Maybe possible idea for duplicating effect of Holcomb and others

[bistander]

....
I did one more thing before dismantling that system.  I turned the slip ring current on the driving alternator up to several more amps to see what would happen.  I only ran it like that for a short time because of the heavy load on the scooter motor.  When I did that with the second alternator free to turn it took off like a regular motor and reached a pretty high speed very quickly.  I took a quick glance at the meters and the scope and there was barely any voltage being generated in the slip ring circuit.  I think this proves the induction into the slip ring circuit is coming from the moving magnetic field because when the rotor got up to close to the same speed as the moving magnetic field almost all induction stopped.  A quick glance showed less than a volt being generated as compared to 30 volts or so when locked even though the 3 phase field was much stronger.
...

Thanks for running that test and reporting. Results are as I suspected. It would not reach synchronous speed because as an induction motor it needs slip (difference between stator frequency and rotor frequency) to induce torque producing currents in the rotor (steel in this case). This slip frequency with no mechanical shaft load is very small, a few Hz at most. Therefore that frequency (and rate of change in flux) is what the shaft concentric rotor coil sees, hence the low voltage.

Great test.
bi
ps.
I like experimenting with the hobby BLDC drivers and breadboard FETs you guys are looking at. But those power signals (3-phase) differ considerably from a balanced true 3-phase source. So the resultant stator flux is unlikely to be a clean constant magnitude traveling magnetic field. More likely a sequence of pulses.

[Feb2006]

I think you need to watch all the videos from the beginning so you will understand what we are experimenting with.  We are doing basic research on the idea of making a virtual moving magnetic field and the effect it might have on generating power.  The ESC I used uses PWM to generate a sort of sine wave.  Because the PWM pulses are so short they don't have time to generate a field into the slip ring coil because the impedance of the slip ring coil is too high for that short of a pulse.  An ESC such as the one in the second video UFO linked to probably has a simple on and off pulse without the PWM.  If that is the case then it should be able to generate a moving magnetic field like we are looking for.


I hope this helps you understand what we are doing.
Carroll

https://howtomechatronics.com/how-it-works/how-brushless-motor-and-esc-work/


"So, when the moving magnetic field of the rotor pass through the free coil, or the one that's not active, it will induce a current flow in coil and as result a voltage drop will occur in that coil. The ESC captures these voltage drops as they occur and based on them it predicts or calculates when the next interval should take place."


No moving or wrong moving magnetic field results in wrong intervals.
The second video  half bridge ESC  can work a fuii bridge ESC that not predicts or calculates the next interval can also work.

picture is full bridge, half bridge has only one on and two off alternating.

[Jimboot]

Thanks for running the tests Carroll. I went a salvaged an alternator today. Here is another of Zafers vids where he shows part numbers and circuit. https://youtu.be/geT94tV-xBM

[citfta]

Hello Bi,
In the last video I posted I show on the scope that the RC ESC does use PWM or very short pulses to create a  simulation of a sine wave and therefore does not make a good source for our virtual moving magnetic field.


Hi Jimboot,
Good to see you here also.  I do plan to  build that MOSFET controller so the video is a help.  He does a good job of showing the actual build with part numbers.   But I need to draw that out on paper as a real schematic is the way I look at electronics.  I spent so many years troubleshooting circuits that is just the way my old brain works.  I just haven't take the time yet to draw it out.  I do think his circuit will probably give us a good signal for a virtual moving magnet field but only testing will prove or disprove that.


Take care guys,
Carroll

[Ufopolitics]

Hello to All,

Well, I am very glad that I have triggered some interest from my previous post...

Please, let me first thank Feb2006 for clearing up something that I totally forgot to mention on my previous post:

The ESC we use here MUST BE a Sensorless or Hall-less type!!
Now, some ESC do not have an extra connection for the sensor, but uses one of the Phases at each interval of time, where that phase goes "inactive"...and these ESC Types are NOT good for the effect we need to achieve, which is a CONSTANT Rotating Field effect from the 3 Phases working at ALL TIME!!

@ Citfta, excellent testing my friend!!, basically your description and results about your first test, without the ESC...plus your conclusions that Rotor must be stopped in order to get max Output.

Now, on the second video with the ESC, I suggest you make a "rig" to be able to see the scope signal without all the scrambling you are getting...and again, it would be much better seen on a 4 Channel Scope....but I know you do not have one working...However, this will work as well just for one signal of the 3.

I took two images out of the link that Feb2006 posted: https://howtomechatronics.com/how-it-works/how-brushless-motor-and-esc-work/
And upload them here...

So on Image #1 He uses 3 resistors from the three phases and attach them together to create a "virtual common point"...as I suppose the resistance is supposed to be the same or approximated to each Coil resistance on the Motor (or in our case, the Alternator Coils).
Then attach just one of the gator clips to that common point (since it is just all clips are the same ground point for the scope).

On Image #2 You guys can see the three clean sinewaves seen at the Four Channel Scope (btw, very similar to mine, but mine is a DS110, not a DS105)

Anyways, Yes, I particularly like much better (like I mentioned on my previous post) the 3 FET Circuit that Zafer built...just because it seems more suitable for an Alternator set up like we will have...plus it uses that common point to regulate and control the three sinewaves.

Now, IMHO, if it can turn the Energized Rotor, even with a very small voltage from a 1.5V AA Battery...it does Generates a Rotating Moving Field.

Plus, if You make a simple test, I know it will also spin a N/S Radial Magnet inserted at center of Alternator Stator, mounted on a spinning shaft.

Now, with the ESC it does NOT generate the "Induction Motor Effect" which will turn a non magnetized steel rotor (like in Ctfta first videos, generated by the Alternator Generator)...it must be a magnetized Rotor here.

Take a look at Pierre Cotnoir setup, He uses a Magnet to verify the Rotating Field on his Six Poles rotary Field Stator...not a plain piece of steel as rotor.

Regards to All

Ufopolitics