Flux and multiple PMG's

[NEO]

Hi ALL,

      First I would like to say; this is an awesome site with so much going on with ideas and innovation. I started coming here when I first discoed DanB's 17 footer and been hooked ever since...truly inspirational!

(my 1st post so sorry if i get something wrong)

Ok now to my question/s, I have read about people's theories and questions about poly rotor/stator generators. Part of my question is in respect to the back plate the steel/iron surface the magnets are mounted upon.

1. Am I correct in thinking that the rotor disc prevents the flux escaping to the outside of the stator rotor sandwich?
   
2. That being the case what would the effect be upon the flux field if magnets were mounted upon both sides of 1 rotor? and to add a twist if they were mounted back to back on the plate would pole oreintation make a difference?
   
3. I was thinking about mounting two PMGs on the same shaft in the traditional sense i.e. four rotors and 2 stators...and progression led me to having 1 rotor with two sets of magnets on one rotor plate and two rotors with one set on.------ or is it a prerequisite to have an air gap of a given size between two PMG's. Would plate thickness play a part?
   
   

I read in a post that I can longer find, comments made by Hugh, about ( I think the phrase was )"linear loss's" in poly rotor/stator designs but cant seem to recall exactly what they were.. This might answer my question if I could only find it LOL there is just soooo much info and wisdom here.

Kind Regards

ALL

[Flux]

You can use 2 stators with 3 magnet rotor discs.

If the centre disc is of reasonable thickness you can mount the magnets either way.

If the centre disc is thin they you will do better to mount the magnets so that they attract, N on one face S on the other. If you do it this way you don't really need a centre disc except to support the magnets. ( don't be tempted to use non magnetic discs with magnets on the surface ).  It is far simpler to use a steel centre disc rather than have to machine holes in a non magnetic one.

For a given quantity of magnets it is far more effective to use a single stator of larger diameter rather than stack smaller machines.

Flux

[tecker]

That comes up from time to time I think it boils down to the a wieght issue,Back to back oppisite orientation across the board is the rule. Remember the attraction of the field is very strong and the adjustments must stay in to your mechanical setup .      

[electrondady1]

i have very little information and zero wisdom but i do love to think about this stuff.

1. , yes, the iron rotors will contain and enhance the flux,
   
2. , if the rotor is too thin it might be a problem geting them to stick
   
3. , you are forming two seperate generators . better to put all the mags on two disks with twice the diam. you get something like 4 or 8 times the power
   

[NEO]

Hi thank you all for your comments.

Decision made then, larger diameter rotors using all the magnests as opposed to stacking the generators. Just as a point I was initialy thinking of the centre plate being maybe twice the thickness of one of the end plates/rotors.

however;" , you are forming two seperate generators . better to put all the mags on two disks with twice the diam. you get something like 4 or 8 times the power "

If that is a good rule of thumb then that will be the way to plan from here on in.

Thank you again.

Just for my understanding could you define the above statement? Is it because of the rotational velocity of the magnets due to the increase of rotor diameter that more power is achieved? or is there some other element to look for or include.

Regards

[tecker]

The diameter allows for more magnets , coils Ie more total copper and more of either voltage or amperage take your pick. The large rotor acomodates a medium or large blade

set also .

[Flux]

If you have a machine with certain voltage and resistance R, and you parallel it with another one you will have the same volts but resistance R/2.

Now volts are proportional to flux per pole, frequency and turns.

Now if you use the same size coils and double the number of turns, you have doubled the output volts from having twice as many coils and doubled it with increase in frequency.To get back to the same volts you need 1/4 the number of turns and you have room for 4 x csa wire. That is 1/16 of the resistance Of what you would have if you didn't change the turns. If you just doubled the existing coils you would have 2R.

Your new machine has a resistance of 1/16 x 2R or R/8 compared with the other case of R/2.

You get 4 times the power.

Flux

[Flux]

I didn't put that very well, try again.

If you have the same size coils you double the number of turns by having twice as many coils, you also have doubled the frequency, giving 4 x volts.

The rest follows as before.

Flux

[NEO]

Thanks Flux, very much appreciated.

 Makes perfect sense

[JW]

having a beer

[JW]

https://www.fieldlines.com/index.php?topic=140715.0

[JW]

https://www.fieldlines.com/index.php/topic,146584.0.html