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coil dimensions
By nudisttrucker1, Section Newbies Posted on Sun Dec 23, 2007 at 08:05:52 AM MST
coil dimensions

Can anyone tell me what the inside coil dimensions should be if I'm using 2" x 1" x 1/2" Thick, Grade N42, Ni-Cu-Ni Coated Rare Earth Neod magnets? I am trying to make a coil winder. I am needing to know how far apart to put my pins at the top and bottom

coil dimensions | 12 comments (12 topical)

Re: coil dimensions (3.00 / 0) (#1)
by disaray1 on Sun Dec 23, 2007 at 05:43:19 AM MST

Although I havent gotten to that point in construction yet, the standard on this seems to be (from what I've read)... about the same size as your magnet, maybe slightly smaller, maybe slightly bigger. So, about 1"X 2" give or take a little. Hope this helps.

David

Re: coil dimensions (3.00 / 0) (#2)
by Kevin L on Sun Dec 23, 2007 at 08:42:28 AM MST

Yes, the general idea is the same as the magnet size. Slightly larger for reduced risk of cancellation.

Has anyone wound a torrid coil stator similar to this file that flux has stored? If yes could you send information on number of windings, wire gauge, dimensions, and spacings of coils/mags etc.

[ Parent ]

Re: coil dimensions (3.00 / 0) (#6)
by joestue on Fri Dec 28, 2007 at 01:19:53 AM MST

about the toroidal alternator:
http://www.fieldlines.com/comments/2007/6/10/154449/422/8#8

[ Parent ]

Re: coil dimensions (3.00 / 0) (#3)
by kurt on Sun Dec 23, 2007 at 03:44:30 PM MST

Kevin L, talk about a thread hijack..... you know that is not polite. i should send a nun to your door to bust your knuckles but good with a ruler so you remember but sadly we are all out of nuns so consider yourself publicly reprimanded.

IRC
just a personal rant carry on.

Re: coil dimensions (3.00 / 0) (#4)
by Kevin L on Sun Dec 23, 2007 at 10:09:12 PM MST

Father Kurt,

Sadly I have never had much tolerance for the double standards of the Catholic Church.
You assume to know what I think is and isn't polite when I have seen many of the singular posts on this board roll around many topics by many of the long term members of this board when the initial question was asked and answered.
I find the admin on this site unable to follow the rules they have put in place for those posting here. (rude comments are NOT tolerated here) A simple indirect comment would have sufficed, unless your intent was biased from the beginning.

I have been on this board since 2001 in one form or another and have been using this account since 6-2003. I believe I have always been straight forward in my postings.

You can delete my account and I will look for a board a little less anal.

[ Parent ]

Re: coil dimensions (3.00 / 0) (#5)
by icicle on Thu Dec 27, 2007 at 12:12:35 PM MST

I've also been reading this board for quite some time. I'm going to stay out of this dispute, But it seems that someone wroke up on the wrong side of the bed.
As I under stand it, the coils should be the same as the magnets on the inside of the coil.

If in doubt, Read the directions!!

Re: coil dimensions (3.00 / 0) (#7)
by HomegrownPower on Fri Dec 28, 2007 at 07:11:16 PM MST

lol Very well said !!! but he may not have the directions :)~~lol

My directions called for a small block of wood the same size as the magnets . These small block the same size and thickness had small notches at each corner about half the size of the pins being used . Making the inside of the coil perhaps 1/16 larger than the origional block you wrap the coil around . You can kinda use the pins to help bend each wrap of wire straight as you wind the coil .

Hope that helps .

[ Parent ]

Re: coil dimensions (3.00 / 0) (#8)
by finnsawyer on Thu Jan 03, 2008 at 09:45:57 AM MST

Sorry to be late with this, but I was locked out from posting for about a week. Like most things with wind power it's not that simple. There is a school of thought that one actually can gain by making the coils smaller than the magnets. I'm surprised no one brought it up. For one thing smaller coils have less resistance per turn. While less flux will be passing through a smaller coil what really counts is how or at what rate the flux changes when the coil straddles the gap between adjacent opposite polarity magnets. That's when the maximum voltage in generated. If your 2 inch by 1 inch magnets have an average separation of 1/2 inch you could add to the maximum voltage by decreasing the coil width to 3/4 inches or less. You will have increased the overall resistance and changed the shape of each half cycle voltage pulse. There were some comments made about this in the past. you might try to find them.
GeoM

Re: coil dimensions (3.00 / 0) (#9)
by TheCasualTraveler on Thu Jan 03, 2008 at 09:54:44 AM MST

""You will have increased the overall resistance and changed the shape of each half cycle voltage pulse.""
Should that say Decreased overall resistance?
Andy
[ Parent ]

Re: coil dimensions (3.00 / 0) (#10)
by finnsawyer on Thu Jan 03, 2008 at 10:10:05 AM MST

The idea here was that we essentially added more windings to an existing coil in the center area. You probably don't want to get rid of the outside windings if the original coil design was working properly. That's not to say you couldn't and that would reduce the resistance turn for turn, but it will affect the voltage too. There are those who have had experience with this and it would be nice if they shared their experiences again.
GeoM
[ Parent ]

Re: coil dimensions (3.00 / 0) (#11)
by TheCasualTraveler on Thu Jan 03, 2008 at 11:29:33 AM MST

I see, so your adding coils and resistance but the increased voltage more than compensates for it. (I think)
Andy
[ Parent ]

Re: coil dimensions (3.00 / 0) (#12)
by finnsawyer on Fri Jan 04, 2008 at 08:36:58 AM MST

That would be the idea, but is not necessarily true. Adding more inside turns increases both the peak voltage and resistance. But how depends on the geometry and whether the magnets are round, rectangular, or wedge shaped. With rectangular magnets, for instance, the gaps between magnets become wedge shaped, a complication. It also depends on how the alternator output is used. If both the resistance and voltage increase by 10% you will gain power output when feeding a matching resistive load due to the voltage squared over resistance behavior. When charging a battery the current and power into the battery is proportional to the rectified voltage minus the battery voltage divided by the resistance. The gain in power would be small. On the other hand, the cut-in RPM would be reduced. In many cases people find it is necessary to add resistance externally to avoid stall. So, one could add resistance and lower the cut-in RPM at the same time by adding windings at the center. But, how would one do that after the fact, and would it really help, anyway?
GeoM
[ Parent ]

coil dimensions | 12 comments (12 topical)

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