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Forum Index : Windmills : F&P@PE
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Gizmo Admin Group  Joined: 05/06/2004 Location: AustraliaPosts: 5078 |
I've been trying to find the post where someone actually measured the efficiency of the F&P. Buggered if I can see find it. I do remember it was something over 80% efficient at converting the mechanical energy into electrical energy. I'm not sure on the efficiency of the Axial flux machine, I imagine it would be higher than the F&P, but cant be driven at its full potential due to heating problems. Glenn The best time to plant a tree was twenty years ago, the second best time is right now. JAQ |
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| Dinges Senior Member  Joined: 04/01/2008 Location: AlbaniaPosts: 510 |
It gets worse... I applied for the job of Nuclear Safety Engineer there once... Figured the best way to make sure ElectraBel didn't mess up was to take matters in my own hands...  . But at least I've got iodine pills so if something happens to that plant, I'll take a pill and be allright.  With the prevailing south-westerly winds any nuclear debris of a nuclear incident is bound to float over the border, straight in/over my village. I don't think the powerplant of Doel is more than 2 km from the border.
Nice city. Give her my regards. (or, 'doe haar de groeten') Oops... Sorry Jarbar, my memory wasn't that good. But I'll never forget it now.
Jarbar, I'm proud to be allowed to call myself a member of this forum. Small yet highly innovative forum with some highly competent members, people that are not afraid to try out new things and people that are open to criticism without taking it the wrong way. Laid back feel to the board. Simply a pleasure to participate. Dom, not glowing (yet). Besides, if I take the iodine pills all should be fine. The powerplant of Doel basically powers the entire city of Antwerp, industrial zone and surrounding area. I regularly visit Brasschaat, it's nearby and I have family living there (and in Schoten and Kapellen, also in the same area). Gordon, sorry, my mistake, I should've read better. But there's still a major difference, a factor 2.3. So, if the AF would put out 100W the F&P would put out 43W (assuming identical blade efficiency). That's only 43% efficient... the rest would be absorbed as heat in the F&P stator ?(*if* the blades work as efficiently as those of the axial flux). If so, that amount of heat should be very noticeable. If there is little heat, it suggests a blade (or blade matching) issue. You could do a De Prony brake test to determine efficiency of the bare generator. Then, by installing the blades and having it fly, you could measure electrical output and compare that with the power available in the wind. If you know total mechanical windpower input, electrical output and generator efficiency, you could work out blade efficiency. Also, it's not just a matter of the generator itself being good and the blades themselves being good; if the blades and generator aren't matched to eachother the resulting performance will be sub-optimal. Nothing that a bit of measuring won't solve. And I see you're pretty well set out to do just that. Looking forward to updates on the mill. |
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| Jarbar Senior Member Joined: 03/02/2008 Location: AustraliaPosts: 224 |
Hi Phill, again buried in this site is info relating to losses of twisting poles versus linnishing radius's.Where that is I,m not sure at the moment but will try to find it for you.But I recollect that considerably less losses were evident from the twisting process.With the tool I managed in less than 2 mins to twist the 42 poles on a stator.This gave approx 10 deg of twist on the first rotation as the tool would impinge on the adjacent poles.But having been around once and achieved 10 deg another 10 deg is possible as impingement is lessened by the already previous twisting.I intend to try a second rotation to 20 deg in the next day or so.The reason being to just see what more reduction in start up tourqe is evident.You will need to machine on that beautiful new lathe the increased OD of the stator as twisting slightly raises 2 diagonal corners of the poles.The twisting action feels a bit like a trip to the Chiropracter.An initial crack as the windings move then a relaxation as the laminations submit.By using the tool equal pressure is applied to pole and it,s alignment more assured.Versus using a spanner or some such that applies uneven tourqe to pole and can consequently move pole sideways out of alignment and potentially damage the end of it as well.As for losses of an electrical kind you are asking the wrong person.To date what little energy my health has given me has primarily been directed at reducing mechanical losses encountered by VAWT,s.As discussed earlier this year on the forum.Any way with a tool and your skill twisting and new lathe is very easy and effective solution. Anthony. "Creativity is detirmined by the way you hold your tounge".My Father "Your generation will have to correct the problems made by mine".My Grandfather. |
