Author Topic: F&P stators operate best with a constant current output  (Read 1880 times)

0 Members and 1 Guest are viewing this topic.

DaveP68

  • Newbie
  • *
  • Posts: 30
  • Country: nz
Re: F&P stators operate best with a constant current output
« Reply #27 on: November 07, 2017, 04:36:36 PM »
I've watched this video in detail and logged the data points to produce the graph below for Power/RPM vs wind speed m/s.
10906-0

I think you could be onto something re the turbulent wind conditions at that site as the power/rpm are up and down with respect to wind speed.

There are probably other factors that come into play too.
There are realities that if you do not accept, will lead to frustration because you will be spending time on wrong assumptions and the results cannot follow!

SparWeb

  • SuperHero Member
  • ******
  • Posts: 3338
  • Country: ca
    • Wind Turbine Project Field Notes
Re: F&P stators operate best with a constant current output
« Reply #28 on: November 08, 2017, 11:15:14 PM »
Good work. 
I see a reasonable correlation.  Is that from turbine 1 or 2?

If you're interested...
Since you've got the numbers in excel, you can plot a "Scatter chart" instead, with RPM as the X and Power as the Y axes.
Don't try to draw a line through the data - just plot the points
That way you can see if the scatter looks like the scatter plot he was showing on his computer screen in his video.
If it looks different, then we will have caught something else fishy.
No one believes the theory except the one who developed it.  Everyone believes the experiment except the one who ran it.

System spec: 135w BP multicrystalline panels, regulated by Xantrex C40, DIY 8ft diameter wind turbine, regulated by Tri-Star TS60, 800AH x 24V AGM Battery, Xantrex SW4024

DaveP68

  • Newbie
  • *
  • Posts: 30
  • Country: nz
Re: F&P stators operate best with a constant current output
« Reply #29 on: November 12, 2017, 04:19:16 PM »
The data in the first graph is only from turbine 1 with the GOE 222 blade prop.

There was only limited data available from turbine 2 and also it's went into a PWM type dump load state at times with not much output being monitored going to charge batteries. Monitoring system seem to be only loading what is charging batteries from what I can work out.

Here is the scatter chart power output vs RPM you requested.
10918-0

Looks similar to logging graph in the video but with bottom end data missing.

I consider most of the data in the video a bit miss leading, as the general conciseness is the GOE 222 blades are understood to have a TSR of 5 to 6 (maybe closer to 5). The TSR numbers when calculated from wind speed vs RPM data, range from 7.8 minimum all the way up to 11.86! That higher number would put it at 2x times the optimum and the Cp would be very low at that end of the curve.

Going by the calculations illustrated earlier in this very same topic with a Cp of 0.3 or even say 0.4 & with PMA at 50% efficiency I can't get a power output any higher than 211 W at 6 m/s of wind.

In the video it shows around 1 kW of power output being produced at 6 m/s of wind speed.

Have a careful look for yourself going second by second as the data points for power/RPM/wind speed change. Those parts on the video account for about 3 min out of 8:40 total.

I've added 3 m/s per second to the wind speed readings and the numbers then start to stack up as real world. TSR numbers come down to more realistic amount as well.
There are realities that if you do not accept, will lead to frustration because you will be spending time on wrong assumptions and the results cannot follow!

SparWeb

  • SuperHero Member
  • ******
  • Posts: 3338
  • Country: ca
    • Wind Turbine Project Field Notes
Re: F&P stators operate best with a constant current output
« Reply #30 on: November 15, 2017, 12:31:18 PM »
Quote
...I consider most of the data in the video a bit miss leading...

Yeah, sorry, just about everything on YT is like that.  Enough numbers to look intelligent, not enough facts to prove anything...
Fun to watch though! 

The folks who do this stuff scientifically for a living (NREL, and their kin) spend a lot of time making sure their equipment is set up in a way that all the data points line up.
Many of their long-term test reports are very detailed, and actually well written.  Enough that a layperson with a passing knowledge of wind turbines would understand them.
No one believes the theory except the one who developed it.  Everyone believes the experiment except the one who ran it.

System spec: 135w BP multicrystalline panels, regulated by Xantrex C40, DIY 8ft diameter wind turbine, regulated by Tri-Star TS60, 800AH x 24V AGM Battery, Xantrex SW4024