Bearing/axle load capacity for 17ft and 20ft turbines

[malvalio]

I am reviewing my plans for 17ft and 20ft turbine and upon checking the 17ft and 20ft deisgn on the otherpower website and book both appear to talk about a 6000lb axle for the 17ft, I have purchased a couple of 3000kg (6600lbs) units 6 stud M16 (5/8") on a 205mm pcd (8") and originally planned to use these for a 17ft unit, but it now looks overkill (well over engineered) the other power 20ft page talks about the 6000lb unit being approx twice the capacity of the 17ft design (and a much larger stud/pcd and shaft size) I have tried to find details of the bearings on line but so far have failed to determine the load capacity of the 2 units to allow me to find equilivants in the UK.

Anyone else have a few clues, I have found a 1500kg with the same stud/pcd as the 3000kg units I have so the flange is great but the shaft is approx 1/3rd smaller (2" approx and not 3" of the 3000kg unit and so think the 1500kg may be enough?

I am very happy to be safe and use the larger unit on the 17ft version but would like to understand the loads I can expect.

Denis

[fabricator]

I think your 6600lb units are perfect for a seventeen footer, definitely not too much overkill IMHO.

[taylorp035]

Maybe you build your own with some double or even quadruple roller thrust bearings from timken.

http://www.timken.com/en-us/Pages/Home.aspx

[dlenox]

Use the heaviest hub you can get, 6600# unit is good, for 17 or 20 ft turbine use the rear seal to keep water/dirt out.

If it is 6 stud so much better than 5 stud as this way each blade will have 2 studs back to the hub, 5 studs complicate how you lay things out (when using 3 blades).

It's the outside (smaller) bearing that seems to take the most abuse, the farther in 'toward' the bearings is best, as any overhang will exaggerate the problem.

Dan Lenox