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Forum Index : Windmills : F&P rewire question
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| SteveL Newbie  Joined: 27/03/2013 Location: AustraliaPosts: 5 |
Hi Everyone, I have recently built a VAWT usung 3x 205ltr drums. Spinning well producing high torque at low RPM's. With one stator factory wiring (1x12C) i'm getting a maximum of 32 volts in strong winds and 25 volts in average winds. The issue is that the offgrid system is 48 volts so I was considering mounting a second stator and wiring in series (i'm guessing 1x24C). can this be done by removng the bridge at the start of the windings of the second stator and connecting the first stator to this point. If anyone can help I would appreciate it! Thanks, stephen. |
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Madness Guru  Joined: 08/10/2011 Location: AustraliaPosts: 2498 |
I would be looking at a belt drive or gearbox to increase the RPM of the generator. Even 2 in series is going to get you only 50 V in a average wind which is not enough. There are only 10 types of people in the world: those who understand binary, and those who don't. |
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Gizmo Admin Group  Joined: 05/06/2004 Location: AustraliaPosts: 5078 |
Madness is right, you have a good case for a step up drive system. The VAWT type sounds like a savonius, and this would have the torque to drive a gearbox, chain drive, etc, to get a higher rpm. You can wire two F&P's in series without using rectifiers, but its not easy. See the phases need to be pretty perfectly matched, or it will cancel out and you could end up with less output, or none at all. Its a lot easier to have 3 phase rectifiers on each stator, and then connect the DC outputs in series. Glenn The best time to plant a tree was twenty years ago, the second best time is right now. JAQ |
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fillm Guru Joined: 10/02/2007 Location: AustraliaPosts: 730 |
Electricial gearing is a lot better than mechanical , you have a number of options , the easiest is to use 60 series stators unmodified star ( low RPMs High Volts ) from memory a unmodified 60 will cut in at 60rpm for 48V , the second is you can series the outputs on the dc side of the bridge recs which is an easy way to double voltage so 2 60S seriesd on the DC will cut in at 30rpm , you can use a cap doubler or you can use electronic voltage doublers. I would make mechanical my last option for the best efficiency . PhillM ...Oz Wind Engineering..Wind Turbine Kits 500W - 5000W ~ F&P Dual Kits ~ GOE222Blades- Voltage Control Parts ------- Tower kits |
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| SteveL Newbie Joined: 27/03/2013 Location: AustraliaPosts: 5 |
Thanks everyone, Hi Fillm, I tried the 60 and got the results you suggested. Moderate wind I now have 60 to 65 volts and should work ok. The other stator I had was a 8 mm winding. Amazing the difference!! If I was to put the DC side of the bridge recs in series, and each phase was approximately 20 volts would this equate to 60 volts as there are 3 phases? The reason I ask is that I quoted 25 volts in moderate winds therefore if the DC output was in series wouldn't this equate to 75 volts. Just trying to get my head around this!! The second question I have is: can I use the same charge regulator (for the VAWT) as the solar panels are currently using. I have 1.5 KW of Panels and a PL 40 Plasmatronics charge regulator, therefore I feel there is plenty of capacity left. Thanks Stephen. |
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Downwind Guru Joined: 09/09/2009 Location: AustraliaPosts: 2333 |
Phill is correct, anything less than a 1:1 ratio of mill rpm to alternator in a small scale mill (not industrial) is a non efficient mill, and never will be with a increased ratio drive system, It might be ok for hydro systems where mass torque is available, but not for wind energy. The whole theory behind a good mill is to best match average rpm of the mill, to supply the voltage output required on a 1:1 ratio. If you have say 2 x series 60 stators and 3 phase rectify the outputs, to now you have 2 x DC supplies, which gives 2 options. 1) you series connect the outputs and get 2x voltage and 1 x the current. 2) you parallel connect the outputs and get 1x voltage and 2 x the current. No matter what you choose, having 2 stators will double the load on the mill, so can the design support 2 stators. Sometimes it just works |
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| fillm Guru Joined: 10/02/2007 Location: AustraliaPosts: 730 |
You Can NOT directly feed a wind mill into a PL40 , but, you have the best Battery Management control that money can buy ... You can use the PL to switch a dump load as well as control the solar . A PL40 can only switch 6A on the load terminal so you will need to use a relay to the Dump. On Plasmatronics Site there is wind sheet 1 and 2 as a down load , by using a PLS2 and shunt you can also see the amps and Ahr http://www.plasmatronics.com.au/downloads/PLWINDsheet2.pdf Down load the full manual and have a ggood read , they are a very powerful control with loads and loads of well thought out options PhillM ...Oz Wind Engineering..Wind Turbine Kits 500W - 5000W ~ F&P Dual Kits ~ GOE222Blades- Voltage Control Parts ------- Tower kits |
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| SteveL Newbie Joined: 27/03/2013 Location: AustraliaPosts: 5 |
Thanks Phill, I have downloaded the page and yes the infomation helps. What happens if the input voltage gets up to arround 100 volts or so as I would suspect in high winds as I now have 48 volts plus in moderate winds thanks to the 60 series stator. Can the voltage be to high and how does the PL 40 cope with this. The other question is: could I use a wall mounted bathroom heater as a dump load. Thanks, Stephen. |
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| fillm Guru Joined: 10/02/2007 Location: AustraliaPosts: 730 |
Steve, As I said previous , you CAN NOT connect a wind turbine directly to a PL40 you will BLOW IT UP and that will Cost $$$. The wind gets connected to the battery and the PL dumps from the batttery as shown in the Download Wind Sheet 2 , there is another method that can switch the turbine to resistive loading but requires another 3 phase rec and a SSR . I doubt you will be able to use a bathroom heater with out modification. PhillM ...Oz Wind Engineering..Wind Turbine Kits 500W - 5000W ~ F&P Dual Kits ~ GOE222Blades- Voltage Control Parts ------- Tower kits |
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