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GWatPE Senior Member Joined: 01/09/2006 Location: AustraliaPosts: 2127 |
Hi readers, Re the efficiency. I expect the losses be pretty equally distributed between the stator and the blades. At this power level I expect probably 70% efficiency of the F&P alternator and the wooden blades may be only 70% as efficient as the Lacota blades. I have twisted the poles of the 100S stator to reduce the cogging, and the results are looking good. I am at about 5 degrees so far. I will compare and record this before proceeding. This does involve complete lowering and dismantling of the mill head. The stator will be going back in delta. When I finish restoring the wooden blades I expect to improve their performance as well. Will keep posting updates. Gordon. PS update. The twisted pole mod has made a huge difference to the cogging and associated noise. Not quite enough wind yet. No wind yesterday either. The mill is also wired in delta now. Wind is forcast. Waiting in earnest. become more energy aware |
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| GWatPE Senior Member Joined: 01/09/2006 Location: AustraliaPosts: 2127 |
Hi Dom, The brushes are large blocks of copper/carbon, approx 16mm x 16mm x 9mm. Hi jarbar, The pole finger ends on my 100S stator had no step at the outer edge. I used a lever to bend one way on one side and then repeated for the other side. I just dressed the pole ends with a file and then a feeler gauge check all round. I have not measured the twist angle. My objective is to only twist enough to reduce the cogging noise to acceptable levels. Hi dinges, I have no mechanism for bench testing. I had looked at a drill press. not yet. The blades need quite a bit of work. The airfoil is pretty good, but the trailing edge could be improved. I will need to set up a dam against the front surface and add a carbonfibre/microfibre blend strip and then re finish. I am an advocate for sharp trailing edges. Hi Gizmo, I believe the efficiency was measure by DR Chalko. I have not looked for the post. There was a link to a research paper. I seem to remember 82% came up. I remember this was a heavily modified stator and high rpm. The full potential of a machine is a contentious point. I believe an axial flux topology is good for windmills. The lack of iron has real benefit. I suspect that scaling up to commercial MW size would present a challenge. I would say that heating is purely related to overdriving and overloading and lack of adequate mechanical protection schemes for wind peaks. Hi oztules, The machine I would consider to be over driven, even for the wind conditions I am trying to match. The furling mechanism is similar to my original mill, where furling starts at 7.5m/s and is max at 12m/s. I have no desire to peak the max power at this stage. The 3m blades have enormous potential if pushed to say 15m/s and rewiring and using a maximiser. I will have to check the max rpm. For a tsr of 6 the rpm should be close to 350 at a 10m/s windspeed. I doubt the mill will achieve the 500W that in theory should be available with a 30% efficient blade and 50% efficient alternator. Hi phil, The pole twisting is not reversable. The stator does require pole face dressing. Reversal would change the air gap. I hope this answers most questions, Gordon. become more energy aware |
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| GWatPE Senior Member Joined: 01/09/2006 Location: AustraliaPosts: 2127 |
Some data for higher windspeeds confirms my suspicions re power outputs. Today we had up to 15m/s winds. The rotor exceeded 300 rpm. This was in delta configuration directly into 24Vnom battery at SOC level 26V. I used a maximum recording amp meter on both the F&P and my axial flux machine. I did not have time to set up continuous logging. The F&P maxed at 10.5A and the axial flux at 12.5A during the test period. The 3m blades had no difficulty overdriving the F&P. The machine I would classify as dangerous as the mill continues to speed up even though no extra current is produced and is furling. This was a 270W power level. The mill was partially furling, 20-60%. Compared to 325W for axial flux and 40-80% furled. I was surprised that the F&P machine with a 3m rotor still did not outperform the 2m rotor axial flux unit, even at the higher power levels. I have some decisions to make and a priority is to slow the rotor during peak winds. I will be investigating a star configuration again and then with a cut down set of the same blades and then possibly a modification of tail boom geometry to increase the furling rate. The power level is sufficient. I will attempt to tame the top end and hopefully limit the over driving. I do not intend to stack stators. Reducing the TSR may be all that is needed! An interesting factor was no apparent reduction in output with twisting of the pole fingers. Gordon. become more energy aware |
