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Forum Index : Windmills : 12.8A looks like it.....
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KarlJ Guru  Joined: 19/05/2008 Location: AustraliaPosts: 1178 |
Well dad tells me today the wind was well and truly there and yet still only maxing out at 12.8A at 55V which is only 705W for the dual stator F&P was hoping for the big wind to make the 1KW mark. 48V system 1x 80S 2X7C star + 100S 1X14C Delta. 85m cable run in 16mm2 cable. 3.5mm cable droppers from the turbines stators (x2)thus 6 wires in total which are give or take 8m long. Has Gordons doublers too with 680uF 450V caps confident that the turbine is seeing 700rpm as he reckons she was absolutely howling so much in fact that during furling the output was only dropping marginally if at all. Whats next? Ive told dad to flip the brake switches one by one (4of) this will identify if the wiring up to the F&P's is an issue but after that i'm all out of ideas. not unhappy, just dissappointed, great machine in low winds but missing out in the top end. I cant help but think and OZAXFX is the answer...... but certainly not giving up on the F&P's yet. Cheers Karl Luck favours the well prepared |
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GWatPE Senior Member  Joined: 01/09/2006 Location: AustraliaPosts: 2127 |
Hi Karl, I would only see a problem, if the machine was continuously maxed out, producing the 705W, for say 6-12 hours. This would amount to up to 8kWhr, during that period. If the kWhrs was around 4, I would not try and push more numbers, as the wind is not going to give it. It seems like the furling is providing safe protection at upper power levels. I seem to remember that my own mill produced the really big numbers when the furling was not working properly in a storm. Gordon. become more energy aware |
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Gizmo Admin Group  Joined: 05/06/2004 Location: AustraliaPosts: 5124 |
I agree with Gordon, 705 watts is safe, that windmill could do that forever. You could crank up more power, but things are going to break or burn out. Besides, 700 watts is pretty good for a couple of F&P's, I've never seen more than 400 on my dual at my place. The big advantage you mill has IS its low wind power. Thats where its designed to run best and its the low wind watts thats giving you the most benefit. Glenn The best time to plant a tree was twenty years ago, the second best time is right now. JAQ |
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Downwind Guru Joined: 09/09/2009 Location: AustraliaPosts: 2333 |
Karl, If you would like to monitor RPM of the mill we can do that using one of these logger boards i am putting together, it would be a matter of wireless data link back to the battery room and a lcd display if you dont want to run a small old crappy computer of some sort. (Pete ponders where all the win98 onwards laptops end up) You could also send amps and volts wireless to but little point if no way of recording it. Think if you log it, your dad could email you the log files and you could view the data in Perth.(pretty graphs) This is not a sell but an offer if you want to go this way. Watching Gordons mills they furl early but always look in control and a pleasure to be standing under, so for the simple fact he gets great results is a credit to his design. We all know a F&P has its limits and the fact you are getting over 700W is proof of a well designed mill and safe furling. You just have to read fieldlines to see the burn outs by being to greedy and chasing the big figures. I think you should be proud to be hitting the 700w and maintaining it in good wind. Pete. Sometimes it just works |
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| KarlJ Guru Joined: 19/05/2008 Location: AustraliaPosts: 1178 |
Funny thing is it was almost doing that with the furling set at 120mm, now its back at about 75mm. Running a fair couple of hundred rpms higher than before. Dad didnt seem to think it was dangerous but certainly opened his eyes  . and was fairly singing, something I never got to see, he also notes that although the furling obviously slows it down the amps aren't falling off as they did before.
Im guessing here but hypothetically if it were furling at 400rpm and the rpms dropping back to 300rpm then the output would drop significantly whereas if she's furling off at 6-700rpm and dropping back to 5-600rpm then it makes sense that the majic limit of the F&P has been reached?? in that over the 500rpm mark power is not going up anymore but rather just flattening off due to the reactance limiting. Luck favours the well prepared |
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| GWatPE Senior Member Joined: 01/09/2006 Location: AustraliaPosts: 2127 |
Hi Karl, How many kWh were made, and in what time frame. This is the only way to identify if you really have a mill that is missing out on harnessing power. If the windmill did not produce power propotional to the numbers I provided above, then there is no point in persuing it further on a lost power basis. You may only improve the power from wind spikes, and not much overall average power. Having a windmill that now produces optimum power across such a wide windspeed range is the objective. At this point, the system will need to be changed in many ways, to extract more power. The windings are optimum for the 500rpm top end. A rewire and different caps would be required to push more top end power. This may compromize the low end in the bargain. I would leave it electrically, as it aint broke. I would back off the furling, as the rpm you are pushing will place more stress on the rotor, and mill head components. Gordon. PS edit: I see from your post in another thread that the peak strong winds were not all day, and the total for the day was only 4.5kWh. I think little will be gained looking for bigger numbers. become more energy aware |
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| KarlJ Guru Joined: 19/05/2008 Location: AustraliaPosts: 1178 |
