 Notice. New forum software under development. It's going to miss a few functions and look a bit ugly for a while, but I'm working on it full time now as the old forum was too unstable. Couple days, all good. If you notice any issues, please contact me. |
Forum Index : Windmills : AC Capacitors
| Author | Message | ||||
| leftcliq Regular Member  Joined: 21/07/2012 Location: AustraliaPosts: 51 |
Hi Guys, I have been following the previous threads on adding AC capacitors and I have tried this with good results. I have built the tripler circuit: Doubler and Tripler circuit . Just a alittle confused on which capacitor(s) to use. Currently using 6 x 400uF non polarised caps and I'm thinking I should use the 6 x 200uf Caps. Or should I use a combination of each as in this example: different caps Can anyone shed some quick advice or is there a certain formula that I can follow? I am using a 500w generator. Regards, Dale. |
||||
| VK4AYQ Guru  Joined: 02/12/2009 Location: AustraliaPosts: 2539 |
Hi Dale The size of the caps is related to the number of poles of the alternator, I use Gordon's doubler circuit with good result on my OEM mill, I think it is a 25 pole machine so the frequency is relatively high but when I tried it on mu six pole Chinese machine it didn't work as the frequency was to low so would need to go to much larger caps. By the way they are DC caps not AC caps in the circuit, I tried the tripler circuit but found very little gain over the doubler, i then tried boost modules and found that was better than the tripler but not better than the doubler. All the best Bob Foolin Around |
||||
| leftcliq Regular Member Joined: 21/07/2012 Location: AustraliaPosts: 51 |
Hi Bob, Thanks for your help. I'm using a AFPMG, iron coreless generator. So it is without poles. Just don't ask me how much it cost, had it specially made. The electroytic caps in the circuits act as non polarised caps in series. So you got better results with the doubler than the tripler? What circuit did you use as a boost module? What measurement do you use to determine which one is better? Regards, Dale. |
||||
| VK4AYQ Guru Joined: 02/12/2009 Location: AustraliaPosts: 2539 |
Hi Dale As you correctly say back to back they act as non polarized caps but the overall capacitance is reduced by half due to the series effect. I am not sure why the tripler didn't work well as others had success with it, but I think it was the higher series resistance of the components combined with other circuit losses due to diode losses, while it gave a bit of a gain it wasn't worth the effort in my opinion, maybe on another type of generator it may have been better, i am not sure about your type, you say it has no poles but it must have some or it wouldn't generate. I used a small 4/5 amp boost module I got on ebay isolated by input bridge and output bridge after the main rectifier, it started boosting at 10 volts AC about 12 volts DC and boosted up till the output of the generator at the main rectifier went above battery voltage then due to this path being less resistance it conducted through the main rectifier and by passed the boost module. I spun the generator up in the lathe and watched the two ammeters and the crossover was positive and very controlled, on one of the modules the regulation didn't drop out as the lathe slowed and it kept drawing more current until the magic smoke escaped. On the modules I did use I had to increase the heat sink size with some 38*38*2 alloy angle. I set up the cap doubler and compared outputs at the same RPM as the lathe is constant once it comes up to speed, the doubler was about 1 amp down on the boost module the tripler was cutting in a bit earlier but as 1.5 amps down on current. The boost module cut in earlier at above 7 volts AC from memory but only gave a few milliamps so not worth worrying about. All this was with my generator and yours could be quite different. The advantage I found with the boost module is it works on the DC not the AC so it is consistent across a number of generators I tried it on whereas the doubler and tripler work on AC so the higher the number of poles the higher the frequency and the higher the efficiency for the given capacitance. All the best Bob Foolin Around |
||||
Tinker Guru Joined: 07/11/2007 Location: AustraliaPosts: 1904 |
Hi Dale, The above has me curious, is there a website that explains more about these? I tried looking it up in wikipedia but hit a blank there. Never too old to learn something new  Klaus |
||||
| leftcliq Regular Member Joined: 21/07/2012 Location: AustraliaPosts: 51 |
Hi, I bought these from AFPMG . They made one up for based on what I required. Very professional to deal with. REgards, Dale. |
||||
| Purpc Newbie  Joined: 14/11/2012 Location: PortugalPosts: 1 |
Someone can hep me make the choise for using gordons cap mod I have an axial flux iron less 9coils/ 12 poles 3 phase, with a cut in 24v@/140rpm, wound with 84 / 1,5mm diam , for a vawt, can someone advise Witch circuit should i bild and the cap size/volt. |
||||
norcold Guru Joined: 06/02/2011 Location: AustraliaPosts: 670 |
Bob, Try Gordons quad cap(quadrupler) on your original Chinese turbine on 48v, I believe you`ll be pleasantly surprised. I used just 2200uf 50v caps that I had hanging around, cheap as chips. WhenIgetroundtoit, I`ll try Phils Al blades on orig chinese turbine, bigger dia with quad caps should equate to lower wind speed start up. The quad caps seem to offset the higher speed that particular turbine needs to get charging allowing it to charge at half speed and even lower. We come from the land downunder. Vic |
||||
ing.sohaib Newbie Joined: 24/05/2015 Location: CanadaPosts: 1 |
Hi Dale, I have been looking for a simpler solution to this issue and have been unable to find any up till now. I think we can only test these capacitors by actually incorporating them in the loop to try and test the response. To be honest, I think you'd be alright with using 200uF capacitors but I'm not sure about the number of capacitors. If you've found some literature on this, please let me know. Regards, Sohaib |
||||
| VK4AYQ Guru Joined: 02/12/2009 Location: AustraliaPosts: 2539 |
H Leftcliq I have used boost modules to get the same effect and because they are voltage driven they are not frequency sensitive as Caps are I have several working away after 3 years use and still going strong and reasonably priced compared to a heap of caps I see there is a new addition to the ebay listings and it is capable of 600 watts I haven't tried this one but have ordered one to give a try. http://www.ebay.com.au/itm/141014719202?_trksid=p2055119.m1438.l2649&ssPageName=STRK%3AMEBIDX%3AIT All I do is set the output voltage 1 volt above float voltage and isolate with an input bridge and output bridge this prevents an overcharge on the batteries, it is connected after the 3 phase rectifier. You will need some fan cooling of the module an old computer fan would do the trick I think. I am going to try some 12 volt panels I have and boost to 24 volt, just to see if it works OK. Have a look at some of my earlier posts for a more concise explanation, keep in mind that these experiments where conducted with 150 watt units. All the best Bob Foolin Around |
||||
 Print this page |
