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Forum Index : Windmills : Question? 48v from F&P
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fillm Guru  Joined: 10/02/2007 Location: AustraliaPosts: 730 |
To All , As I have almost completed my first mill mechanicaly , I am now getting into the elect side and I am wanting to know does anyone out there run a 48V system ? , or can give me advice on how to reconfigure the stator to achieve this ... Why I am trying to get to 48V is to be able to connect the wind gen through a battery bank into a latronics PVE 1200 Grid tie inverter. The other opt I have thought of is a 24V - 48V convertor but have not heard or seen of such a beast..I have posted pictures of the mill a couple of weeks ago [ my dual stator & seeley ] my aim is to get 48v out of this mill ..... Any suggestions from all the elect gururs out there would be appreciated .... ---- Regards .. Phill..----- PhillM ...Oz Wind Engineering..Wind Turbine Kits 500W - 5000W ~ F&P Dual Kits ~ GOE222Blades- Voltage Control Parts ------- Tower kits |
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vasi Guru Joined: 23/03/2007 Location: RomaniaPosts: 1697 |
Glenn, 2 groups, 8 poles (old stator, old rotor)? I started from 7 groups 2 poles . Is that the configuration for 12 volt system? Fillm, no charging until very strong winds? Is ok for you? And I think is a slow charging, low amps. Hobbit name: Togo Toadfoot of Frogmorton Elvish name: Mablung Miriel Beyound Arduino Lang |
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| fillm Guru Joined: 10/02/2007 Location: AustraliaPosts: 730 |
Hi vasi , Was thinking i would need the mill to run fast to get 48v , but is there a configuration that would better suit 48v.? I have just been searching on the net for 24v to 48v converters and they are available but at what cost i dont know. May be that is the more logical way to go as the f&p can get to 24 v easy but with a 3.1 mtr dia prop I might have to start triming the tips to even get 24v , as I am starting to configure I was hoping some one has been down the similar path.... ----- Thanks... Phill...------ PhillM ...Oz Wind Engineering..Wind Turbine Kits 500W - 5000W ~ F&P Dual Kits ~ GOE222Blades- Voltage Control Parts ------- Tower kits |
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Gill Senior Member  Joined: 11/11/2006 Location: AustraliaPosts: 669 |
G'day fillm, Your wind gen is a dual F&P, so what's to stop you connecting them in series? Each is capable of 24v, the only concern is synchronisation. If you seriesed them after rectification you'd have even less to worry about. 
no losses from a boost converter, normal cut-in and ruing speeds. Saves money too. Well that's the road I'd be going down. was working fine... til the smoke got out. Cheers Gill _Cairns, FNQ |
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| vasi Guru Joined: 23/03/2007 Location: RomaniaPosts: 1697 |
One shaft, two rotors same type, and stators and rotors same position, so no problem with synchronisation. Good idea Gill. Is about 7 groups 2 poles configuration? Hobbit name: Togo Toadfoot of Frogmorton Elvish name: Mablung Miriel Beyound Arduino Lang |
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Trev Guru Joined: 15/07/2006 Location: AustraliaPosts: 676 |
Hi Phill, Some raw data that I have worked out from my lathe. Using 80 series motor. RPM........open circuit volts dc ...........7 pole delta..7 pole star..2 pole delta..2 pole star 65.........12.6.....22.7.....3.1.....5.7 180........36.4.....64.4.....9.7.....17.3 200........39.6.....69.9.....10.4.....18.7 235........47.8.....84.0.....12.7.....22.7 330........65.7.....115.1.....17.7.....31.3 550........110.1.....???.....30.0.....52.8 700........???.....???.....38.8.....68.0 910........???.....???.....49.2.....85.4 If you can derive enough voltage from one motor and are able to run 2 separate lots of wires from each motor, then in light winds you could get power from one while the other is switched off... just freewhelling. But when the wind is strong enough you can switch on the 2nd motor to charge also. Trev @ drivebynature.com |
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| Gill Senior Member Joined: 11/11/2006 Location: AustraliaPosts: 669 |
Yes Vasi, that's what I was thinking. But... But looking at Trev's figures, now I'd be more inclined to go for the 7 pole star for my location due to its usual light and turbulent nature. IF i wanted 48V. So may wonderful choices.  was working fine... til the smoke got out. Cheers Gill _Cairns, FNQ |
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| fillm Guru Joined: 10/02/2007 Location: AustraliaPosts: 730 |
