Axial Flux PMG Testing for 100W Wind Turbine - William

[W R-P]

Hey everyone.
I've been working on a axial flux permanent magnet DC generator to use on a 100W wind turbine(small I know), to charge 12v batteries in low wind speed areas. Now that it's complete, I'd like to determine the full power curve at different rpms.
So far I've been running it on NO LOAD,using a lathe machine as a prime mover. My results from this were the open circuit voltage and the short circuit current at various rpms- up to about 500rpm. i doubt multiplying the two readings will give me a TRUE value of the power I should expect.
I then tried using a dc bulb as a load, but the only available ones are 9w at 12vdc. If my voltage goes way above 12..it will blow,so that test won't go on for long. No power transducer available either..
My question is is there any simple experiment I can carry out to determine the power output, and what kind of load should i use?

some helpful data
STATOR
1.4mm wire
80 turns
6 coils
star connection, passed on to two block rectifiers
Any input would be appreciated.
William

 

[anorlunda]

You are correct, open circuit voltage times short circuit current is a meaningless quantity.

For your test, I would use a 12 V lead acid car battery. Short term, it can tolerate 9-16V, and it can accept charge at 50 amps or more. That's far above your 100 w design limit.

For maximum current, start with a discharged battery with open circuit voltage of 11 V.

As the battery state changes, you'll get a scattering of V & I measurements and a P value for each. A scatter plot of those versus RPM gives the generator capability.

For safety, enclose the battery in a battery box able to contain acid in case of battery failure.