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Forum Index : Other Stuff : F&P advice please
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ptrott Newbie  Joined: 08/04/2008 Location: AustraliaPosts: 15 |
Having finally completed my twin F&P centre-drive on one std. shaft, I am now ready for the re-wiring, which brings me to where I need advice. They will be driven by a motor running on bio-fuel, so I have the luxury of running the F&Ps at whatever speed gives optimal efficiency. Research leads me to believe that 1200 RPM is the max. due to the rotors being not balanced, but slower would be more reliable. It will be used to charge a 24 volt battery bank, so I only need about 28 volts or so, but max amps. I have one 1.0mm wire stator, two 0.65mm stators, and two 0.55mm stators to choose from. I assume that two 1.0mm stators would be the best option, but I have been unable to get hold of another one, so the next best option is two 0.65s What would be the best wiring arrangement, and approximate revs required, to get around 28-30 volts, at max amps? Thanks. Cheers, Phill. |
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Downwind Guru  Joined: 09/09/2009 Location: AustraliaPosts: 2333 |
Hi Ptrott, You would want to run the S100 for sure, then what every the bigger size you have next. Im not sure on the 0.55 you quote as there is S100, S80, S60 and all relates to wire size ...series 100 is 1mm, S80 = 0.8mm, S60 = 0.6mm. From my tessting on a test jig you dont get much extra output from about 500 rpm upwards, the core saturates around 500 rpm. What is the motor source and what HP. I hate to say it but you might be better off with a car/truck alternator if you have reasonable HP and able to run a higher rpm. Pete. Sometimes it just works |
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| dwyer Guru Joined: 19/09/2005 Location: AustraliaPosts: 573 |
hi Ptrott Well mate as l do agree with Downwind as l think is best way to go get a long distane Truckie alternator as most have very high amp output have approx 160 amp while excavator or bobcat running around 25 amp as able to pick up from truck wrecking yard as l have 35 amp 24 volt alt (free) to charge 12 x 2volts 220amp deep cyle battery fitted to little Toyota engine that run 3 phase generator for my workshop machine and lights for three years no problems 
Dwyer |
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| ptrott Newbie Joined: 08/04/2008 Location: AustraliaPosts: 15 |
Thanks for the replies. The engine is 3.5HP Lister, max RPM 500. The reason I went for F&P was that there is supposedly significant current used in maintaining the magnetic field automotive alternators, and from what I have read, the permanent magnet versions that are sold ex USA are over-rated, and over priced. Is this correct or not? Would I have to gear it up a lot to get decent output, as truck engines run way over 500RPM. (around 1800 rpm?) I would really like to know exactly how much power is consumed in maintaining the magnetic field, but I have never found any real figures in my research. Regarding the wire size Downwind, I have measured the wire on the stators with a very accurate digital vernier, and the two smaller sizes are 0.55mm and 0.65mm. I will re-measure tomorrow just to be sure. Is the measurement taken with enamel on or off? Cheers. Cheers, Phill. |
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| dwyer Guru Joined: 19/09/2005 Location: AustraliaPosts: 573 |
hi ptrott ------------------------------------------------------------ --------------------- Regarding the wire size Downwind, I have measured the wire on the stators with a very accurate digital vernier, and the two smaller sizes are 0.55mm and 0.65mm. I will re-measure tomorrow just to be sure. Is the measurement taken with enamel on or off--------------------------------------------------------- --------------------- YES you are correct about two smaller size are 0.55mm and 0.65mm as l did have same problem before so l resume that is cheap quantity made by wire manufacture. Nothing wrong with your digital vernier so l let you have some peace of mind 
ian dwyer |
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wind-pirate Senior Member  Joined: 01/02/2007 Location: CanadaPosts: 101 |
Hi Ptrott 1HP = About 740 Watts.. 3.5hp Lister. So about 2000 Watts. 28 volts X 70 Amps = 1960 Watts Thats about the max your Lister will make. The fields "can need" up to 10 Amps. You will have to gear up, So you will have some more loss. So with a good setup you might get back about 50 Amps. 50a X 28 volts charging = 1400 Watts Ron THE Pirate. stealing wind & solar energy is fun |
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| Downwind Guru Joined: 09/09/2009 Location: AustraliaPosts: 2333 |
What sort of lister is it? Is it one with the big cast flywheel or more to a stationary engine style. (Like a brigs and stratton ) I would have thought the field windings power could have been reduced to around 1 amp and not be any where near 10 amp.But im no expert in this area and others might know more than me. Its a matter of how much power you need and your battery size. Pointless having a high output generator and a small battery or demand. Perhaps tell us more of your power needs and intended use. Pete. Sometimes it just works |
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| ptrott Newbie Joined: 08/04/2008 Location: AustraliaPosts: 15 |
Ron's figures are pretty much the reason why I wanted to go with permanent magnets. The Lister has two flywheels, and it weighs about a quarter of a ton. The initial Charge Acceptance Rate of the battery bank will be about 250Amps, (at 40% depth of discharge) reducing as the batteries charge up. This will depend of course on the final size of the bank, but initial calcs. are 1000AHr required. Cheers, Phill. |
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| Downwind Guru Joined: 09/09/2009 Location: AustraliaPosts: 2333 |
