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Forum Index : Windmills : my Lenz2 attempt
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gj4533 Newbie  Joined: 28/12/2008 Location: United StatesPosts: 19 |
Help please, I'm concerned about my stator coil connections. I'll try to be exact. 12 magnets,9 coils, 3 phase. The connections for each phase is as follows. outside of coil A1 is start. inside of coil A1 connected to outside of coil A2, inside of coil A2 connected to outside of coil A3. All coils are layed the same (none flipped over). Outside of coil B1 is start. Outside of coil C1 is start. Inside of coils A3,B3 and C3 connected together. Please please please tell me this is right. I've been reading and found some opposing info on this. I've put this mill together and I feel some resistance (cogging?) even when nothing is connected to the wires. There isn't any wind today so I don't know if it even works, other than producing a few volts from a hand spin. The distance from the mags to the stator is extremely small, maybe .03" at most. Please let me know if I have to make a new stator or not. Thank you Gary Johnston Buffalo, NY G.Johnston |
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vawtman Senior Member  Joined: 14/09/2006 Location: United StatesPosts: 146 |
Are the mag poles set properly?You can test by holding another dinkie mag in your hand around the rotor. |
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| gj4533 Newbie Joined: 28/12/2008 Location: United StatesPosts: 19 |
Yes, That took me the most amount of time, double check triple check and then do it again before epoxying them in. should there be some resistance with nothing connected? When I turn a fan on it, it turns but, it slows at certain points like it's changing to the next phase. I just don't know if this is normal or not. Are the coils right? Gary Johnston G.Johnston |
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| vawtman Senior Member Joined: 14/09/2006 Location: United StatesPosts: 146 |
Here's a link for ya from Dan at otherpower [:) |
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oztules Guru  Joined: 26/07/2007 Location: AustraliaPosts: 1686 |
Sound to me like it is connected right. The link Vawtman has pointed to should allay your fears. There should be no resistance to turning other than bearing resistance, when open circuit. No cogging at all. If there is a non-free rotation, check for stator/rotor interference (touching anywhere) or if the bearings are too tight on the shaft or some other mechanical problem. If they are hooked up as you describe, there is no place to get the cogging, or resistance to turning from the electrical system itself. If your using pillow blocks, are they aligned properly etc etc. ..........oztules Village idiot...or... just another hack out of his depth |
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| gj4533 Newbie Joined: 28/12/2008 Location: United StatesPosts: 19 |
No rubbing no interference no touching. I took it apart (thank you jacking system), put it back together with only one mag plate on and it seemed fine, so I thought maybe it was the washers on the top and bottom of the stator being attracted to the outside diameter of the magnets and put it all back together again without the stator, it spun freely. Took it all apart and put it back together again and got the same results as before. Then I tested each of the phases seperately and found that I got the same voltage out of 2 of them and 1/4th the voltage out of the last one. Bummer. Because there is 2 windings for each coil I seperated the the bad phase's coil and tried it again and got better voltage but still less than 1/2 what the others are. Time to build my 2nd stator. Darn, I was so proud of the first one. Gary Johnston G.Johnston |
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GWatPE Senior Member Joined: 01/09/2006 Location: AustraliaPosts: 2127 |
When I set my first stator up, I hooked each phase up to a power supply. I used about 2A current, and with a magnet, I checked each coil for strength and polarity. This can be done before any casting of resin. Coils can look the same, so at least you can confirm the wiring is right, up to the casting stage. Gordon. become more energy aware |
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| gj4533 Newbie Joined: 28/12/2008 Location: United StatesPosts: 19 |
Thanks Gordon, I checked the new coils today, They are fine. But I haven't poured it yet, tomorrow. maybe before the weekend is done I'll have a windmill that works. $5 says there's no wind.  Thanks for all the input people.
Gary Johnston Buffalo, NY G.Johnston |
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| gj4533 Newbie Joined: 28/12/2008 Location: United StatesPosts: 19 |
finished my new stator last thursday and over the weekend I put it together and this one works. At 60 rpm it gives 7.2 volts unloaded. we didn't have any wind most of the weekend but I did drag it outside when there was a slight breeze and it was almost 10 volts and during a little "gust" it was over 14. Today was actually scary. We have had pretty strong winds most of the day 20-30 mph with gusts into the 40s. at one point it was over 40 volts and turning quite rapidly. Which brings me to my next adventure, I now have to make a centifugal speed limiter for the mill. My brain is already spinning (no pun intended). The abrupt change in resistance of the stator from shorting it out puts a tremendous amount of tension on the (4) 1/4" allthread studs that hold the stator in place. I think a mechanical limiter is the way to go for me. Anyone have any experiences with doing this? Hats off to Ed Lenz for a fine pice of engineering on this mill. It's very exciting for me. Thanks to everyone and anyone that has helped me along the way. Gary Johnston Buffalo, NY (TO's new home) G.Johnston |
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| GWatPE Senior Member Joined: 01/09/2006 Location: AustraliaPosts: 2127 |
combined with this means that you have 195 turns giving 7.2V @ 60rpm, or 36mV/turn at 60rpm. My new alternator has 45mV/turn at 60rpm. What airgap do you have between the magnets, where the stator coils are? The mV/coil seeems a little low considering the amount of magnet there seems to be. These are Neo magnets I presume. Have you measured the resistance of a single phase yet? on a point above. My old mill, AxFx, at 750W output can be stopped very quickly by shorting the outputs. The stator is held to the stub axle with 6x 1/8" screws that are at a distance 2" out from the axis of rotation. All of the power/torque is transferred from the stator to the axle by these screws under electric braking. I believe that in your alternator, that the bolts are a lot further from the axis of rotation. What power are you expecting this alternator to usually produce. I envy the tools you have access to. The milled magnet placement surfaces brought back memories of making my first AxFx alternator all those years ago. Is there any scope for optimizing the magnet gap and wire turns etc? Gordon. become more energy aware |
