My Windspot 3.5 Fail and repair

[Peter Klaassen]

I am posting this for the benefit of those who have a similar turbine - things I wish I had known ahead of time and what warning signs I missed which cost me some headaches and expenses. This turbine seems pretty good, but the Do It Yourselfer needs to be better educated than I was. I am 2900 km away from the supplier of this turbine and even further from the manufacturer in Spain.

So- to look at the failure of the hub and blade holder

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The first two photos show how the key and keyway of the generator shaft have worn. This was due to a slackening of the one bolt which holds the mounting plate of the blade hub onto the shaft of the generator. I am guessing that this bolt had started to loosen when I first put the turbine in the air. I did not have a good electrical connection at the slip rings and the turbine made a loud moaning noise when producing 2kW or more. Arcing at the one bad slip ring caused only 2 of the 3 phases to make power and the uneven load caused vibrations in the generator and mast. In hindsight I should have taken it down to see what was going on. The other issue may also have been caused by these vibrations and that was pitting in the blade holder bearings and slop at the blade holder shaft. In the 3rd and 4th pictures you see an original blade holder and the one made here in Wellington. Grease running down the shaft is a warning to stop and fix the bearings. The renewed blade holder is slightly heavier in weight with a clamped on flyweight instead of a casting. The failure of the blade holder happened during a winter storm last year. The power monitor showed about 5000 W coming from the turbine. This year we have had a gale blow through with similar winds of 40 knots and the turbine topped out at 4000 W. The blade feathering seems to be working now.

[Peter Klaassen]

In these photos I have been more careful about proper position of the brushes on the rings and I have sanded down the brushes to match the rings.
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The turbine is almost silent now even when making full power. I have trouble hearing it against the background sounds of the wind blowing. The sounds that I can hear seem to be produced when the power is being sent to the dumpload. There is an electrical whine coming from the turbine as it slows down under the braking force of the dumpload.

[Peter Klaassen]

Today the Windspot came down for inspection and repair. It has been up since October and has been doing well. As it was on dump load in the past few days it was making a clunk. I have found that one blade is loose in the bearings. In the pictures the loose one has the grease leaking from the seal. The last repair was for failed bearings and a broken blade holder. It will be possible to look at the bearings again to see if they require replacement again.

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[Peter Klaassen]

These are two of the three Windspot blades. They are showing pits and cracks in the leading edge so I have gouged them out and applied epoxy putty. I will sand and paint the blades with two part polyurethane paint and put protective tape on the leading edge. 1345

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[Ralph Day]

It looks like gel-coat is failing Peter. Can you keyhole the repair a bit? LIke a dentist would undercut the tooth enamel to install a filling?

Good Luck.

Ralph

[Peter Klaassen]

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This is the casting which links all the blade feathering together. It has small cracks in the one lobe so I will have to wait for parts for repair. I have seen some where a second layer of reinforcement was used to fix this problem. Have to see about an improvement before putting it all back together.