Why do two drive coils draw less power and create more RPM ?

[Magluvin]

Three of the coils are 800 turns bifilar, trigger wire is finer than power wire, can't remember gauge maybe trigger around 0.25mm and power 0.35.

The fourth is about 600 turns of same.

My generator cores arrived today and they are the wrong bloody size, my fault, i was going on bolt diameter not shield diameter ...

Here is pic :

http://qvision.pwp.blueyonder.co.uk/setup.JPG

I have a callout so won't be back until 10pm.

Hmm  maybe if trying the diodes in the other direction doesnt work, then maybe there is something up with bifi that this doesnt work...  dunno   I cant fathom why.

Mags

[DeepCut]

Ye i was thinking the same. I have a pound of the power wire i used on those coils left, tomorrow i will wind some coils with only that and make them all exactly the same.

[Magluvin]

Well   something simple to try.  Undo the bifi and run the coils separate strands in parallel.  If you only have 3, try those in unbifi mode, in series. 

Your power in will go up and rpm. But it gives you something to try with what you got.

Maybe you get over 2000 rpm. maybe more than .97w but then add the diodes. Just to see what you get as compared to before.  Be careful at any high rpms. At least goggles.   ;]

Was thinking, the possibility that the diodes kept the coil running too long, due to the config of the coil in this case.
If you have a scope and possible way to shorten the pulse to the bifi, its very posssible that you could use a lot less power and the freewheel has time to stop before the next mag comes and is not forcing the rotor in reverse, as would be if the coil is still spinning.

Sounds nuts, but if you have those diodes in the right way, it is very possible that the flywheel is going still, when the next mag is approaching and cause slow down. And higher current, cuz the thing is still spinnin, new current can flow more and easy from the source.  There is no git up lil doggie on the coil.  No impedance to kick into a gradual current increase.  Its already goin.  Gotta scope this if you can. 

This is all theory, but they are things, clues that you gave me, that I question, and these are possible answers.  ;]

Just to get some experience with it.   ;]

Im going to try some things while I have my coils up.

But try the parallel on the bifi's  If you have a way to lower the on time, this will reduce input. Then diodes. I suggest 600v n up and probably a couple amps to try.

Mags

[Magluvin]

When I said undo the bifi, I just mean to undo the ends that make them series strands and make them parallel.
If its not a hassle.  ;]   may even lower the in V.

It will give you an idea of how much you will save on input as compared to a simple pulse situation.

Now would ya think that you are getting more out of the motor if the freewheel diode allows additional push on the rotor that the input pulse alone?  Im not saying its free, yet ;], but its something that just gets wasted otherwise. 
Mags