Electric Motor Secrets

[mbrownn]

Those scope shots look exactly like what the friend of mine is getting. Im sure he will be interested. I call that the mwm wave, very similar to the kromray converter.

[Robert49]

Hi Mbrown.

I decided to ignore the collapsing spikes and am no longer collecting the generator function.
I ran the motor at 140volts and it went to 3362 rpm with only 0.18 amp
or 25.2 watts. It does have a lot of torque.(not measured, just felt)
Look at the position of the driving pulse.
Here are some scope shots.

Robert

[Robert49]

Update

Hi
I made more precise measurements.
The motor ran at 166volt 740milliamps 3417rpm no load.(122.84 watts)
Loading the shaft 166volt 900milliamps 2500rpm.(149.4 watts)
It takes quite a bit of pressure to slow it down.
I have to capture the spikes from the collapsing fields which are not that high since there is no iron core, otherwise the motor jams. But by doing that, i'm also capturing one phase of the generator voltage and both are dissipated in a 40watt light bulb fully lit.



Robert

[Robert49]

Hi Robert,

Thanks for the further details. Sorry I do not get what you mean on counter emf? For me it means just the (unwanted) induced voltage in the stator coils whenever the rotor magnets are in motion. And if the induced voltage is 80 Vpp, then is not it just the counter emf? I may misunderstand something.

Can you recall when you loaded the shaft of the motor, the input current went up accordingly?

Well, 100 W output is very good indeed when the input is also 100 W. Can you recall the DC input voltage amplitude you gave to the motor and how you measured the output power?

Thanks, Gyula
PS: From tomorrow I will be away for 3 days.

Gyula, you are right about the counter emf being a generator effect but in this motor it is desired.When the magnets pass through the coils they first generate voltage in one direction until they are dead center where the voltage is at zero. Then the voltage rises in the opposite direction. I pulse the coils in repulsion mode at the zero voltage position or very close to it which eliminates almost all the effect of cemf .At least that's my theory.

As far as loading the shaft and the effect on input power, it is minimal and due to the pulses being longer as speed decreases and on this motor measuredin milliamps. At 100 volts input, the motor uses 490ma and when loaded to half speed it uses 690ma.

I recall putting 100 volts 1amp in and I had a 200 watt light bulb connected on the output.Then I measured the amps and voltage on the bulb.

Hope this clears up things for you

[gyula]

Hi Robert,

Thanks for the further details. Sorry I do not get what you mean on counter emf? For me it means just the (unwanted) induced voltage in the stator coils whenever the rotor magnets are in motion. And if the induced voltage is 80 Vpp, then is not it just the counter emf? I may misunderstand something.

Can you recall when you loaded the shaft of the motor, the input current went up accordingly?

Well, 100 W output is very good indeed when the input is also 100 W. Can you recall the DC input voltage amplitude you gave to the motor and how you measured the output power?

Thanks, Gyula
PS: From tomorrow I will be away for 3 days.

[Robert49]

Hi Robert,

Thanks for showing this interesting coil shape. Would be curious what voltage amplitude is induced in the coils when the rotor magnets are spinning (say by an outside prime mover) at an rpm identical to the normal running motor rpm?
MAybe you have not checked this, and in case it is cumbersome to do I understand it of course.
I ask this because I figure such coil shape may help minimize unwanted induction (i.e. generator effect, counter emf) from the rotor magnets while still performing fine to give useful torque to the rotor. Maybe the mass of the rotor could further be increased to have an energy storing flywheel effect from the rotor too.
One more thing: you put the (for now) words into brackets at the end of the sentence, maybe indicating there is a possibility in this setup to make it a self runner?

Thanks, Gyula

HI gyula I forgot to mention that the magnets have to be north-south south-north etc for this to work. The coils are bi-filar and all connected in series.
One winding is pulsed in opposite direction to the other.
At 1500rpm the voltage induced is 80volts peak to peak. I believe there is no counter emf on this motor.
(for now) is because when I made this motor years ago, I remember showing one of my friends the results: 100watts in 100wats out. I did not try to loop it back.

Thanks

Robert

[gyula]

Hi Robert,

Thanks for showing this interesting coil shape. Would be curious what voltage amplitude is induced in the coils when the rotor magnets are spinning (say by an outside prime mover) at an rpm identical to the normal running motor rpm?
MAybe you have not checked this, and in case it is cumbersome to do I understand it of course.
I ask this because I figure such coil shape may help minimize unwanted induction (i.e. generator effect, counter emf) from the rotor magnets while still performing fine to give useful torque to the rotor. Maybe the mass of the rotor could further be increased to have an energy storing flywheel effect from the rotor too.
One more thing: you put the (for now) words into brackets at the end of the sentence, maybe indicating there is a possibility in this setup to make it a self runner?