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| Jarbar Senior Member Joined: 03/02/2008 Location: AustraliaPosts: 224 |
Hello Gordon ,Phil and others, I am about to rewire my first F&P 80 series in star as per photos.I think this is the best configuration for my slow but tourqey VAWT.In your modifications where are the bridge rectifiers mounted.And what size cable is needed to run down to ground.I know this sounds very basic but my endevours to find this info have only turned up the photo of the Dick Smith rectifiers under alternator conversion.And if dual rotors are being used do they both run through the same rectifiers.As you can guess my electrical comprehension is somewhat lacking.Photos would help. Anthony.  "Creativity is detirmined by the way you hold your tounge".My Father "Your generation will have to correct the problems made by mine".My Grandfather. |
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| Gizmo Admin Group Joined: 05/06/2004 Location: AustraliaPosts: 5078 |
Hi Gordon. As I said earlier, the 3 meter blade is too big for a single unmodified F&P. While the turbine may go faster, the F&P is at its limit due to copper resistance, you just cant pass any more current down that 1mm copper wire. The F&P is a tough little bugger, it will get hot when over driven, but the heat is radiated out from those exposed windings and not burn out the stator. It can be over driven all day with no damage. Now if it were a axial machine, the coils would start to burn, the stator warp, the magnets would tear it apart and in the process loose their strength. I think to truly compare the two types, they need to have the same turbine. And maybe costs should come into it as well, I know the axials are very expensive compared to a scrounged F&P motor. Its good to see your doing the research one step at a time. I would suggest you try splitting the 100S into two, break the connection at the opposite side and end up with two stars (or deltas) with 7 coils(poles) per phase instead of the current 14 coils per phase. This will double the current capability of the stator and give more current in higher winds. Its not until you reconfigure the winding that you start to match the F&P to the turbine. 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, If I start to rewire, mod the stator, this will affect the cutin again and the rotor speed will have to increase. I am not trying to get any more current. The current 300W, will max out what I can put back to the grid. I am satisfied that the twisted pole fingers reduce the cogging enough to allow me to start reducing the rotor size. This may be enough. The issues I see with axial flux machines relate to greed. There is some conception by some designers that a machine rating is where the total efficiency drops to 50%. Unfortunately in an axial flux design this means that the same amount of rated output power is dissipated in the windings. There is no way the stator can dissipate this heat without failing in the process with this type of rating. I can assure you that in my design that 450W is not dissipated in the windings at my rated max electrical output. I post this photo from another thread. 
It would seem that a F&P machine is rated by the manufacturer at 165W only for this model, but we push the stators to 300W. I would suspect that there may be a particular wind energy level where the efficiency approaches levels described by Dr Chalko, but at the extremes that occur with wind energy and the inability to load precisely with so many variables that the efficiency probably is around the 50% level for most windmill installations. I am in the process of restoring the 3m wooden blade set, so testing with these will be on hold for a while. I hope to continue with a cut down, 2.4m set with a lower tsr. I do not think the cost of a scrounged alternator from the tip is a true reflection of the real cost. On that basis, my axial flux cost me nothing either, as it was recovered from a similar fate. For me there is satisfaction from personal input and the final product serving a useful purpose when finished. At the end of the day I hope to have a second machine that will not annoy the neighbours, is not a liability with bits flying off over time, and can survive the weather conditions where I live, unaided, and as a bonus can produce some useful power in a wide range of winds. Hi jarbar, windings fom different stators should be separately rectified. It is unlikely that they would be exactly in phase. The windings from the same stator should be in phase, if the rewire is performed correctly. The wire size depends on the length of wire run to the load and the system voltage and the current. On my system, 24V @ 10A @ 10m I used 2.5mm conductors If the system voltage is double for the same amount of power then you could drop to 1.5mm for roughly the same % wiring loss. I distance is doubled, then go to 4mm. If outside these values, see an electrician and do a wire sizing for your specifics. Diversion load effectiveness is affected by distance from the windmill and wiring sizing. Gordon. become more energy aware |
