gusts up to and above 100 mph, which should be an excellent test of exactly how "Maintenance Free" this unit really is.

On October 4, 16 days into the testing, the wind system tower was observed via web cam to be tilted severely. An emergency repair trip was scheduled for the morning of October 5. We had speculated that one of the stakes for the supporting cables had failed. Upon arrival, we found that this was not the case, rather, the base coupler had shifted to the end of the base. The entire structure was shaking violently, as winds were a constant 40-60 MPH. Upon stopping the generator from spinning, we found one of the blades had broken off. The question at hand was: Did the blades break off as a result of the tower shifting or did the tower shift as a result of the blade breaking off?

After analyzing the data (see below), it appears that at 23:00 on October 3, there was an immediate dropoff in current generated by the generator with no other gradual or immediate changes. This event coincides with a 65 MPH gust measured at the MRS Lab, which is located approximately 1000 yards North West, and does not exerience as powerful of winds as the wind site does. Is is speculated from this data that a large gust caused a blade to fail, which in turn put the system out of balance and caused the base to shift.

As a result of the maintenance trip, the following issues will be addressed:

• Rigging: on the last visit, rigging for all four stakes and the tower base was enhanced. Future guidelines should include that system is over rigged to at least double the considered minimum.

• Blades: UNAVCO will contact Southwest Wind Power to discuss issues concerning blade falure in extreme weather.

• Enclosure: in addition to turbine issues, the enclosure was also found to be heavily drifted with snow. Enhancements to the weather proofing of the enclosure will be addressed.

• Divert & Dummy Loads: after just two weeks, the hand made loads were in tact, but weren’t in the best shape. Will discuss possible replacements.

On 14 October we returned to the site with a new set of blades and sealed load box. The system was put back up with all the additional rigging from the last trip and the guy wires were pulled extremely tight. As an added bonus, the shape of the ground allowed us to erect the tower with static tension INTO the wind. The result was an extremely tight tower that can not wiggle or vibrate nearly as much as the initial setup. The new load box is a sealed cast steel box with two ceramic power resistors that are mounted onto hollow aluminum tubes that protrude 5" out each end of the box, allowing heat to easily dissipate, but keep moisture out. In addition, we used thicker weatherstripping on the equipment box and used a cam strap to tighten it shut.

The result was an extremely solid system that is VERY quiet. The initial setup could be heard in strong winds from about 3 miles away. We could not hear this system more than 50 ft. away. Vibrations in the tower and wires are minimal and the blades/unit appear to track very straight. See the pictures below.

Data update - 21 October 2002: The first several days of data are shown below and the results don’t look good. Power levels from the generator are extremely low, especially when compared to the first three weeks (above:  Wind System Data - Tundra Lab - Sept 18-Oct 7). Investigation is underway, however, it appears that the system is still functional, even under the lower power.