My ever increasing pile of dead mill bits

[shawn]

I now have a dead stattor to add to the pile of scrap :'(
the last picture is the wires going to the stop switch

[niall]

hi Shawn....

pity about the stator... ....was the mill dumping into a load when it overheated or did it break free from a "stopped" state ?

its good it didnt get into a complete runaway ...

[Wolvenar]

Wow that magic smoke might have been neat to see getting released..

[ksouers]

Sorry about the mill, Shawn.

Is this the one you just put up a couple months ago?



Kevin

[niall]

it is interesting ....

Jlt made a comment about a possible phase failure on fl...
it does "look"  like one phase is cold

thanks for putting this up Shawn ...maybe the alt looked for the point of highest ( then  lowest ?) resistance , and worked on that ....

if one phase dropped out, that might make the stator appear much smaller to that 4 m prop  ? 

stuff that goes wrong sometimes is the really interesting bit ....

140k winds ....

[Wolvenar]

Do you have any monitoring systems on your setup that could tell what it was pushing at its breaking point?
What kinda of wind was it facing?

This may be an example of why Chris Olson does not like this design.?.?.??

[frackers]

Ouch

Looks like one of the slip rings gave up and you only had one phase on the shorting switch. Looks like only one coil really burnt - I would have expected all 3 in one phase to look similarly crisped.

Do you want a hand with the rewind? I don't think I've got a work area any warmer than you have though!

Let me know if you need anything.

[shawn]

Hi guys one phase out was my first thought when I looked but looking closer showed at least one coil burnt on each phase so they all got hot.
I do have loging but with it shut down the power was going into the burnt wire instead of my bank then when that was toast I hand wound some bare wire around the output ac side to try and stop the beast none of it was fun those blades screamed and it took plenty of stupidity just to go anywere near it 
I have seen spikes of 140 amps easy with this mill so I would guess short spikes of 180? amps but they were just to close together and she cooked .

[shawn]

I had the afternoon off so I dragged the old coilwinder out and put in 3 inhand of 1.6 same amount of tuns this completly fulls my stattor (and some) with copper the old stattor only had 2 inhand of the same wire
As im rebuilding this im thinking of how  im going to make it live the next big wind it gets one idear is to make it furl even earler another thought was to put a lock in the full furl position like the old water pumpers ? 
Also i thought i might try another coil shape not sure which is best i will find out soon enough.

[jlt]

     I really like your bicycle coil winder . and by all means get the most wire you can in there.even if you half to make the centers smaller.

     I am going to add a small 10" actuator to pull the tail around on my next mill.Two means of shutting the mill down.If one should fail I always will have a backup.

     I like more forward offset in my machines. It helps keep them furled in high winds.

     Here is a picture of my 12ft stator. really had to cram the the coils to get them in.
I only have to short one phase to stop it.

[frackers]

I had the afternoon off so I dragged the old coilwinder out and put in 3 inhand of 1.6 same amount of tuns this completly fulls my stattor (and some) with copper the old stattor only had 2 inhand of the same wire
As im rebuilding this im thinking of how  im going to make it live the next big wind it gets one idear is to make it furl even earler another thought was to put a lock in the full furl position like the old water pumpers ? 
Also i thought i might try another coil shape not sure which is best i will find out soon enough.

I think I'd be tempted to start the rebuild with a set of 3m blades and only move up to the 4m blades once the rest of the system bugs have been ironed out.

I think the yaw bearing slipring/brushes may have to go though - the new coils will have the potential to push well over 100 amps and I don't think even the really good construction of the  sliprings you have will handle it.

I recall that you increased the forward offset quite a lot so thats probably OK - perhaps a different blade profile that stalls harder in high winds will help with the spring-time nor-westers.

I've got a new version of the software for the controller ready - nothing critical but it does tidy up a couple of things in the logging and introduces the idea of the self discharge of the battery bank by about 5% per week. Hopefully it will track the bank charge a bit better then.