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| GWatPE Senior Member Joined: 01/09/2006 Location: AustraliaPosts: 2127 |
Hi Gary, I have just re-read your last posting and you have not mentioned if the voltage was before or after the rectifiers. Either way, you have presumably wired in star. This means that the volts/turn is 1.7x lower again compared to a single phase output. Are these magnets quite thin? Hope to hear how your testing is going. Gordon. become more energy aware |
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| gj4533 Newbie Joined: 28/12/2008 Location: United StatesPosts: 19 |
Gordon, The magnets are .250" thick (thin). I bought them at magnets4less.com. supposedly n42. The air gap was figured after pouring the first stator. It was .550" near the inside diameter and .515" near the outside. So when I machined the magnet plates with the hub and alignment tang I made the distance between them 1.06". The magnets are .25" so I machined the pockets for the magnets .03" into each face. This would (in theory) produce .03" on each side of the stator clearance. Well the first stator was no good, the second one turned out much flatter and around .515" so that increased the air gap on each side to around .055 or so. In reality it seems tighter than that. I own a very cheap volt ohm meter. Today I tried to measure the resistance for you. Shorted out the meter reads .6 (200 ohm setting) and all 3 phases read 1.5. The voltage was measured after the radio shack full wave rectifiers. I was estimating rpm by using a stopwatch and trying to see how long each revolution was. I did it 6 times and got the same time 1.04 each time. All in all I'm excited about what it's doing. I'm not trying to run my house with this, what I would like is to charge a battery to power my electric fence for the horses and also power enough leds to light the barn up so I don't have to pay the expense of running electricity to the barn just for lights, I don't see any other reason to have electricity in a barn. I was also considering running 12 volts through the house for power out lighting or permanant lighting for rooms that don't need light all that much, like the pantry. But who knows for sure Gordon. I plan on building another one of these just like the first one. I plan on putting this up on the side of a pole and putting the other one on the other side. I may end up with more power than I need, then I'll use it for something. As far as having the machines available to me, you're right, It's very nice. Through the years I've invented and manufactured a few things I couldn't have made without the opportunity I have to use the machines. The only drawback is that it's kind of like being a doctor. When someone finds out you're a machinist, usually the next thing out of their mouth is "I've got this broken thingy, could you make me one?" .. just like the doctor " I've got this pain in my arm doc". I'm also lucky to have been introduced to an electronic engineer that lives really close to me and he's made a couple of windmills and maybe he could help me and I could help him (barter). He already told me he'd come over and test it for me. My life is pretty busy right now with working 50 hours/week and wife,2 kids, 2 horses and a dog, all living in a very small duplex and I just found out the bank will let me build the house we dreamed of now going on 2 years. I play with the wind when I can. I appreciate you being there Gordon, you keep the fire lit under my butt. Thanks. Gary Johnston Buffalo, NY G.Johnston |
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| GWatPE Senior Member Joined: 01/09/2006 Location: AustraliaPosts: 2127 |
Hi Gary, the simplest way of measuring low resistance, is to apply some current. I use a 2A current limited supply. Once the current is set, just measure the voltage across the unit with your multimeter. 2A will give 2V for 1ohm. I test individual coils this way. You can also check the coil polarity as well with a small bar magnet. Gordon. become more energy aware |
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| gj4533 Newbie Joined: 28/12/2008 Location: United StatesPosts: 19 |
I ran across this controller for windmills, I'm not sure if there is a dummy load inside or not. Anyone know of this product? Controller Gary Johnston G.Johnston |
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| gj4533 Newbie Joined: 28/12/2008 Location: United StatesPosts: 19 |
It's been a long time guys, I've been busy building a house and such. I played with the mill a bit and running at 60rpm I wasn't satisfied with the no-load voltage. With the 2X60 turn coils it was not quite 9 volts. I used the same wire and made a new stator with 100 turns per coil. At the same rpm it now puts out 14.2 volts. I do understand that I'm losing amps, but at least I'll get something usable at very low wind speed. That brings me back to another post I made a while back. I built a charge controller for the battery. I think it's called a comparator. Etched the copper clad board, assembled it, didn't think it was going to work and was pleasantly suprised to find it did. So, why not wire a stator with 2X60 turns each coil and have all the input and output wires of all the coils come out of the stator and using a comparator circuit, switch each coil from 2X60 parallel to 1X120 series. That way when the winds are slow the circuit will switch to "series" each coil and you would get enough voltage to at least trickle charge, and as the wind picks up and you reach a certain voltage your voltage comparator switches to "parallel" each coil and now you'll get enough voltage with more amps. How many relays will I need? Gary Johnston Buffalo, NY G.Johnston |
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Gizmo Admin Group  Joined: 05/06/2004 Location: AustraliaPosts: 5119 |
Hi Gary It depends on how much current the relays need to handle and what relays you can find. You need a couple of changeover contacts per phase. If you can source automotive spotlight relays cheap, then you would need 6. I need to draw up a circuit, but a little short of time. Glenn The best time to plant a tree was twenty years ago, the second best time is right now. JAQ |
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| Gizmo Admin Group Joined: 05/06/2004 Location: AustraliaPosts: 5119 |
OK, quick and ugly circuit. This is for one phase, 2 coils. The relay has 2 changeover contacts. 
Glenn The best time to plant a tree was twenty years ago, the second best time is right now. JAQ |
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