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Forum Index : Electronics : MAGNETS
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Racingken Newbie  Joined: 24/11/2011 Location: United StatesPosts: 28 |
Does anyone have any information for whether the gauss of a magnet I choose when choosing magnets should be higher or lower? whether I should shoot for lower or higher pull force and a higher gauss, and or lower or higher gauss/permeance coefficient? I want to make my own generator for a low wind speed Hawt. I will be making as much of it as I can. I need to try and build one that will start in a 3-5 mph wind, as I get a lot of days in the 2-7 mph range. Sorry about that I don't think I had this worded quite how I meant, so I changed it a little. Racingken |
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mac46 Guru  Joined: 07/02/2008 Location: United StatesPosts: 412 |
Hello Racingken, 3 to 5 mph wind is a very light wind to be trying to harness for elect. power. Read VK4AYQ.s posts, as he has some very clever ideas on this wind speed range. Good wind and sunny skys, Regards, Mac46 I'm just a farmer |
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| Racingken Newbie Joined: 24/11/2011 Location: United StatesPosts: 28 |
Thank you for the info Mac I will do a search for his post so I may learn more. I hope things are going well on your end. Ken Racingken |
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Tinker Guru Joined: 07/11/2007 Location: AustraliaPosts: 1904 |
Your output voltage depends: on the strength of the magnetic field, on the speed at which the coil cuts through it and on the multiplying effect of the number of turns in the coil. In each case more is better. But you will find that there is very little energy in low wind speeds. Klaus |
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| Racingken Newbie Joined: 24/11/2011 Location: United StatesPosts: 28 |
Hello Tinker I appreciate your comments, I do get on average around 9 mph winds a day. I was just hoping I could build a generator that would start out put for 12 volts around 3-5 mph. But if it's not possible I can just build for as low an mph as possible. I also get winds in the 20 to 30 mph range, just not as often, and occasionally it will hit 70 mph, but that is only with a really bad storm here in the valley in California. My main concerne was I do not know what to shoot for in a magnet. I think later today I will take an old CD rom apart and use the motor in it and see what I get out of it, then take off some of the windings and see what it does then. I used to remove some of the windings in my slot cars to make them go faster when I was a teen in the 60's. So I thought I would try that out with a small motor and see what differences it has on power and voltage. Thanks again for your input. Ken Edit: Well that didn't go as planned, the wife had other ideas. Racingken |
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MrDelanco Senior Member  Joined: 12/11/2011 Location: United StatesPosts: 101 |
Check this out for an idea Alt-Generator 12 volts, 24 volts, Two magnet layers "over-under". Designed to operate from 2-10 mph. Will produce +70 volt's open with no load at 10 mph. Magnet's are N52's Regards Robert. MrDelanco:Project Videos It is not only too know what it does but to understand how it does what it does. |
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| Tinker Guru Joined: 07/11/2007 Location: AustraliaPosts: 1904 |
Don't get me wrong here, you *can* get 12V at 3-5mph winds, but only very little power (Amps) for battery charging unless your generator has rather large blades/ wings /whatever. Wind power goes up by the square of the wind speed, twice the wind speed is 4 times the power. Another problem is your blades may not spin fast enough in low winds to generate a sufficiently high output voltage. For experimenting, try a stepper motor, you find several of these in printers. If you short all the wires together it should be very hard to turn by hand. You then have to buzz out the coils and find out which connection works best. Rectify the output if you want to charge a battery. BTW, a 12V battery requires around 13.6V for charging. Klaus |
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| mac46 Guru Joined: 07/02/2008 Location: United StatesPosts: 412 |
Hello Racingken, everyone, Some people have had success in getting larger stepper motors from the web, but you really need to know what size and rpm will work for what you are going to apply it to. Many times the info is not correct as advertized. I have ordered magnets from www.magnet source.com here in the usa, with very good results. (I am not connected with them in any way). But the phone number is on their web site...I've talked to Travis Ranney at ext.149...he was very helpful. 1-888-293-9399...ext.149. Mac46 I'm just a farmer |
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| Racingken Newbie Joined: 24/11/2011 Location: United StatesPosts: 28 |
MrDelanco, Thank you for the link to your build video above. It was a very interesting build, and quite ingenious with the use of all the different used parts. Tinker, I just reread your first reply again and realized that you gave me all the information I was initially searching for. (ie something to shoot for.) Your first reply. "Your output voltage depends: on the strength of the magnetic field, on the speed at which the coil cuts through it and on the multiplying effect of the number of turns in the coil. In each case more is better." I also realize from all the research I have been doing, that more windings means more resistance, as long as it is the same diameter, well actually I did learn that between 52 and 51 years ago from my dad. I was maybe 8 to 9 when he would let me desolder resistors and solder in the new ones on the old tube type tv's. He would tell me to put the new one in by matching the colored stripes to the old one. He was a TV repairman. When I was 11 he brought home a big wooden box (about 4'x6' a box with