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Forum Index : Windmills : visual effect of capacitors
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GWatPE Senior Member  Joined: 01/09/2006 Location: AustraliaPosts: 2127 |
The testing of my new arrangement confirms the theory. Here are some graphs of with and without the cap doubler today. firstly without. 
and with new simplified cap doubler 
You can see a bit larger spread in the data set, but it is clear that the cap doubler has reduced the cutin to approx half the rpm. This is not optimized yet, as I just used 6 caps I had on hand. There were no mechanical changes to the windmill, and these readings took approx 10 or so minutes to obtain. The windmill does sound a little different at the low windspeeds, with a slightly lower [loaded and producing output current] rpm. The swish/swish noise that occurred with the essentially unloaded mill has gone. I did not have to use any data manipulation tools, and this was essentially obtained in real time. You will note that the windmill needed to produce approx 44Wh of power to confirm a better output loading curve. The componentry is contained into a small package with the reduced cap count. Gordon. become more energy aware |
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| VK4AYQ Guru  Joined: 02/12/2009 Location: AustraliaPosts: 2539 |
Hi Gordon That is very impressive. All the best Bob Foolin Around |
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Gizmo Admin Group  Joined: 05/06/2004 Location: AustraliaPosts: 5024 |
Looking good Gordon. Anything to reduce the cap count is a big plus. I like the new Piclog graphing, very nice. Glenn The best time to plant a tree was twenty years ago, the second best time is right now. JAQ |
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| GWatPE Senior Member Joined: 01/09/2006 Location: AustraliaPosts: 2127 |
Hi Readers, The spread in the data in the graphs above turns out tobe related to the measurement of rotor rpm. I have some new graphs of without and with caps performance in light wind conditions. The scatter at the higher recorded power levels are the peaks of the wind gusts recorded at the time. These are low wind speed data. [< 5m/s] The power range on the Y-axis is from 0 to 1000W, and the RPM on the X-axis ranges from 0 to 400RPM This is a 3m rotor windmill, with an Axial Flux alternator. First is a measurement on the windmill without a cap doubler. 
you can note the cut in at just over 200rpm, with some scattered data points above cutin. The next is a chart with the cap doubler turned on. 
The caps clearly allow the windmill to produce more power at the lower rpm, with a cutin at around 100 rpm. I have added a yellow line where the output power curve of the windmill would be expected to follow, in comparison to a calculated theoretical. It should be noted that this is not an exact science, but allows an individual windmill to be modified and see how the mods affect its performance. This is not intended to be a scientific windmill performance evaluation tool. There is a fair bit of area under the green line where the windmill without caps would be producing less power at the lower windspeeds. The caps do not hinder performance at higher power levels. The main benefit with this arrangement is that a windmill can be wired with less turns of thicker wire and still produce power at low windspeeds. The thicker, shorter wire results in higher winding efficiency at the high power levels. This will benefit iron cored, and slotless alternator windmills. Gordon. become more energy aware |
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| GWatPE Senior Member Joined: 01/09/2006 Location: AustraliaPosts: 2127 |
The caps have almost concluded now, with the latest phase of my testing. The last change means, that I should be able to further reduce the cap count by half again. this is due do the now polarised effect of the cct, on the caps that are left. This now means that a 3phase cap doubler should only require 3 caps, and 3 3phase bridge rectifiers. The caps should only need a power rating sufficient for the maximum AC ripple, at approx 1/8 of maximum windmill power, with a voltage rating of approx 2x system voltage. I am going fishing to think about this some more, so will test new concepts in about a week or so. Gordon. become more energy aware |
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| VK4AYQ Guru Joined: 02/12/2009 Location: AustraliaPosts: 2539 |
Hi Gordon I look forward to your upgraded system. Enjoy your fishing and keep the grey matter churning. All the best Bob Foolin Around |
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Bub73 Senior Member Joined: 10/12/2009 Location: United StatesPosts: 116 |
I'll look forward to your upgraded system also; sounds like just what my box of ecm motors need. Good luck fishing.. Bob |
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SSW_squall Senior Member Joined: 20/03/2010 Location: AustraliaPosts: 111 |
Hi all, Havn't posted for a weeks or so because i've had a ball-breaker of a week: The wife had an accident and got squashed between a horse that had it's head caught in a rope and the horse float, hurt her knee quite badly and had an operation yesterday to get the cartlige removed that had come off her knee cap. She on the mend now but still incapacitated (nothing to do with a loss of capacitance or otherwise). which in a convient 'Segway' bring me to the point of this post: I reckon Gordon's new 3 phase rectifier + 3 phase voltage doubler could look like this: 
Only 6 Cap's in total!! I was trying to remember where i'd seen this kind of circuit before, then i remembered, the input stage on a computer PSU: The 220V - 110V selection switch just connects the AC side of the bridge rectifier to the midpoint of the capacitor string. 3x for 3 phase and there you have it... AB Einstein: Everything should be made as simple as possible, but not one bit simpler |
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Downwind Guru Joined: 09/09/2009 Location: AustraliaPosts: 2333 |
Nice guess but i think he is down to only 3 capacitors now, and 3 bridge rectifiers. Pete. Sometimes it just works |
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niall1 Senior Member Joined: 20/11/2008 Location: IrelandPosts: 331 |
very very hard to attempt to keep up with the thread...its beginning to rival the bible wonder if its something to do with using the star central (neutral ?) tap connection in some way ... 
