Need the advise for the best 1.2 vdc to 5.5 vdc PWM

[Flash]

This is a follow-up to the previous question:


Cockroft Walton multiplier for three-phase alternator



I minimized the gap between the magnets and a coil, and used Germanium diodes for voltage doubler rectifier, and the result now is 1.2 VDC rectified minimum voltage. That, according to Nando comment, should be enough to use LVCMOS PWM. Any ideas which one to buy? Sorry for bothering, but I'm not sure I can find the best very fast. I was able to find this so far. This has 1.3 minimum voltage, close but I would prefer 1 VDC, just to make sure. On the other hand I may be able to increase the voltage if I use schottky diodes....


Thanks

[willib]

hi flash ,i guess rewinding the stator for higher voltage is out of the question?

[Flash]

The problem is that I winded it mysef and unfortunately I don't think I could do any better...

[willib]

What is your alt like ?

num of mags., and dimentions?

num of coils

wire size

outer dia of alt?

[Flash]

3 phase 'axial-flux' alternator.

6 magnets - Surface Field: 3490 Gauss; 1/2" x 1/4" x 1/8" thick, glued to the 5cm diameter circle metal sheet in flower shape.

Wooden 5.5cm diameter base with 18 ray 1.5 x 0.7 cm holes for stator coil (6 per phase).

1200 number of loops of #38AWG magnet wire per phase (200 per ray)

Gap between magnets and stator is about 2mm.

The design looks like this, although 2 times smaller...


1 phase ac voltage measured corresponds to the calculation by this formula  with 4 cycles per second:


Vmax = NARPB/2


Where:

· N is the number of loops of wire.

· A is the area enclosed by a loop of wire, in square meters.

· R is the rotational velocity of the magnets, in cycles per second.

· P is the number of magnet poles per cycle.

· B is the strength of the magnetic field of each pole, in Tesla.


and equals ~ 0.5 VAC

[willib]

You might want to try these people

their prices look to be better ..

http://www.magnet4less.com/ndfebmagnetblocks.html

if you made your coils smaller , and didnt overlap them you would get much better results , even with the magnets you are using

[Flash]

Thanks Willibur. That's my first alt, may be in the next one...

As to my question if somebody is interested, I was able to find also this. Manufactured by MAXIM, minimum input voltage 1.1 VDC.

[Slingshot]

Also have a look at www.magnet4sale.com

They are in the same town, but have different physical addresses.