many smaller boxes inside it. It looked like something you might see mounted on a wall to sort out different folks mail or something. As it turned out it was the Local Moose Lodges Bingo Light board. He asked me if I wanted to wire it up with all the lights and wires for the diferent letters and numbers. And I jumped at the chance. I am sorry, I get so long winded sometimes. mac46, I really appreciate the info on the stepper motors, I may buy a small one to play with till I can afford to get the Neo magnets I want to use. Not really sure what size to go with yet, as I don't know how big the magnets need to be for the output I want of around (EDIT)600 to 900 watts in maybe 15 mph winds. I also appreciate the info for who you got your mags from. I have bookmarked a website that sells mags and they have a flux calculator that shows the gauss effect at what size and gap you might use. I have been looking at magnets are in the top 20% of their gauss range. I do not know if that will matter, as the ones I have been looking at are N42's 3/4"x7/8" round the larger # is the thickness. Any thoughts anyone? can I go with less expensive Magnets and still get the watts I would like or not even get them with these? I almost forgot..... should I worry more about pull force than gauss? Racingken |
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| MrDelanco Senior Member Joined: 12/11/2011 Location: United StatesPosts: 101 |
Ken you should understand the principles of how a magnet works too get a better understanding of what type to use for what you want to accomplish. This site will help you How Magnets Work Regards Robert. MrDelanco:Project Videos It is not only too know what it does but to understand how it does what it does. |
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| Racingken Newbie Joined: 24/11/2011 Location: United StatesPosts: 28 |
MrDelanco, I read it, and I learned all that years ago while in school. I know it doesn't hurt to go over something we already learned, as we tend to forget some things if we don't use the info we learned. I think I will go buy some small guage wire and some cheaper small magnets and try making a small gen/alt for practice. If it works I will make a small wind generator for practice/ testing. Thanks for the input, Ken Racingken |
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| MrDelanco Senior Member Joined: 12/11/2011 Location: United StatesPosts: 101 |
Hello Ken; That sounds like a great idea, keep us posted while you build your project. Regards Robert. MrDelanco:Project Videos It is not only too know what it does but to understand how it does what it does. |
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| Racingken Newbie Joined: 24/11/2011 Location: United StatesPosts: 28 |
Ok I ordered the magnets this morning, Neo's N52 3/16" X 1/4". Now I just need to get some Wire, a steel disc, and some epoxy resin. I may have a disc laying around in my work bench, or somewhere near it. I will have to buy the resin. The wire I can get from an old non working motor, or maybe I still have one of the old coils from the yoke of an old picture tube in storage somewhere. So in a couple hours I will go look for that yke coil, there is a ton of wire on one of those. Although it is a small guage, possibly 20 to 26 from what I remember about them. Thanks again, Ken Racingken |
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| Racingken Newbie Joined: 24/11/2011 Location: United StatesPosts: 28 |
My order didn't go through! that could be a good thing though, I should have asked this question first. Can I use disk magnets and make round coils, or is this problematic? Ken Racingken |
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| Racingken Newbie Joined: 24/11/2011 Location: United StatesPosts: 28 |
Ok heres what I am thinking of ordering 12- N50 discs 1/2"X 1/2" With a Gauss of 4333. Here is all the information on them in the Pics, provided I get them uploaded. Do you think they will produce a usable amount of power? 
Ken An aspiring Gen/alt builder Racingken |
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| MrDelanco Senior Member Joined: 12/11/2011 Location: United StatesPosts: 101 |
Hello Ken; Your research of the magnets is good. Now have you wound any coils ? It might be a good idea to match the magnet with the coil size you are planning to use. Regards Robert. MrDelanco:Project Videos It is not only too know what it does but to understand how it does what it does. |
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| Racingken Newbie Joined: 24/11/2011 Location: United StatesPosts: 28 |
MrDelanco Thankyou for your reply. Yes, I wound a coil for a 3/4"X3/16 ceramic magnet. I bought 32 of them just to pracice with and to make a lower power gen/alt. I plan to double them up and somehow mount them to a steel disk. But ulimately I want stronger magnets to work with. I had 2 of them on a plastic disk only one thick and about 1/4" apart and about 1/16" above the coil, and when I turned them past the coil by hand, I got .8v. My coil, I wound with a 7/8" opening in the center and it was only 75 turns around. I was planning on doing 100 turns but the coil wire I was taking off of an old motor coil broke, so I went with it. Oh the wire is just over 1/32" diameter. I have another motor, a larger one that has a larger wire in it. I just have to figure out how to get the wire out of it, as it has a thick coating on the wire. Ken Stll trying. Racingken |
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| Racingken Newbie Joined: 24/11/2011 Location: United StatesPosts: 28 |
Kewl! I just bought my Neo's. I bought 32 N42s for less than $94.00 delivered. So now the coils I make for the practice mags will work for the stronger Neo's. If ya don't hear anything from me in the next two weeks........ you'll know the wife didn't appreciate my project to save energy and money! He he. 
Ken Oops, I forgot to mention the size of mags I bought. (3/4x1/2") Ken Racingken |
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