Simple to make Hilden-Brand style motor

[Honk]

Great Ron.
Now you can see what you are facing when energizing the coils in your motor.
The resistance is of minor importance when pulsing an electromagnet.
All that matters is the inductance and less inductance give you a lesser magnetic field at faster response time and vice versa.
Keeping the resistance low is of course good to help keep the windings cool but the resistance doesn't really affect
the response time very much.
What you need is good core material with low eddy currents and hysteresis. Any solid iron stuff is almost useless.
The eddy currents is best described as short circuited current loops within the core. Thin laminates decreases this.
And the hysteresis is the difference of what you put in to magnetize the core and what you get back as inductive kickback.
Both these losses increase by frequency and is stated as loss/lb or loss/kg at various frequencies in the material spec.
Solid iron has the worst eddy currents and hysteresis loss among materials and should be avoided if possible.
To find out if your coil can handle your pulsing please use the Inductor Transient Calculation page.
http://www.overunity.com/index.php?topic=2222.msg132830#msg132830
I use this very frequently and without it I would be totaly lost.

[wizkycho]

Introducing another air gap does nothing but to lower the material response to the magnetizing force.
In everyday electronics air gaps is introduced to decrease the sensitivty of the material to avoid saturation.
The more or larger air gaps, the more coil power is needed to obtain the 1.5T you desire in the magnetic circuit.
This is nothing remarkable. It's well known physics. Any electronic stuff you own is based on this principle.
The B/H curve above is only valid in a closed circuit with no airgaps. In a motor with 0.1mm gap the B/H curve is
slightly flattened out and the saturation point moved down the Amp/meter line, not much but clearly measurable.

All !

Inserting another air gap could help equalize magnetic resistances of two paths, coil that way would need less energy to increase that resistance a bit more than resistance of alternative path. that gap doesn't have to be air - could be material with lower satturation point...
many ways to ease the input energy...If air is used by some calculation and expirience from another researchers in MEG-olike setups
this added gap should be 1/2nd of gap between driver-stator and core. even back Lenz bends (MEG-like) setups and has to be stronger to
neutralize main cause field.

It is in anyway very worth to try if alternative path (to rotor and back) is long and can not be well designed ("big" airgaps - rotor wobling a little), and meassurements doesn't show FE.
This gap could be main thing (depending on setup) in efficient switching magnetic field from permanent magnets.

Wiz

[wizkycho]

Nali !

Your core is cut to half where the coil is so seems to me that original path could have too high mag.resistance.
This is easily to test - see if, with added magnets (on both sides) and no current, rotor spins freely. and doesn't wan't to stick to stators.

If rotor wants to stick to stators - mag field doesn't close through coil(when off) completely. I think it should close completely (not genesis like) because those motors of yours are small and magnet field, if not closed properly, easily will "touch" rotor even not overlaped - especially
if one magnet pair is N-S and another is S-N....and rotor is allso high permeability.
This could be reason why RPMs droped !

Allso I would go with weaker magnets - 2/3 value of where satturation starts (0.8- 1T) - cause magnet fields must travel with coil field

besides I think that RPMs doesn't drop so much (few rpms) but current drops substantially - You have only two drivers
and current droped to half. with more drivers (four) curent drop will drop not half but probably to 1/3th

all other experiments with high rpm (beyond 1000) are not good I think for first FE results...maybe later on...

all the best !

Wiz

[wizkycho]

@Nali !!!

wonderfull videos... much to leran from them

I'm watching your videos over and over again and after some time I tought that there is one crucial thing that should be tried:
(except for checking flux leakage and complete flux closing - my previous replay to You)

- lower down RPM to 800 RPMs , but not with mechanical friction on shaft, but with lowering down input voltage (input energy).
this is principle of valve - (1.) low input energy pumping (2.) strong magnetic flux of PM (this is must procedure). And not (1.) 144W of input doing (2.) friction on mechanicall break (3.)...
- then add magnets

What happens ?

Please Can You do video of this ?!! 

I expect RPM should rise significantly (not just few RPMs but huge difference) - due to RPMs input lowers further  

then would be nice to place some generator on shaft....

Wiz

[wizkycho]

@Nali

...thinking further that start RPMs w/o mags should be as low as it can
and then put magnets.
that way we would see what is minimum input energy that we have to produce to start the machine.
and choose/construct gen in accordance. since eff. genearators are not that easily to find - maybe some small wattage is enough to close the loop and make proof. and after that intensify research in finding maxes.

again many many thanks for those well done and documented videos.

Wiz