Maybe possible idea for duplicating effect of Holcomb and others

[citfta]

Hi Jim,
I also am pleased you are going to work on this project.  I spent many many hours thinking about what we could use to test out the idea of a virtual moving magnetic field.  I suddenly realized that an automotive alternator pretty much already had most of what we needed.  So I did my first testing and video just to see if you could even induce a current into the rotor coil.  So you can imagine how happy I was to see that it is possible.  I think the next step for all of us is to find a good way to generate that virtual moving magnetic field.  I do plan to build that mosfet esc circuit as soon as I can so I can look at the signals from it on my scope.  The hobby esc uses PWM with very short pulses and that won't work.  But if the mosfet esc generates nice solid pulses then we may have a winner.  We'll see.


Take care my friend from OZ,
Carroll

[bistander]

citfta,
I have experience with VFDs powering induction motors of industrial variety. These are full wave 3-phase bridge inverters running PWM to synthesize balanced 3-phase power at a carrier frequency of 2 to 12kHz. The load inductance of the stator does an excellent job at filtering current. Scope traces are pretty smooth. And they often operate in open loop control mode without speed or position feedback. Just a set ratio of voltage to frequency. Obviously, driving induction motors, they do establish a true RMF.

These BLDC drives or ESCs needing position feedback for commutation are a different story. But beware of ruling out PWM for the RMF. And a side note, PMSM will run from open loop VFD. Perhaps not optimal performance, but I have done it.

Ultimately you want to run as a generator taking output from coils on a stationary 'rotor', right? So position feedback is moot. But it may be possible to hack a RC ESC to run open loop in a V/f mode by supplying a pulse train in place of the hall sensor or something.

Just some thoughts.
bi

[Ufopolitics]

Hello to All,


Like I have mentioned before, that I wanted to make the Electronic Components Diagram (with Symbols)...and so, here it is.

And the reason behind is to try to understand better the way circuit functions, since we all know that Fet's are just like switches, or relays...where Source-Drain are the main conducting side, while the Gate works as the turning point for the switch Gate-Drain ON or OFF.

So, I have named  Q1, Q2 and Q3 as the 3 FETs, which Drain side are connected in the same sequence as Phases A, B & C, so, Q1,D1 (Drain1) is Phase A Output, Drain2 is B Phase and finally D3 is Phase C.
And so, all components connected to each Q, are also numbered in that order as well...for easier understanding.

The main point here is to find the Sequencing Modular Order...that I assume goes from Q1 to Q2 to Q3, then return back to Q1...(I believe through Diode 3, which goes from Q3 Gate, back to Q1 Drain)
That means to identify Q1 whole Module, including all it's surrounding components...which connects to Module Q2...and so on.

And once we have a full understanding of this easy 3 part sequencing, then we could move to more number of coils, switched by more FET's driving them...in order to build a more robust, Higher Definition Magnetic Field.

The way an Alternator Stator is wound, is very simple, where each circuit of coils in series goes for the whole 360º, but alternated in Start-End positioning at specific angles-distance.

So, it is easy to make (wound), say Six Coils, instead of just three...driven by 6 FETs...separated by 60º, instead of 120º...

Still, there is some way to get there...but I  know we all could, only if we work as a Team...to reach just one main goal.

Regards to All

Ufopolitics

@Citfta: If by any means you want me to move to another Thread, please, just say it...I know somehow I have crowded your Thread here, as deviated from your original great idea!!...sorry!!

[ariovaldo]

Beck to Holcomb system. I received one of the rotors that I ordered. the small one.
As soon I have time I will start to work on that. The stator is a 1 HP motor with four poles that will be driven by a small VFD that can speed up to 200 Hertz. It has 4.5 Amps as the limit.
The first attempt will be just one coil in a conventional winding.
any suggestion?

[citfta]

Hi UFO,
Your schematics are looking great!  I don't see your ideas in any way detracting from the purpose of this thread.  Your suggestions and helpful drawings are very welcome here.  I, like most people have only so much time and energy to devote to any project.  So with several of us working together we stand a much better chance of reaching our goals.
What program are you using to create the beautiful schematic drawings?  I switched to Linux about a year ago and still haven't found a good schematic program.  I spent a good part of the day yesterday trying different programs but before I finished a good schematic you had already posted yours which I liked much better than what I had.  Thanks again for your input.


Ariovaldo,
I think your idea of starting with one coil is probably a good idea.  What I have been doing is using a dual trace scope so I could monitor the signal I was putting into the stator coils and also what I was getting from the fixed rotor coils.  That will give you a pretty good idea of what is going on.  And of course some meters to measure the actual voltages on the stator and rotor.  So glad you have joined us and are sharing with us.


Carroll