niall |
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| GWatPE Senior Member Joined: 01/09/2006 Location: AustraliaPosts: 2127 |
Now that I am using the windmill analyzer software I have written, I will be investigating some more ideas more thorughly. I have some further testing planned for my original 4phase alternator with a cap doubler, in addition to the electronic boost maximizer. I have to confirm the power handling requirements of the components, and some AC aspects accross the full power handling range of a windmill. Gordon. become more energy aware |
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| VK4AYQ Guru Joined: 02/12/2009 Location: AustraliaPosts: 2539 |
Hi Gordon Important, Did you catch any fish or just spend time thinking of some new innovation. We all appreciate you brain so please don't over load it. All the best Bob Foolin Around |
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| GWatPE Senior Member Joined: 01/09/2006 Location: AustraliaPosts: 2127 |
Hi Bob, fishing was great. I met a gentleman [lived to 103] and his claim to long life was to always have a project, so I intend to try and emulate him. Gordon. become more energy aware |
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| VK4AYQ Guru Joined: 02/12/2009 Location: AustraliaPosts: 2539 |
Hi Gordon I agree a friend of mine is still building and flying airplanes at 83 and has a series of projects for the future. If I do all my projects I will need to live for another 100 years so here's hoping. Don't have time to go fishing but that will change later this year as I plan a holiday. All the best Bob Foolin Around |
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| SSW_squall Senior Member Joined: 20/03/2010 Location: AustraliaPosts: 111 |
HI Gordon, How was my guess at the voltage doubler circuit, with reduced capacitors??? I can't think of any way myself to further cut it from 6 -> only 3... AB Einstein: Everything should be made as simple as possible, but not one bit simpler |
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| GWatPE Senior Member Joined: 01/09/2006 Location: AustraliaPosts: 2127 |
I have just run off a plot of part of a days operation of my windmill with the new cap arrangement. This was just under 0.9kWh produced, and the wind was light to medium, as is seen from the power distribution dots. The power was up to 1000W, on the Y-axis, and the RPM was up to 400 on the X-axis. 
This is the power vs windmill rpm. The close relationship between actual power dots and the calculated green line power curve is evident. By using my windmill analyzer, that will soon be available as a software component that will only work at the moment with a new logging kit, I was able to visually see how my windmill worked, and I was then able to build a cap cct to suit. Anyone with a windmill and access to a computer would be able to use the analyser to measure actual windmill performance. The shape of the output curve will determine if the windmill is corrrectly loading, and the windmill analyzer can be used to check the loading following corective measures. I should say that the performance of any windmill change, say for an AxFx windmill, be it blades, stator, air gap, capacitor multiplier, etc can be verified. The real time setup of an electronic MPPT is possible as well. Even a commercial windmill can be analyzed, and corrective measures determined. On this note, The task of working out what to do has become a lot easier now I have my analyzer. I would think that there are many readers with a windmill, who could benefit from this type of tool, and who should make a positive effort to pass on their interest, either to Downwind or me. The amount of interest will determine what is offered. Gordon. become more energy aware |
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| Gizmo Admin Group Joined: 05/06/2004 Location: AustraliaPosts: 5024 |
I'm very interested, and I'm sure lots of us are interested, but we need more real information instead of teasers. Its like saying I have a tool to analyse your cars tyre wear, are you interested? Well yes I am, but is it free or will it cost me something, will I be able to see how it works or are its workings hidden. Is it just instructions and information to build you own, a kit or a complete unit? At the end of the day a windmill analyser is going to be a good bit of kit to have, it will give a true performance profile of your windmill, but we need to know what we need to outlay, and what we get in return. So yes I'm interested. Glenn The best time to plant a tree was twenty years ago, the second best time is right now. JAQ |
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| GWatPE Senior Member Joined: 01/09/2006 Location: AustraliaPosts: 2127 |
Hi Gizmo, I think this says what you are asking, so no the windmill analyzer part is not free. The kit would contain all the components and cct board, and the programmed picaxe chip. The software works fully with the supplied kit hardware and programmed chip. Those users with a piclog, who may wish to access the windmill analyser aspects would need to have the picaxe reprogrammed. The original piclog code will still function as a logging unit with this program. The software knows what hardware is connected, and configures as a logger only with the piclog firmware, and as a windmill analyzer with the windmill analyzer kit hardware. If the supplied picaxe is reprogrammed then the windmill analyzer function would be lost, and a fee for reprogramming would be charged. Existing piclog chips could be reprogrammed to work as well, for a similar fee. At the moment the picaxe code would not be supplied. The Comm port detection and Auto selection, and the user selection of system voltage, maximum system amps, maximum windmill power, and the click select file to view and the zoom within zoom of the logged data, and other additions are free. I am still to add some user personalization touches and the auto creation of prog.cfg and settings.cfg files at startup, if they don't exist. This is additional to the auto creation of logs, excel, and html folders that is already implimented. This will make the moving of the program to a different folder on multiple logger systems more manageable. It can be confusing with which window is which without individual program personalization. I think any readers interested should show their interest, possibly on the what to log thread, or by PM. I will include a note similar to this post on the "just what to log" thread. Gordon. become more energy aware |
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| turnymf Regular Member  Joined: 04/10/2008 Location: AustraliaPosts: 84 |
With only 3 caps, there aren't that many combinations possible I would have a guess at this one 
cheers |
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| niall1 Senior Member Joined: 20/11/2008 Location: IrelandPosts: 331 |
ermmm....with 3 caps and 3 seperate rectifiers this would be kind off like rectifing each phase...then using the caps to series up the dc outputs and bump up the voltage ? 
niall |
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