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Gill Senior Member Joined: 11/11/2006 Location: AustraliaPosts: 669 |
Gordon, I note most (80Series) F&P Smartdrive are rated at 165Watts, from the 5kg washer through to the 7.5kg machine which I think is odd as whilst all machines use the same motor, the load of wet washing being spun varies greatly. I have one that varies from 165W, a 5.5kg, rated at 200Watts but this has the 60Series motor. I have no 100Series in a washer to check what F&P rate them as. was working fine... til the smoke got out. Cheers Gill _Cairns, FNQ |
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| Gizmo Admin Group Joined: 05/06/2004 Location: AustraliaPosts: 5078 |
That 160w might be an average over the wash cycle. I know the fuse is a 4 amp rating, so thats good for just under 1000watts. I'm sure the spin uses a lot more than 160w, I'll need to connect up my ampmeter on my washer to see. I think we have to be carefull not to over analyse the F&P. A member of another forum once said "I cant see anything good about the F&P design". But there are hundreds, if not more, of us using F&P's in our windmills with great success. If we were to look deeply at any design we would find enough reasons to not use it. The F&P isn't the most efficient alternator we can use, but its cheap, tough, reliable and easy to integrate. Its a bolt on alternator that you can pick up for less than $100. If you need more power you can increase your turbine diameter and stack 2 or more F&P's. And if you break your stator or hub, you can go down to your local white good electrician and buy spare parts! I could be wrong, but a brand new F&P stator and hub is still cheaper than a set of new magnets for a axial of the same power. If we want to look at efficiency only, the axial is a better design, but if we want to include reliability, ease of use and cost, then the F&P shines. Just my bit. I'm not a big fan of the axial, all I seam to see are stories of them burning out, or the magnets flying off, or somthing letting go because the furling was not spot on or there was too much line resistance, etc. I've never heard of a burnt out F&P, and I think this should be taken into account when comparing the designs. Glenn The best time to plant a tree was twenty years ago, the second best time is right now. JAQ |
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| KiwiJohn Guru  Joined: 01/12/2005 Location: New ZealandPosts: 691 |
I think of a few good things about the F&P design. a. It is 'open' in the sense that it is easy enough to reconfigure windings in the search for the best match between the source and the load. b.It is a rather large diameter for the power handling capacity of the machine. In many ways large diameter compensates for low RPMs. c. It is not very heavy. d. It is not difficult to rewind. e. It is not difficult to increase the magnetic field intensity by substituting better (stronger) magnets. f. The design is good for air cooling, just what is needed on a windmill! g. The mounting shaft is strong and the whole configuration is handy including in a windmill design. |
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Bryan1 Guru Joined: 22/02/2006 Location: AustraliaPosts: 1344 |
Well guys it has been blowing a gale here today and athough I do have my 350 watts of pv hooked up the current meter the genny is on I was seeing a top of 18 amps going into the batteries which were sitting on 27.2 volts. The sun wasn't shining at the time as it was raining and the mill was just starting to furl. So for a 100 series F&P un-rewired hooked up in delta with those 400 volt 470uf caps back to back it aint a bad result and no the caps wern't hot at all either. My mill has survived 100+ K winds so I never bother to short it out and since i fixed Ross's dumpload design the batteries will never overcharge. As far as cogging goes my opnion if they isnt enough wind to turn the blades abit of cogging is a non issue. Now a far as noise goes we can hear the genny wind up from the house over 50 metres away, once she's spinning the niose goes away so my missus is finally convinced all my tinkering on wind gennies isn't a failure and now she wants a genny on the house. Cheers Bryan |
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| GWatPE Senior Member Joined: 01/09/2006 Location: AustraliaPosts: 2127 |
