DIR Return Create A Forum - Home
---------------------------------------------------------
Lynx Wind Forum
HTML https://lynxwindforumhtml.createaforum.com
---------------------------------------------------------
*****************************************************
DIR Return to: Wind Power
*****************************************************
#Post#: 5223--------------------------------------------------
Newbies Questions - PMA Generators
By: maximoney1 Date: January 26, 2015, 5:46 pm
---------------------------------------------------------
I am working on a PMA design and wondering if i might get away
with the configuration in example 2 as opposed to the normal set
up as in example 1(see picture attached below). My thinking is
that the flux pathway would be channelled through the magnets on
rotor 2,en route through stator 2 towards rotor3, as opposed to
being directed through the mild steel backing plate, as two
seperate flow paths?
What are folks thoughts on this?
Futhermore, in example 2, can rotor2 still be made out of mild
steel or would it be better made out of some non metal material
eg polycarbonate?
HTML http://i1012.photobucket.com/albums/af249/maximoney1/img101_zps2rbu2ymf.jpg
#Post#: 5224--------------------------------------------------
Re: Newbies Questions - PMA Generators
By: nessprojects Date: January 26, 2015, 6:41 pm
---------------------------------------------------------
I personally would favour example 1 as magnets get intensified
when mounted to a steel backer.
Unless you really cannot go bigger with diameter for some reason
then making the diameter of the stator and magnet rotor larger
would net you a greater benefit and much more efficient.
#Post#: 5227--------------------------------------------------
Re: Newbies Questions - PMA Generators
By: maximoney1 Date: January 26, 2015, 7:06 pm
---------------------------------------------------------
@nessprojects
My magnets are only 10mm wide and 5mm thick. This would
generally dictate 'brooks' coil 'legs' of only 5mm width & 5mm
depth. This in turn limits me to a stator thickness of only 5mm.
As i go out in diameter, this thickness of structure is likely
to lack robustness. By combining two stators together, up to the
point where the coils start, then the dual stator thickness can
be 24mm, with only the coil 'legs' being 5mm. (I hope i'm
explaining it clear enough - makes sence i my mind ...lol.)
If i went with just a 2 rotor/1 stator configuration(at wider
diameter with double the coils) could i wind the coils to be
10mm thick, since there would be the two 5mm thick magnets
backed with steel acting on each side of the coil?
Thanks for your input.
Regards
Jim.
#Post#: 5228--------------------------------------------------
Re: Newbies Questions - PMA Generators
By: nessprojects Date: January 26, 2015, 7:32 pm
---------------------------------------------------------
@maxi
Wow...your comments took some digesting but I think I got it.
I am going to assume you are building a turbine of a few hundred
Ma being as you are using 5mm magnets.
The only force on your stator is a twisting force really so
assuming you are encasing the whole stator in fibreglass matt
and resin you could go to a fair size and still be strong. Some
cars use fibreglass and are only a few mm thick !.
Your best solution is to mount some magnets on a plate and a
test coil with a known number of turns.....do some tests at a
set speed then do some paper number crunching.
#Post#: 5231--------------------------------------------------
Re: Newbies Questions - PMA Generators
By: maximoney1 Date: January 27, 2015, 5:46 am
---------------------------------------------------------
@ness
On my drawing board i have a design which incorporates two
stators of 36 coils each & three rotors with 48 magnets on each.
Thus although the magnets and coils are small, i was hoping to
make up for this in number, ie 2 stators thus giving 2 x 12
coils for each phase (or bring the output of each stator out
separately, giving greater flexibility?). I was hoping for less
cogging having a better distribution of magnets around the
diameter, less peaks and troughs between the magnetic flux
density and greater frequency of magnets passed the coils to
compensate for lower rpm turbine?
I had considered a single stator with 72 coils and a dual rotor
with 96 magnets on each. This pushes the diameter out quite a
bit and i wanted to keep each rotor backing plate a substantial
thickness for stability & strength properties, but that pushes
the weight up quite dramatically.
My main aim is to run a DC pump and a fridge compressor for
another design i am working on.....so effectively, my required
load is a fridge!
Thanks for your input.
#Post#: 5236--------------------------------------------------
Re: Newbies Questions - PMA Generators
By: maximoney1 Date: January 27, 2015, 7:08 am
---------------------------------------------------------
@cg
No mate magnets are 60mm x 10mm x 5mm. I can get 96mags for a
3phase configuration in a 600mm diameter rotor, but need another
100mm on top of this for bolts. I need to use a substantial
thickness of backing steel plate, for dimensional stability and
accuracy of gap, thus the increased diameter costs a lot of
weight, which, whilst i have substantial bearings, does ask a
lot of the turbine for early start up. Turbine dimensions i was
looking to work with were 3 x 3 meters(savonius/h rotor hybrid).
The magnets are neo's and at coil thicknesses of only 5mm,
should deliver a very capable flux density with a twin rotor
design and very small airgap(both the gap between the face of
the rotor/stator and total overall, through the stator).
Yes i am aware it would need to be done through a battery with
all the control gear that goes with it.
#Post#: 5238--------------------------------------------------
Re: Newbies Questions - PMA Generators
By: maximoney1 Date: January 27, 2015, 7:31 am
---------------------------------------------------------
@cg
It means the coil 'legs' would be 60mm long and thus a greater
percentage of the overall coil is under the influence of the
magnetic flux.
#Post#: 5240--------------------------------------------------
Re: Newbies Questions - PMA Generators
By: maximoney1 Date: January 27, 2015, 7:50 am
---------------------------------------------------------
@cg...lol mate, know the feeling re the coffee!
Working with my measurements, i can probably coax the coils to
6mm width & thickness, looking at how the magnet passes the
coils and the angles involved, which would potentially be the
difference between 64 turns and 100 turns in each coil....so
that could help a lot. Trouble is, experimenting with these
things can become extremely expensive once magnets get stuck in
place on rotors etc etc, so i'm still deliberating a 48 mag
configuration (on 3 rotors)at a rotor diameter of approx 400mm
or else a 96 mag configuration (on dual rotor) at a rotor
diameter of approx 700mm
Any thoughts yourself?
#Post#: 5244--------------------------------------------------
Re: Newbies Questions - PMA Generators
By: maximoney1 Date: January 27, 2015, 8:19 am
---------------------------------------------------------
@cg,
Thanks for the tip. I'm kinda wishing i had went for the bigger
more powerful magnets with the fixing hole through the centre so
that i could experiment to my hearts content :)
I'm now in the position of hoping guys like yourself, lynx, ness
etc can provide me with enough of the collective practical
experience to guide me through the black art...lol.
#Post#: 5255--------------------------------------------------
Re: Newbies Questions - PMA Generators
By: lynx wind Date: January 27, 2015, 1:01 pm
---------------------------------------------------------
There are two ways to move through the black art -
Study and design first utilizing a design that works - then make
any changes you think you want
Or, just jump in, spend money, try stuff, learn as you go
Both are fun
*****************************************************
DIR Next Page