I like his problem-solving attitude.
That looks good Christof. Did you get the same data than Rod? He recently did a peak at 1000W, 140 RpM, 70N.m
Do you have a brushless FOC control ESC?Iā I gave rod a little help on that some months ago. We use Vesc board that are really fine!
Unfortunately Christof is not part of the forum yet. You can ask him on twitter or youtube or drag him here.
IāLL mail him to invite him
All,
Thanks for the invite and the positive feedback! Planned on joining for a while - but when I am in ābuild modeā itās hard to get me out of the workshop
@Kitewinder: Yes I am using a VESC 4.12 (not the fancy V6 that Rod is using ;). I am controlling it with an Arduino and a PID library (adding this to the system was the main part of this weekends test) The controller works great thanks to Keith!
I am far away from Rodās kW. Here is why: I have a 190Kv BLDC generator that is not spinning fast enough with the 1:2.5 belt drive I had at hand. Somewhere between China and Spain is a box with a 45Kv motor and a new belt drive. With that I hope to get to the 350W that the rotor is designed to get @120RPM in 10m/s wind. More than happy to reach out to you once I have put it together to get some help!
The other important upgrade were the new connectors. I can now build longer Helices way more efficiently than before. The printer is glowing - making the 200 I need:
to build a 100ft version right after the holidays.
On a side note: I have never been gone Just moving from the US to Spain with a family of 5 is not an easy project either. On the positive side now I have plenty of wind and space and do not have to worry about homeland security asking why I am flying strange objects close to Logan Airport
Enjoy!
/cb
Welcome!
Is that a Zortrax printer?
Thatās a Raise3d N1 Dual - āhalf price off because end of productionā - printer. Upgraded to a Bondtech extruder because the out of the box one suā¦ed.
/cb
What for the PID? The Vesc has an FOC control mode for
Position control
Speed control
Current Control
Regenerative braking
I would guess that is enough to do anything needed. On kiwee we use FOC control with position control to reel in and regenerative braking for the power curves.
The rig looks really nice. Thanks for sharing
But wait, there is more!
Couldnāt wait for the rest of Team Tueddelpower to be able to come to Spain from Germany (fā¦g Covid) and took the all new base station out for a flight yesterday.
Good news: The system made the 100W I was hoping for and the new base could handle a lot more.
Bad news: We used a chinese controller with build in āemergency breakā instead of the VESC. The break kicked in and overloaded the helix. Hope Keithās has his new software release with torque limit ready soon
Anyways:
I will upload some more detailed footage and documentation over the next days.
Enjoy!
/cb
Wow
The uniformity and initial torsional rigidity of that shaft under tension is amazing.
The best bit is we also got to see a fail at the end. Thanks @someAWE_cb /cb
What I like about the fixed angle video is how easy it is to pinpoint the geometry of the working system.
We can see wiggle and wobble in the system as a whole.
Not surprising given the length of unsupported shaft and the geometry ratios.
I donāt think this wobble is necessarily lethal to the design. Although vibration on any frequency wonāt help. and this wobble looks like fairly high amplitude in relation to the other major forces.
Anything which smooths out the whole system while encouraging tension inline will likely help.
I donāt know the exact configuration but Iād suppose
Actively smoothing the tracking on the base station will likely help.
Only generating when there is enough tension will likely help
As per my comment from YouTube
I donāt think itās a buckled rod.
looks like a mix of longitudinal tension shock (going up and down the set) combined with a transverse wave (maybe from imbalance in the TRPT or alignment from end to end)
The highest bending on the OTS often looks close to the rotor. I was expecting an end piece material fail from vibration.
Maybe an over sized generator which progressively backs off through the gust when it sees the load risingā¦? might help?
/cb Legend!
Looks like the stabilising line on the generator frame had broken leading to the wobble.
Great video ā¦
Do you have any rough idea the size of gusts so we might work out where the rotor was in terms of itās max torque
As for where the generator torque might have been.
well thatās probably even trickierā¦ too high - at that end moment for sure
My comments suggesting an over-twist due to tension torque imbalance conflict with the /cb report of a buckle. So buckle it is.
Test flight 2020-10-15 Details of self destruction
I reckon this failure needs looking at in real slow motion (around 15 seconds in this video)
Whichever way the fail went itās the same result from roughly the same problem.