Hi. I have read this very forum pretty extensively before asking these questions - thanks to all those who have posted, it has been very useful to me.
B Field--------
I understand this complex function of various things: air gap, rotor metal thickness, Strenth of magnets, thickness of magnets.....
I have two 40 by 20 by 5 mm N42's with a separation distance (air gap) of 20 mm.
From reading the posts I recal that after a distance of the length of the magnet the B Field = aprox 0.6 ?? but within the range it is a linear ramp to another number (I saw 1.2 T)
What is this second B Field for the scenario above & how does it change if i have one 40 by 20 by 5 mm N42 facing one 40 by 20 by 10 mm N42? (one thicker magnet)
- assume thick steel rotors
Stator cooling-------
I am thinking to drill small holes in the core of the coils after they are cast to let heat out - As this region vill be the hottest. I dont think it will make much difference structurally, but I am also not sure it will do anything thermally either. What do you lot think?
I am too poor to be buying aluminium powder, but I was think of wrapping some shreds of aluminium foil in the cores of the coils. The only negative I can think of is eddy currents, but if I only put them in the cores, will these be significant?
- - - - - - - - - - Finally - - - - - - - -
I am making a 8 magnet dual axial flux generator, with 6 coils for 3 phase delta. I am using 4x1mm steel sheets for each rotor & airgap of 20mm, using awg 22 wire. I am hoping to get 300+ watts out
Doing preliminary caclutions found on forum, for OC voltage of 14 & cut in speed of 250 rpm, assuming B field = 0.6:
The calculation say I need 100 turns per coil.
Does this all sound right? any help appreciated
Chendy