I am still waiting for stronger winds. I have put a maximiser on the F&P now. The standard 100S in delta with twisted poles and capacitors now has cutin at approx 60rpm, at about 10W mill output. This is in 2.5m/s wind. I almost have for the F&P mill, my objective of, if the mill is turning then power should be output to the battery, and the power output should be proportional to wind energy, up to the point where the mill starts furling. I would like to see peak power now at 350-400W. This unit has already produced 300W. I will manage excess power that is unable to be directed to the grid with a diversion load. The chinese mill controller I have does limit max battery voltage to 30V, by heavily AC loading the mill. I have yet to incorporate a BMS into my RE setup. Most days the battery is cycled down to 25V or so and then recharged to a boost level of 28.6V, before returning to float at 27.6V. I hope to incorporate a PL20 type BMS and somehow interface this to my gridfeeding ccts. The variable battery voltage, depending on the state of charge of the battery is a problem. I intend to use the PL20 as a trigger sensor. When triggered the BMS will measure and set the reference battery voltage that needs to be regulated to. A picaxe controlled PWM output will control the reference voltage pin of an SG3524. This will allow the 3524 with current limiting, voltage input regulation and output regulation and numerous interlocks to adapt to the SOC voltage of the battery and this should allow my battery to be correctly maintained. This is hopefully the final step needed for full automation of my setup. I intend to replace my battery with a LiPo setup eventually, but I needed a programmable and adaptable BMS first. I did not realize how complex this setup has become. Luckily the tasks could be separated and controlled by individual processors. There are 5 picaxe 08M micro's and 2 independent SG3524 PMW's working together to make it happen. The picaxe handles complex measuement, timing and decision logic. Each micro has most I/O used and they share no common earth. The ccts require optocoupling to overcome ground loop and measuring errors. I have found that a single micro would require linear analogue I/O optocoupled components. I found it easier to separate the tasks and process the measurements with individual micros. The control algorithm with a single micro would be unmanagable. I was able to reprogram individual micros and not affect complex memory and timing of other operating modules. I can easily remove a module without affecting others. I have yet to standardise some older modules to use a 3pin programming cable. Maybe one day, all the wiring may be hidden and the indicators located on a single panel with OFF/ON/AUTO switching of major components and external relays. Photos are still a while away. The series 80 rewire is a star 2S7P arrangement. I drilled holes in the plastic to hold the winding terminations. The star points join on the back side of the stator. I sacrificed 1/2 a turn to simplify the wiring. The outputs will be joined on the front side with 1.5mm solid copper in a transmission style arrangement. I will attach fly leads and use blue point type joiners in the yaw box. I need to only join groups of 3 wires this way, without any soldering. The caps will still be in the yaw box. I use heavy duty spade terminals to connect to the slip fingers. This way all electrical can be removed if necessary with a screw driver. I have some more blades, so I may also be trialing a shorter set. I will have some tuning of the tail boom if I go this way. Gordon. become more energy aware |
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| GWatPE Senior Member Joined: 01/09/2006 Location: AustraliaPosts: 2127 |
Winds have finally come with avengance. The strong winds, up to 90kph have revealed possible problems with voltage boosting with capacitors. My mill demonstrated runaway with a 100 series in delta with 230uF caps between phases into a 24V nom battery. The current did increase and cutin was at a lower rpm, but the mechanical limits of the mill have to be selected to give a not overdriven system. The furling must prevent the rotor from overdriving the alternator. I saw the current increase and then fall to zero into the battery with an increase in rotor speed with an increase in windspeed. This happened with and without capacitors, but happened at lower rpm with capacitors. I have cut 300mm from each blade and 300mm from the tailboom length. I have twisted the poles to a point where the cogging is negligible. The rotor starts easily in very light winds. There appears to be no change in max mill output. Measured maximum current was 11.5A into 28.2V. I am using a maximiser and have adjusted the maximiser settings to only boost from 0-20% maximum power. I have incorporated a chopper stabilization of the booster, to prevent latching of the control unit. The mill cutin voltage is 12V into a 24V battery. The system maxed out my gridfeed inverter today. My 2 mills are now performing in a similar fashion. The only problem now is there is no way to electrically stop the F&P mill. Even with the mill AC output shorted, the blades have enough torque to run the mill up to full speed and furling with sustained strong winds. The chinese mill controller does hold the output to 30V Max, but cannot slow the mill. I will be monitoring the F&P unit, but so far this combination allows a small blade set and battery charging as long as the mill is turning, even in light winds. The acoustic hum of the stator is now reduced to an acceptable level as well. I will leave things alone for a while. It will be interesting to see the if second mill gives a measured kWhr increased output to the wind RE component. Gordon. become more energy aware |