going to need another one then a second tower and 2nd turbine looks like the go no point having a heap of $$ tied up in the PVE1200 if I can only punch 700W max through it. the turbine is the cheapest part of the lot, representing only 1/5 of the cost. Thanks Gordon, i'll hit up the old man for more specifics I agree 1 hr of 2000W is not as good as 10Hrs of 300W... I think 2nd time round I can do the pole at 1/2 the price and the hole for the concrete was overkill. Next one will be in the ground about 1m and about 400mm round (thats the size of our post hole digger) i'll do 4 more holes and guy wires upto the top of the fixed portion of the tower and under the fan on the top part of the tower. two winners here 1 I can go up to 10m 2 cheaper Now that No1 is sorted the wind farm will be easier to continue with. Luck favours the well prepared |
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| VK4AYQ Guru Joined: 02/12/2009 Location: AustraliaPosts: 2539 |
Hi Karl Would it be worth trying the neo magnet rotors as reports I have read suggest that they will give an extra output of 30%. I have tried the 100 stator in the lathe and it will do just on 3 amps per phase on a direct delta wiring it reaches that at 650 rpm and then seems to saturate as going to 1000 rpm only makes a few ma more, this is into a 2500 watt heater resistive load using a digital clamp meter to measure amps. The 60 stator came on earlier but was less than 1.5 amps and the 80 stator makes nearly 2 amps. I think the resistance in the wire windings is limiting the current No caps in the circuit or rectifier so the losses of these would have to be added in a working circuit. The windings get warm to touch but not above 70 c and that is without wind effect cooling as in a dynamic situation. The 60 stator got hotter than the 80 over 100 c. Power wire is 15 mtr long its a 30 mtr lead from bunnings cut in half and the matching wires parallel so not much loss there. Based on these figures I am hoping for 1500 watts unless Murphy steps in. I haven't mounted the second rotor yet as am making a four bearing head to cope with the gyroscopic s and high speed wind loading to be on the safe side. I am setting up as direct drive no furling as the rotor goes to 1500 rpm OK lots of volts but less amps only a strong wind will test that out. All the best Bob Foolin Around |
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| Downwind Guru Joined: 09/09/2009 Location: AustraliaPosts: 2333 |
What voltage was you punching out during your tests. What voltage are you aiming to operate at Pete. Sometimes it just works |
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| VK4AYQ Guru Joined: 02/12/2009 Location: AustraliaPosts: 2539 |
Hi Pete It was holding at about 100 volts up to 160 volts when the heater cut out on the thermostat I had a volt meter with bent needle may not be to accurate caused by wrong scale selection, as battery in the digital went flat. I am aiming for 110 volts as I have a DC to DC converter 110 v to 27.5 volts at 13.5 amps, I plan to set up six of them one on each phase on the two stators and switch them in or out to vary the loading on the mill, their rated input is 80 volts to 130 volts cost $38.50 ebay cheaper than I can build them. The other option is to set them to 240 volts and series the output of the two stators more volts less amps I thing on the 240 volt setting they work from 160 to 280 volts, less amps more volts more efficient but loose some of the load control effect of the six phase system. Time will tell, have to increase the efficiency of the FP unit to make it worthwhile as I have a little old 32 volt generator that puts out 60 volts at 16 amps at 1000 rpm, and a 25 volt truck generator that puts out 44 volts at 60 amps at 1200 rpm, they both spin up easy as no PM rotor self excite at around 500 rpm with a bit of nichrome wire to limit field current. Interesting I tried a 12 volt 65 amp generator and got 30 volts at 35 amps out into the battery pack.1500 rpm More to learn on the old stuff I think it has potential if the new high speed blades produce enough torque. Back to the carrot harvest for the next few days. All the best Bob Foolin Around |
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| KarlJ Guru Joined: 19/05/2008 Location: AustraliaPosts: 1178 |
Bob all that foolin around = good figures for us that use the suck it and see method! 100S delta 9A at ~100V is 900W but say the windings are limited to 3A/phase that gives at 55V say 500W star typically 1.7x less thus 290W (for a 100S star) now we've lost a little here to pick up some in the low end by using the 80S 2x7C star call it 250W SO total at ~600 rpm for a 48V system call it 750W less diode loss, less transmission loss, etc etc etc I guess 700W into the batts is looking good. I have considered the NEO conversion but Phill hasnt volunteered his as he had plenty of problems with distortion of the housing and I'm still hoping Bruce will flog me his neo rotor save me mucking around, trying to strengthen it etc. Hows that idea going Bruce? Still for sale, drop it in the post, all I need do is throw it on the back with the 100S and output should come up 200W or so..... Luck favours the well prepared |
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| VK4AYQ Guru Joined: 02/12/2009 Location: AustraliaPosts: 2539 |
Hi Karl There isn't much power at the low end with the 100 but when it comes on it is good, but in my application it needs to be above 400 rpm no caps I did try some caps but wasn't able to get a good result. When in star it only did 1.2 amps per phase as I think there was resistive losses and increased reactance due to more inductors in series looking at the result of that it would produce 370 watts per stator and it dropped off more at high revs. In your machine these losses would be lower due to parrelled windings but I am wondering if there is a interaction between windings in the reconfiguration that is causing losses and heating increase due to the losses only my thoughts. I talked to Bruce but he only said that he had to make a puller to get the rotor off the stator with the neos so there would be much more emf generated across the whole rev range, a work in progress. All the best Bob Foolin Around |
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