Thankyou Trevor & Gill, I remember when I visited you Trevor you explained the 7 pole config to me but I am very hazey on how to wire it . From your figures 7p star looks good for getting volts up quickly and 7p delta for when power is avail from wind strength . Could it be wired as 7 pole star/delta and use eccoin's switch to change between str / dlt . Have you a sketch on the 7 pole.? I had considered series the two after rectifing would it be possible to join a + & - from bridge rec and double the output volts in DC , it seems simple but would you need 3 Phase bridge rec's on both stators so the output is the same ? -----...Regards...Phill...----- PS .. Trev I did a bit of searching though the posts and found Glen's diag's of 14 & 7 pole from 6/1/06 and shows the star and delta you explained I think . Will have to try and work out series/parrell and how to switch ... Any ideas muchly appreciated ....Phill.... PhillM ...Oz Wind Engineering..Wind Turbine Kits 500W - 5000W ~ F&P Dual Kits ~ GOE222Blades- Voltage Control Parts ------- Tower kits |
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| Trev Guru Joined: 15/07/2006 Location: AustraliaPosts: 676 |
Hi Phill, To do the star/delta switching you need to have ac wires down the pole from the delta formation. One end you take power from all the time, and the other end can either take power (delta) or be connected together (star). It is also possible to series the dc output in low wind and parrallel the dc output in higher wind at the bottom of the tower. Yes you do need to rectify first. Too many choices hey!!!!! Here is a pic of the simplest way to make 7 pole delta. There are a few wires missing, but I'm sure you can work it out. You should have a total of 12 wires out. The 2 halves can be parralleled, by phase, reducing the number of wires. 
Trev @ drivebynature.com |
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| fillm Guru Joined: 10/02/2007 Location: AustraliaPosts: 730 |
Hi Trev, Thanks , I printed of the diag from 6/1/06 and took it home and scratched my head for a while as it was not anything like I remembered about spliting the stator into two halves anyway it shows the same as a 2 pole but said 7 pole ... I sat down with a busted stator and came up with exactly like you have shown . I thought I would go with the whole stator in star or delta and that would give 6 wires out for one stator and 12 for two if bringing AC down the pole, and switching from star to delta at the base. Whats your thoughts on two stators 7 pole delta into 2 x 3phase bridge recs that are have the DC terminals in + - < joined > + - to get the amps up at 48V at lower RPM for big blades ? ---- .. Thanks for your input .. Regards . Phill.. ----- PhillM ...Oz Wind Engineering..Wind Turbine Kits 500W - 5000W ~ F&P Dual Kits ~ GOE222Blades- Voltage Control Parts ------- Tower kits |
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| Trev Guru Joined: 15/07/2006 Location: AustraliaPosts: 676 |
Phill, Its all a matter of ...... 1) How much wind you have 2) How big are your blades 3) How much RPM you can get 4) What voltage you must reach .......all in combination. Mostly its about setting up for your situation. My White Pointer double is wired in 7 pole delta, each motor rectified seperately, then dc parralleled and only 2 wires through the slip rings & down the pole. My blades are 2.9m diameter. The wind here is usually quite tame, usually not more than 10 - 12 m/hr. Rare accasions I have seen it up to 15 m/hr. Once it got up to 20 m/hr. I get more power per day (12v system) from the 7 pole delta than I would if I had it wired in 2 pole, I just don't get the wind to produce the RPM. That is the RPM required for 2 pole does not happen often enough, long enough. Just take a guess, put it up and watch what happens. If you used the 7 pole delta, rectified at the top, but had 4 wires (pos & neg off each motor separate) down the pole, you could connect in series in low wind and have 48v or so from about 150 RPM, but above 300 RPM you could change to parrallel and double the amps. But then if you can't get to 300 + RPM, then it would be little difference to just using 7 pole star, rectifying and parralleling at the top, and having only 2 wires down the pole. My thoughts on using the whole stator, the volts are likely to be way too high. But then it depends on the available wind and produced RPM. Just put something up and tell us what results you get. Attempt to work out what RPM you are getting. If you know what wind speed you have, it helps in finding answers to the equation. No such thing as 'Good Luck '. "hav a go". Trev @ drivebynature.com |
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