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| GWatPE Senior Member Joined: 01/09/2006 Location: AustraliaPosts: 2127 |
I have had great success with the F&P mill. A series [similar to Bryan] and parallel [similar to Dennis]capacitor arrangement in the mill output seems to work well on my 24V system. I have recorded a maximum 550W. The wiring had to be upgraded to handle the extra power. I have integrated the boost maximiser with a modified program to better exploit the higher power outputs and changed windmill response. I have what I would call an ideal windmill now. the twisting of the pole fingers has reduced the cogging and now the slightest winds start the mill. The boost cct extracts power in a controlled way, up to normal cut in, approx 50W before turning off at 2A battery current. The capacitors allow the mill to closely track the windspeed and assist in the conversion of the high generated voltage to current at the battery voltage. I have finished the 80SP rewire and pole finger twisting. This will be tested at the earliest opportunity. The windmills I have will now eat into the base load energy demand of my house. My aim is for all of the solar to be exported to the grid. Having a surplus of power to export has resulted in a power bill credit for winter. Gordon. become more energy aware |
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| Gizmo Admin Group Joined: 05/06/2004 Location: AustraliaPosts: 5078 |
Very good results there Gordon. You've certainly come a long way in the last couple of weeks with that F&P. I noticed the posting by Bryan on Fieldlines, good reading. Flux is a smart man but he dont like the F&P I think his comment "Sorry I haven't been following what you are doing in Australia, the F & P is not available here so there is no interest in it." defines his views.
I think Oztules stood up for the F&P crowd well, well done Oz. 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 posted my own comments on the fieldlines forum. I saw some of my own stuff there as well. Thanks to those members who thought it worthy. I am waiting for some more bad weather to check out the top end power levels some more. I am very pleased with the performance now of the 100S. I have tried the 80SP and the jury is still out. Maybe useful with more boost at the bottom end in a 24V system. LC and RPM will be and individual trial and error process. We all have different blades, so RPM v windspeed will be different. Power and component interactions are so frequency and power dependent that I think a simple calculator for all systems would not be possible. I have wooden piggot type 2.4m blades. Others have wooden 3m blades. There are fibreglass, PVC, Carbonfibre, plastic, composite etc etc in many varying airfoils and Alternator configurations. I don't think I am able to correlate enough data to help all combinations. Now that the stator losses appear to be reduced, I will be looking at alternator hum reduction. Twisting the poles has reduced it significantly, but I will now look at carbonfibre or fibreglass binding of the poles. There must be flexing of the pole fingers as they pass by the magnets. This is adding to my project list. I hope the readers over the Tasman get the opportunity to test some of the other stator combinations. I would imagine the micro hydro members could test the power transmission aspect that caps seem to offer. The DC-DC conversion aspect should be a plus too. It may be a while before more comparison data from others can be submitted. Gordon. become more energy aware |
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philb Regular Member  Joined: 05/07/2008 Location: United StatesPosts: 96 |
Hi Gordon, I have to think that you are correct about the flexing of the fingers. I wonder if the stator on my Piggot style alternaters are flexing in and out between the two magnet rotors. That may be another solution here. Keep up the good work. I look forward to your posts.  philb |
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| GWatPE Senior Member Joined: 01/09/2006 Location: AustraliaPosts: 2127 |
Hi philb, My axial flux mill with 2mm thick stator was particularly difficult to make strong enough to stop the flexing. I hope to be able to dismantle at some time and photograph all bits. I have posted a picture on this site before of the stator. If I use carbonfibre, I will need to keep it away from the magnets, as carbon is a conductor. Gordon. become more energy aware |
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