Author Topic: magnet/coils and some rotor idea  (Read 109 times)

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rich4rdiez

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magnet/coils and some rotor idea
« on: Today at 07:32:18 AM »
Hi everyone,

I'm starting my squirrel cage v.a.w.t. project and I would like to have your expert opinion on the following subjects:

First, I have to say that my budget is tight enough to don't want to buy such expensive big size magnets, I've been looking the best price/size magnets and the ones that I already have are the best choice (maybe not for efficiency though).

I have 9x2mm neo n50 magnets, and I was wondering if technically is the same to use a lot of these instead of fewer big ones, where a few ideas came to mind.

1) To use them individually with lots of coils for the size (20mm diameter and 8-9mm air gap and 2-4mm height).



2) If option one is the way to go, would it be better/possible to put more than one row of coils in
    the stator? to take advantage of the inner space available, since the coils would be so small.



3) Maybe stack them one above the other (to gain height) and side by side like a 3 by 3 arrangement / 2 by 3 arrangement (for area coverage) and use bigger coils.



...I've calculated the total area of different magnet sizes and these small ones and by all means keep being cheaper than bigger ones even if I use a dual rotor with 3 by 3 2 stack arrangement (in a 9 pole 12 magnets that would be 432 9x2mm magnets). I also have been playing a bit with "K&J magnetic's calculator" to see magnetic differences between sizes.

So, your opinion in this matter is much appreciated since I wouldn't like to spend unnecessary money.

And one last thing, I intend to install my v.a.w.t in a rainy wet area, so trying to minimize maintenance, what do you think about this idea of bearing-less generator?
I'm also thinking that it could be upside down but don't know what that implicates yet...




Well, hoping to get some replies, I thank you all in advance for this forum, your time and good will.


« Last Edit: Today at 07:38:16 AM by rich4rdiez »

joestue

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Re: magnet/coils and some rotor idea
« Reply #1 on: Today at 04:07:50 PM »
its rather difficult for me to imagine how spending money and time on magnets for a small vertical wind turbine will get you anywhere.

even in dirt poor countries, if you can buy some solar cells, store the power in used cellphone batteries for lighting at night with leds, you'll be further ahead.

horizontal wind turbines might be practical to make from used hard drives. bolt the blades to the platters, but make the spacer that separates the two platters about 2mm thick instead of 4mm. then use a 5 inch diameter O ring as a belt to drive the second hard drive spindle at about a 10:1 belt drive ratio. adjust the blade diameter to get enough rpms to charge a single cell lithium ion battery. the diodes in the motor driver will rectifiy the ac output of the spindle motor, but you will have to poke around on the board to get the power directly from the motor controller.

problem with this proposal is, the 1$ that a used hard drive is worth (in scrap aluminum) can buy you 3 watts of solar cells. the solar might net you more power.


Better still is to find 6-8  identical hard drives and pull the servo magnets out of them and make a 4 inch diameter axial flux generator. you don't even need to wind coils. simply take the servo coils out, and glue 6 to 8 of them together for the coils.

you will need backing plates for the magnets, but 2mm thick sheet metal will work if its flat enough.
« Last Edit: Today at 04:27:34 PM by joestue »

george65

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Re: magnet/coils and some rotor idea
« Reply #2 on: Today at 07:41:05 PM »

I got myself a bunch of Server HDD's which have much bigger and stronger magnets than the regular HDD's.
Getting the things out is a complete pain in the arse and frankly not worth my time.  It's at least 5 Min per hdd and a lot of frustration to take the things out.
I must have about 30-40 Drives and I'll just throw them in the furnace to get the ally and send the leftover to the scrap yard.

I can buy one cheap used panel and get more power out of that in a day than I could from any turbine I can make for near the same money.
The magnets are just one part of an expensive, time consuming construction. For a low power Turbine you would be better just going with a pre built DC motor.

IF you have wind and no sun or want to do it for a project, terrific. On a strictly returns for cost and effort basis when solar is an option, I'm with you. Not worth the time, effort or investment for practical use.
Where I am any solar driven generator would out do any wind genny, commercial or otherwise because sun outstrips wind by about 100:1 anyway.

rich4rdiez

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Re: magnet/coils and some rotor idea
« Reply #3 on: Today at 10:36:05 PM »
its rather difficult for me to imagine how spending money and time on magnets for a small vertical wind turbine will get you anywhere.

even in dirt poor countries, if you can buy some solar cells, store the power in used cellphone batteries for lighting at night with leds, you'll be further ahead.

horizontal wind turbines might be practical to make from used hard drives. bolt the blades to the platters, but make the spacer that separates the two platters about 2mm thick instead of 4mm. then use a 5 inch diameter O ring as a belt to drive the second hard drive spindle at about a 10:1 belt drive ratio. adjust the blade diameter to get enough rpms to charge a single cell lithium ion battery. the diodes in the motor driver will rectifiy the ac output of the spindle motor, but you will have to poke around on the board to get the power directly from the motor controller.

problem with this proposal is, the 1$ that a used hard drive is worth (in scrap aluminum) can buy you 3 watts of solar cells. the solar might net you more power.


Better still is to find 6-8  identical hard drives and pull the servo magnets out of them and make a 4 inch diameter axial flux generator. you don't even need to wind coils. simply take the servo coils out, and glue 6 to 8 of them together for the coils.

you will need backing plates for the magnets, but 2mm thick sheet metal will work if its flat enough.

Thats not the point here, I actually asked something very specific, so I expect opinions regarding the topic I opened.

If I want to add solar panels in the system I would address the matter in the corresponding subject.

rich4rdiez

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Re: magnet/coils and some rotor idea
« Reply #4 on: Today at 10:37:40 PM »

I got myself a bunch of Server HDD's which have much bigger and stronger magnets than the regular HDD's.
Getting the things out is a complete pain in the arse and frankly not worth my time.  It's at least 5 Min per hdd and a lot of frustration to take the things out.
I must have about 30-40 Drives and I'll just throw them in the furnace to get the ally and send the leftover to the scrap yard.

I can buy one cheap used panel and get more power out of that in a day than I could from any turbine I can make for near the same money.
The magnets are just one part of an expensive, time consuming construction. For a low power Turbine you would be better just going with a pre built DC motor.

IF you have wind and no sun or want to do it for a project, terrific. On a strictly returns for cost and effort basis when solar is an option, I'm with you. Not worth the time, effort or investment for practical use.
Where I am any solar driven generator would out do any wind genny, commercial or otherwise because sun outstrips wind by about 100:1 anyway.

again...
Thats not the point here, I actually asked something very specific, so I expect opinions regarding the topic I opened.

If I want to add solar panels in the system I would address the matter in the corresponding subject.

MattM

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Re: magnet/coils and some rotor idea
« Reply #5 on: Today at 11:04:51 PM »
How about you take a hoop, imbed magnets in the hoop, attach short blades off the hoop as the props, and use the hoop to drive flux through a series of coils along an arc shaped support for the rollers that support the hoop from underneath its middle.  More or less use the principles of a hubless wheel.  High tip speeds and a simple design.