Thanks, Gyula

[Robert49]

Another crazy idea

Hi guys

This is something I made about five years ago which is worth sharing for it's weirdness.
This motor has no core, just windings and magnets and the magnets act as core and rotor. It is running in repulsion mode but can be used in attraction or even in attraction-repulsion mode depending on the timing.
I had great results with it when I made it, but took it apart cause I needed the shaft, bearings and plates for another project.
I just rebuilt it but can't remember exactly how I got these results but am playing with it for now. The motor runs and generates power but it is not a self-runner. (for now)

Robert

[Robert49]

Small update!

Special thanks to Peter Lindemann for his help.

Peter said that a bar shaped rotor creates a lot of drag so I had it modified and while at it, had slots made and inserted magnets in there.
They are 0.125in x 0.250in x 1in , magnetized through 0.125, three per slot.
The stator poles are at 10 degrees and the magnets at 12 degrees.I also modified the drive circuit to capture the pulses.

This setup gave five charging cycles per power pulse, or 90 charge cycles per rotation: too much!! The drag is awfull.

I will try with fewer magnets later on but for now , I removed all of them.
When the rotor was bar shaped, maximum speed was 6500 rpm. With the modified rotor (without magnets) , maximum speed reached 9800 rpm.

Thanks and good luck to everyone.

Robert

[Robert49]

Hi friends.

Just a test I had to do. I added magnets on the rotor, 0.125 inch thick, magnetized through the 0.125 inch.
I use coils 1-2-4-5-7-8 as drive coils and 3-6-9 as generator coils.
If I short the coils, the speed and the input power remain the same and if I drive a dc motor with it, same thing.
If I light a bulb with it, the amps go up slightly and the rpm goes down.

This setup was just to see the effect of a "sideways" magnetic field in a generator design.

Robert

[SkyWatcher]

Hi infinion, the standard core you show are too closely spaced together.
The stator pole would be pulling on each armature pole and preventing rotation.
It looks like removing every other armature pole would work fine, for a total of 5 armature poles.
I have built my own crude attraction motor in the past and have seen how it functions.
I have a motor here from a home furnace blower, that i will open up and see if it can be used for an attraction motor.
peace love light

[Infinion]

Why Shave Rotor Iron Core to a Cross Bar Shape?

Greetings to all! I decided to register and post as I did not see any question specific to my own in this thread and had to ask (for my own sake and for adding to this great repository on the energetic forums).

With regard to the Series 1 DC motor, its modification involved removing the rotor windings as they were unused deadweight on the rotor, and shaving the iron core to a shape resembling that of an iron bar.

I understand that maximizing cross-sectional area of a permeable metal is key for core design, but I didn't understand why the Series 1 had several of its armature core's pole pieces shaved away. Was it for the sake of demonstration, to show the operation of a rotary attraction motor with a simple and intuitive core geometry, or was there another consideration favoring its removal in the design?

for more context:
A standard armature core will look like the one in the image below, with laminated stacks of subdivided soft iron or steel sheets to minimize eddy current and hysteresis losses:



the Series 1 armature core was modified to be shaped closer to a cross bar, essentially having 4 subdivided rotor core pole pieces per stator pole:

[Robert49]

Hi Robert,

The .0025 inch air gap for your new rotor is very, very good, hopefully a mechanically very stabil and robust structure accompanies it. When you found the higher rpm with a bit more torque vs the previous air gap size, did you notice any change in the input power? Just curious, I assume you had an ampermeter in series with the supply but if you did not, no problem.
Hopefully the torque tests you are going to do will reveal results you expect from the setup.

Gyula

PS This guy (that_prophet) litters most of the known forums with his long posts on his "brainchild", appearing out of nowhere in any thread. He has been active with making such posts for some years now. Such is his life...

Hi Gyula.

This motor is a very sturdy one with a 1.175 inch diameter shaft .It takes about the same power to run it. I ran it at 200 volts and about
1 amp and it turned at 9000rpm .
The bearings are noisy and they need to be changed. When Iput a load on the shaft the amperage barely changes.

Cheers

Robert

[gyula]

Hi Robert,

The .0025 inch air gap for your new rotor is very, very good, hopefully a mechanically very stabil and robust structure accompanies it. When you found the higher rpm with a bit more torque vs the previous air gap size, did you notice any change in the input power? Just curious, I assume you had an ampermeter in series with the supply but if you did not, no problem.
Hopefully the torque tests you are going to do will reveal results you expect from the setup.

Gyula

PS This guy (that_prophet) litters most of the known forums with his long posts on his "brainchild", appearing out of nowhere in any thread. He has been active with making such posts for some years now. Such is his life...

[Robert49]

Hi people.
This guy has absolutely no idea how magnetics work
If it were that simple, it would have been done by the cave men.
Maybe he should start a new thread.

Have a nice day Preacher.