Another Lego alternator...
...work in progress...
And more DC volts from AC.
This alternator is based upon repelling magnets mounted in a non-magnetic stator as shown below.
The magnet rotor has 12 1"x1/4"x1/4" neo magnets... max thickness of rotor is 1/4" (~6.125mm)
The alternator will eventually have 2 stators each with 10 coils of 135 turns 28SWG enamelled wire.
The coils are aranged in a 5 phase configuration, with 2 coils per phase.
The idea being that the alternator will end up something like this;
The stator is formed of 4 layers of 2mm thick acrylic sheet glued together (plastic ply ;), which is then carved with small bit on a dremel. I found that once the bit had heated up (due to friction) that it cut real easy thru the plastic.
The coils were glued into place with gap filling CA glue, whilst being compressed. The result, an 8mm thick more-or-less-dead-flat stator with nothing filling the middles of the coils (cooling advantage :)
Mounted into my test rig, made of Lego, I soldered everything up.
The gap is under 1mm (1/24").
So far so good...
...A while ago on fieldlines there was mention of 'schottky diodes' having a much lower voltage drop... I rescued some from an old monitor (or maybe PC board... salvaged alot of components recently and forget).
...A good resource for identifiying 'rescued components' is http://www.alldatasheet.com
Could the advatages of a Schottky diode be utilised?
Yep :)
I hooked up a schottky diode with a couple of regular diodes to make a bridge rectifier (left) and put this on one phase... the regular rectifier on another.
And tested the open voltage output.
The center meter shows the AC voltage (4.87v), the left meter shows the schottky rectifier DC open volts (4.19v) and the right meter open DC volts using a regular rectifier (3.77v).
(BTW the schottky diode is rated 10A/200v)
The difference between the schottky diode setup and regular rectifier is around 0.4v no matter the rpm...
not alot...
...but using a 5 phase setup this equates to an extra 2v at any given rpm, worth thinking about for a lower cut-in speed and less wasted volts.
more to do and learn yet...
having fun :))
paul
