Yea, I know, another stator failure

[Seekscore]

I was thinking of the dump load and the batteries providing the loads. I may be wrong, but I think in my case this is incorrect. I am using the Xantrex C40 charge controller. It is set up to in the diversion load configuration. I know it does monitor battery voltage and when the voltage gets to around ~28.5v it diverts all input power from the batteries to the dump load. Once the battery voltage gets down below that set voltage it then diverts the power back into the battery. One or the other as I see it. If that is the case, wouldn't a too small diversion load cause the turbine to over speed in high winds because there is not enough of a load on the turbine?

A load controller just monitors the load on the battery and doesn't let it discharge completely.

Thoughts?

Mike

[Seekscore]

I double checked the angle of the tail pivot and I didn't get it exactly 45 degrees. It is 35 to 38 degrees. Not enough of an angle. Looks like that may be the cause of  the burn up by too much power. I'll post some pictures later. Pictures which don't exceed the size.

Mike

[DanB]

Hi Mike - you probably got my email.  But yes, what you describe there is a problem.  Using it as diversion, it should be between the batteries and the heater - definitely not between the wind turbine and the batteries.  Did you fry the controller?  I should expect you would if it's wired up that way, I don't know what sort of voltage they can tolerate.

[Ungrounded Lightning Rod]

I'd run diagonal straps from the stator end of each bolt to the near-hub end of the next, forming truss triangles.  End of the strap could double as a wide "washer".

I'd also double up the nuts and use the second one as a jam nut against the first one.  Then you're not depending on the crush strength of the stator to keep the nuts tight.  (Even if the stator crushed out and loosened up it would just rattle around on the threaded rods between the locked nuts.)

[ChrisOlson]

The 10' turbine, wound with AWG 14 wire for 24V is on precarious ground with sustained outputs of 700 Watts or more in my experience.

AWG 14 is good for 20 amps sustained in a coil and it'll usually handle 10% over that for quite awhile without a problem.  If the batteries are hammered so they take amps easy and you got a good wind - you're right - a single strand of AWG 14 is pretty light.

--

Chris

[DanB]

I maybe crazy but I've been doing it for years.  Really - if you work out the torque on  say... a 17' machine with 6 bolts around the stator things are much worse (there is a lot more torque on each bolt), and its still not a problem in my mind.  That said.. it never hurts (especially in wind power) to make things stronger.

[Ungrounded Lightning Rod]

AWG 14 is good for 20 amps sustained in a coil ...

Even if the coil is embedded in insulating plastic?

(I damn near started a fire the time I left most of an extension cord coiled up in a plastic salad storage container when I used it to power an appliance in a parked travel trailer.  The heat from many turns adds up quick, and if it can't get away because the air can't move past it...)

[Dave B]

Dan,

  Thank you for posting and explaining clearly to those building from your plans the limitations of the design and variables that can cause problems.

  As you clearly state, almost all issues and or problems you have seen have been caused by a change or multiple changes in the design.

  It is a very successful design as built. It is huge for people to understand that building one "similar to" "looks pretty much the same as" "this should work about the same as" and on and on can be in very short order a recipe for disaster. It is no longer the same machine.

  As far as the gyroscopic forces go (or call the poor furling performace wind seeking if you prefer) I have proven (to myself) that the relationship of offset side to blade rotation is very significant to the furling performance.

  I will again refference this video http://www.youtube.com/watch?v=IEwAry0GARw which explains perfectly the results I see. A CCW blade rotation and an offset to the left has the blades fighting into (or seeking) the wind instead of rolling away from it. Conversely (CW rotation and offset to the right) the same results will happen only in the other direction.

 Now change the relationship to CCW rotation and offset to the right or CW rotation and offset to the left and you have the blades wanting to roll away from the wind thus working with and not fighting against the furling.

  My observations with my machines and corrected 100% with changing to the "assisting" relationships indicated. My blades are different, my tail angle is different, my offset is different and on and on. There is no right or wrong but, if you are cursed with the wind seeking, non-furling burned up another stator over speed scenario .... you might want to take a look at the offset / rotation relationship. It may or may not help with your particular machine.

  Dave B.  

 

[ibeweagle]

sorry for your loss but been flying a 12 footer for 2 years now with 2 in hand #18 using hugh inspired turbine with improvements in cooling they say Ive got a #18 wire burnner well gess Im still here with no burn out and seen over 40 mph gusts email me if you like ibeweagle@hotmail.com