Is it something like this you are intending to do. http://www.otherpower.com/listeraxialflux.shtml Pete. Sometimes it just works |
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| ptrott Newbie Joined: 08/04/2008 Location: AustraliaPosts: 15 |
Now that WOULD be sweet Pete. I wonder if I can engineer one of those with my basic machines. I think it might be worth a try Cheers.Cheers, Phill. |
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MacGyver Guru Joined: 12/05/2009 Location: United StatesPosts: 1329 |
Pete & ptrott RE: Pete's Link Shown Above I'm in the middle of my own ax-fx build and I'm turning a HDPE (high-density polyethylene) plate with circles enclosing the magnets, keeping them from wanting to fly off as it spins. The magnets are glued to the iron backing plate (flux-return-path) as well, but even if the glue were to let go, the magnets are each trapped within the HDPE circles. The HDPE disks (2 each) are screwed to the iron backing plates and hubs. Just an extra precaution, plus it makes it easier not to pinch the hell out of your fingers when you place the magnets! Once I'm sure of their polarity, I merely slide them off the plastic into the glue-filled holes. I redesigned my basic chassis and will be throwing up some pictures soon. When I do that, I'll post as much as I can, just to keep everyone up to speed on this. My goal is to build a "no-brainer" ax-fx wind gennie. . . . . . Mac Nothing difficult is ever easy! Perhaps better stated in the words of Morgan Freeman, "Where there is no struggle, there is no progress!" Copeville, Texas |
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KarlJ Guru Joined: 19/05/2008 Location: AustraliaPosts: 1178 |
OK so for the F&P, its efficient enough at 500 rpm that direct drive will be AOK. us the 100S wired in half ie 2x7C in delta and the 60S small wire job will also be AOK in either all parallel or as 7x2C delta. If you were after every watt, perhaps a slight gearing up to 750rpm would also be AOK. in these configs you'll get at least 1000W from my experience which means the lister is just ticking over nicely. In all not a bad combo at all, good luck Karl Luck favours the well prepared |
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| wind-pirate Senior Member Joined: 01/02/2007 Location: CanadaPosts: 101 |
Hi A little more Detail Here is a link to some great Alternator info. It's called Alternator Secrets. You will need PDF to read and open it. Save to your Hard drive when done http://www.otherpower.com/images/scimages/1431/Alternator_Se crets.pdf Copy and Paste to browser. Ron THE Pirate. stealing wind & solar energy is fun |
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| Downwind Guru Joined: 09/09/2009 Location: AustraliaPosts: 2333 |
Hi Ron Your link looks to be broken. This can happen when you dont use the link button above (4th from the left) Besides im a lazy sod and much rather just click the link to access the page rather than the copy paste crap. If the link button dont work for you its because you have script block on and a yellow bar will appear at the top of the page asking you to enable tempary scripting. Answer yes and click the link button again. It should work this time. Give it a go then use the Preview Post button to check it out. Pete. Sometimes it just works |
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| wind-pirate Senior Member Joined: 01/02/2007 Location: CanadaPosts: 101 |
http://www.cecoatings.com/images/misc/homeade%20tig%20welder /Alternator%20Secrets.htm I'll try this one Ron THE Pirate. stealing wind & solar energy is fun |
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| ptrott Newbie Joined: 08/04/2008 Location: AustraliaPosts: 15 |
Great idea. Thanks. Cheers, Phill. |
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| ptrott Newbie Joined: 08/04/2008 Location: AustraliaPosts: 15 |
Karl, are you saying that the core will not saturate at 500 RPM as is the poular belief? Do you mean 1Kw each, or total for the two? Cheers, Phill. |
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| ptrott Newbie Joined: 08/04/2008 Location: AustraliaPosts: 15 |
Sorry, double post somehow??? Cheers, Phill. |
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| Downwind Guru Joined: 09/09/2009 Location: AustraliaPosts: 2333 |
Im not sure on what Karl is baseing his figures on, and might know something i dont. I have a F&P set up on a frame with a electric motor driving it that i can adjust the speed on, i use it for testing out various things. Lately i have been using it for testing of data loggers and from what my logging shows the core starts to saturate at about 500 RPM and you get only a little more as you increase to 750 RPM. To me the extra bit is not worth the extra rpm flogging stuff out for close to nothing gain in power. If you were designing a mill for around 750 rpm i would say you would be a total fool. A motor is different as you can adjust the speed somewhat but i would still design for around the 500 rpm mark with the thought of being able to increase the rpm up some if needed. I dont have a 100s stator anymore so am unable to test this with a logger attached to see if there is any difference with the heaver windings, but i doubt there would be. Pete. Sometimes it just works |
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| Downwind Guru Joined: 09/09/2009 Location: AustraliaPosts: 2333 |
RON, Your link is still broken, and you still havent managed to insert it using the link button above. The forum inserts hidden code into some links if the link button is not used, this is done to protect the forum and all us uses. Please try to master using the link button above and save some trouble with dud links. If you are having trouble than ask. Pete. Sometimes it just works |
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