Author Topic: phase check? (Read 2968 times)

theTinker · « **on:** January 10, 2006, 03:08:10 PM »

hey everyone,

This will be a very basic question to the experts, i think any intermidate might be able to answer it

i have 24 magnets and 24 coils(all touching side by side), if i place a magnet at the coil touching area what phase is this?

all the examples of single phase ive seen have all the norths over the "right" leg and the south over the "left" leg, but with my arrangment it would alternator frequently.

now i plan to split the 24 coils into 2 different "sets"

first set: north pole on right leg, south pole on left leg

second set: south pole on right leg, north pole on left leg

is this two phase? and is this ok?

also another small question if anyone could answer it. with this arrangement i always see 2 poles over each coil? why is this bad?

(i figure it must be otherwise everyone would be doing it )

Thanks in advance people.

Flux · « **Reply #1 on:** January 10, 2006, 08:29:10 AM »

Without a diagram I am not sure what you are doing but it seems like single phase, you won't get 2 phase with a simple arrangement of coils and equal number of magnets.

Why is it bad and no one does it "because it is single phase"

Flux

theTinker · « **Reply #2 on:** January 10, 2006, 09:47:15 AM »

cheers for the fast reply flux.

below (i hope) is a diagram of what i am doing and of what i think a single phase is/was.

thanks for the input.

windstuffnow · « **Reply #3 on:** January 10, 2006, 11:00:31 AM »

Either way its still a single phase arrangement. Using 18 coils would make it a 3 phase. Each phase having 6 coils.

.

theTinker · « **Reply #4 on:** January 10, 2006, 04:19:38 PM »

ah i better change my single phase thinking. i would of guessed this was 2 phase so thanks for the info.

is there any reason why i shouldnt connect all the coils in series?

will the 2 "sets" cancel each other out or will they stack just fine?

maybe somebody might run thier brains over the following points as i see it and comment if im wrong:

: i know single phase is not a desired option to most but as i see it, i fit 24 coils in with this arrangement instead of 9/18 options.
: instead of cogging every "phase power peak"(such as the second part of my diagram shows), with the whole circumfrence of my rotor containing the 24 coils it should be pretty smooth all around.
: all of my coils are generating peak power very frequently.

willib · « **Reply #5 on:** January 10, 2006, 04:50:35 PM »

it looks like two phase to me..

if you connect all odd num. coils together = phase 1

all even num. coils together =Phase 2

Yes if you connect all coils together it will cancel out.

2 Not as smooth as three phase , but woofferhound will say that it dose'nt run that bad !

i have never tried two phase , but the peaks will alternate.

whatever happened to three phase??

RP · « **Reply #6 on:** January 10, 2006, 06:28:01 PM »

Technically you could call this two phase but in reality since they're 180 degrees out of phase it's simply reversed polarity for the even numbered coils. If you look through this site you'll see references to reversing the connection of every other coil in single phase alternators for just this reason.

Typically 2 phase systems are 90 degrees put of phase.

willib · « **Reply #7 on:** January 10, 2006, 06:40:49 PM »

have you got an example of that? where the two phases are 90 deg, out of phase?

this is my thinking - if you were to connect all even num. coils and bring them out and connect them to a rect. and do the same for the odd num. coils , you would have ( i believe ) a two phase gen. with half the resistance of a single phase gen with the same num. of coils..

RP · « **Reply #8 on:** January 10, 2006, 06:48:19 PM »

What you're describing is the same as taking half of the coils of any single phase alt and connecting them in parallel with the first half.

electrondady1 · « **Reply #9 on:** January 10, 2006, 06:52:57 PM »

in the example designated "my configuration"if you drop another set of coils over top of the first. so that the legs completly cover the white spaces it would be two phase.

willib · « **Reply #10 on:** January 10, 2006, 08:32:23 PM »

You're right , they are the same , there is a slight difference though ,in the first example the coil legs can be half the size of the ' standard single phase ' gen.

terry5732 · « **Reply #11 on:** January 10, 2006, 09:43:18 PM »

So the "improvement " to two phase is to have a set of coils that is a coil thickness away from the mags?

Flux · « **Reply #12 on:** January 11, 2006, 02:20:35 AM »

electrondady has described the conventional 2 phase winding beautifully. For radial machines with slots all polyphase windings use coils that overlap at the end.

All are derived from single phase by adding more identical phases displaced in time so that they peak at different times. For 2 phase the displacement is 90 deg, 3 phase it is 120 deg and 5 phase would be 72 deg.

The basic full winding will have the same number of coils as magnets per phase.

This is normally wound as a lap winding with 2 coil sides in each slot. An alternative is to do it as a concentric winding with only one coil side per slot and you leave out alternate coils, doesn't matter as you put more turns in each coil to keep volts the same.

These winding arrangements become extremely difficult with an axial design with no core slots and it turns out far better in the end to keep the windings on a single layer. You can achieve this by leaving out even more coils and when you have a pole to coil ratio of 4:3 a 3 phase will fit into a single layer. 6 pole 5 coil works for 5 phase with even coils missing.

I can't see why anyone would want to do it but 6 pole 4 coil will give you 2 phase.

If your coils at 12 & 6 o'clock are over magnets, the ones at 3 & 9 o'clock will be half way between magnets.

Flux

monte350c · « **Reply #13 on:** January 11, 2006, 06:20:51 AM »

Here's some good reading on this subject. Just scroll down the page and check out Chapter 3, Alternating Current Generators.

http://www.tpub.com/content/neets/14177/index.htm

There's more good basic info on alternating current:

http://www.tpub.com/neets/book2/index.htm

The site is a wealth of knowledge!

Ted.

ghurd · « **Reply #14 on:** January 11, 2006, 08:39:29 AM »

A little late, but part #1 looks a lot like The Wood 103. Single phase.

I could see how part #1 may have a little lower resistance.

http://www.otherpower.com/woodmill.html

G-

theTinker · « **Reply #15 on:** January 11, 2006, 09:44:52 AM »

thanks for all the comments so far. been very helpful.

what i gather from all this then is that "my configuration" is single phase. To make sure that the even coils dont cancel out the odd coils i should either

A: keep the "sets" seperate until after rectification OR

B: switch the start and end wires from each odd coil(or flip the coil?)

are these two options valid?

(note: 3 phase i dont find relevant to me as the size of my rotors are pretty large in comparison to my magnets, which is why im not doing it, having LOTS of small coils is a easier to build choice at the moment.)

if i understand correctly then below is what the power output from the "my configuration" and 2 phase is.

if this is correct, could somebody elighten me to how rectification on "my configuration" is done, is the "negative wave peak" just added to the positive one given me a really high voltage peak? (if this makes sense, im still new to this so i might have some wrong assumptions.) heres a diagram of what i mean.

thanks again.

RP · « **Reply #16 on:** January 11, 2006, 10:10:06 AM »

"is the "negative wave peak" just added to the positive one given me a really high voltage peak?"

Yes, You've got it. This is assuming that you reverse the polarity (or physical orientation) of every other coil AND connect the two coil groups in series. An alternative is to connect the two polarity corrected groups in parrallel and get the same voltage but twice the amperage.

Sometimes you'll see references to series-parallel, etc. on this board. What folks are doing is coming up with the best combination to get the voltage they need with the maximum current at that voltage.

theTinker · « **Reply #17 on:** January 11, 2006, 10:33:02 AM »

woot im so happy i figured that one

cheers RP for answering all them last ones(quite tidyly too).

thanks to all that answers and contributed too.

got alot from it

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