If this is your first visit, be sure to
check out the FAQ by clicking the
link above. You may have to register
before you can post: click the register link above to proceed. To start viewing messages,
select the forum that you want to visit from the selection below.
UFO & Machine
Thanks for help with those numbers. I never would have found those without your help.
Dana
"Today's scientist have substituted mathematics for experiments and they wander off through equation after equation and eventually build a structure which has no relation to reality."
If I make a 4-pole rotor using magnets with the poles pointing outwards N-S-N-S........
then I can make a stator core using black magnetic sand & polyester resin.............
how many poles should I make the stator and how should I wind it so it becomes asymmetrically-wound?
I can drive this using Johnstone's circuit (but make it 5x or 7x drivers if that's how many poles are on the stator).
And I won't need a commutator for it.
What's your take on this configuration? Spinning magnets with the coils stationary as opposed to stationary magnets
and spinning coils + commutators.
If I make a 4-pole rotor using magnets with the poles pointing outwards N-S-N-S........
then I can make a stator core using black magnetic sand & polyester resin.............
how many poles should I make the stator and how should I wind it so it becomes asymmetrically-wound?
I can drive this using Johnstone's circuit (but make it 5x or 7x drivers if that's how many poles are on the stator).
And I won't need a commutator for it.
What's your take on this configuration? Spinning magnets with the coils stationary as opposed to stationary magnets
and spinning coils + commutators.
Thank you!
Lester
Hello Lester,
So, You want to make an Asymmetric Brush-less Motor...
First, the rotor magnets you have displayed there are round, small...I would rather use rectangular curved magnets,closer to each others since they have a wider magnetic spectrum coverage...and no big empty spaces between them.
The Concept to rotate them could be similar to the Induction AC Motor...but DC. For that You have to Electronically create a Progressing Current, but based on a Square Wave instead of the AC Sine wave...
The existing Brush Less DC Motors Controllers do that with a Three Phase Square Waves Design that are Off by a Dead Time between them
like the picture below:
[IMG][/IMG]
What makes the actual Brush-less DC Motors Symmetric, is the fact that their Coils are CLOSED and classified into Two different type of Modular Windings...
1-The Star or Wye Winding
2-The Delta Winding
[IMG][/IMG]
The Commutation occurs completely by electronic switching of their Phases Alternatively in a sequential fashion that produces a rotation on the permanent magnets armature.
But You could do it also with Open Coils based on the Spiral Set Up I have displayed on My Motor Design...now the number of Poles depends on the number of Rotor Stators...they must NOT be equal, and typically the Rotor have more poles than the Stator, making it "Unstable" to find a particular "Rest Position". So, if you use Four Poles at rotor...there should be no more than Three Stator Poles.
The complications comes when Motor Starts...it needs a guide to always follow same direction when Sequential Square Waveforms are applied to Stators...so they either need positioning sensors, that could be Hall Effect Transistors...or by sacrificing one of the Phases to "Echo" back to processor the Coordinates Position related to Stators...then the other two phases start properly to achieve same rotation sense. But Motor will work only on Two Phases.
So, getting rid of the mechanical brushes will demand that you go very deep and precise into the design of the Electronic Switching System Design...
Principles for the Development of a Complete Mind: Study the science of art. Study the art of science. Develop your senses- especially learn how to see. Realize that everything connects to everything else.― Leonardo da Vinci
If I make a 4-pole rotor using magnets with the poles pointing outwards N-S-N-S........
then I can make a stator core using black magnetic sand & polyester resin.............
how many poles should I make the stator and how should I wind it so it becomes asymmetrically-wound?
I can drive this using Johnstone's circuit (but make it 5x or 7x drivers if that's how many poles are on the stator).
And I won't need a commutator for it.
What's your take on this configuration? Spinning magnets with the coils stationary as opposed to stationary magnets
and spinning coils + commutators.
Thank you!
Lester
Hello Again Lester,
There could be a simpler approach to achieve this...
But it will require some good craftsmanship...
A while back, I displayed an old Patent that I kind of improve...and it is about Polarized Reed Switches.
[IMG][/IMG]
You could make them with very small neo's and thin copper plates. They will be set at Stator side, and will close-open depending on Rotor Magnets Positioning...activating/triggering the right FET Channels to start rotation.
I recommend you start playing on a small number of Poles set first...as it would be your "Modular" set to scale up after you come up with a suitable design.
Now, the reed switches magnetic strength should NOT be greater than Rotor Permanent Magnets Strength or Coils Electromagnets Strength ...or it will lock Motor, or will create a big magnetic drag...They are supposed to be "light"...but able to trigger under different field polarities...whether open or close circuit...
Now you could do as many FET Channels as Your Microprocessor will output (Arduino Nano will do like 13 or 14 Programmable Channels...)...normally it is easier to trigger N-Channels...so Your Source Positive will be connected to all coils as a common end.
Hope You understood me well here.
Regards
Ufopolitics
Principles for the Development of a Complete Mind: Study the science of art. Study the art of science. Develop your senses- especially learn how to see. Realize that everything connects to everything else.― Leonardo da Vinci
Hmmm! Brushless design!
1. Can we harvest from these coils by diodes like in your first thread with pulsing coils?
2. Very similar to car alternators. what can we do with them?
Experts spend hours a day in order to question their doing while others stopped thinking feeling they were professionals.
FYI: Just 10 minutes before I got my first data base errors for today and now the forum behaves very slowly. This might be my last post for today (9:00 PM in central Europe)
JohnS)
In that case it's a simple matter to make the WYE connection asymmetrical by adding 3x FETs at the winding junction. I can drive those FETs with small toroid transformers, one transformer for each FET that's on the battery's positive terminal. The capacitor (C1) keeps the FET turned on even if the pulse duration is long.
The motor winding's output diodes can power another load or go back to the battery. Also, the intrinsic diode within the FETs will provide charging for the battery, if it will spin fast enough.
Timing-wise, a metal vane + hall switches would be easy to make and fully adjustable. Fixed pulse width using LM555, or, use the width of the metal vane to set the pulse width.
Starting & rotation direction: I'll just give some help using my fingers for now.
Sorry to distract from the main topic and thanks again for your reply!
2. Very similar to car alternators. what can we do with them?
Hi John,
The rotor on a car alternator has some winding also. I've seen someone replace that rotor winding with a doughnut-shaped magnet from a speaker but I don't know if it's easily done. Hmmm!!!!
Timing-wise, a metal vane + hall switches would be easy to make and fully adjustable. Fixed pulse width using LM555, or, use the width of the metal vane to set the pulse width.
High Lester,i love physical, mechanical, timing, shaft mounted, converted to electronic signal.
Of course a quantity buy makes them very affordable.
The data sheet is on their site and if you happen to be designing a circuit to use them for pulsing mosfets, it would be greatly appreciated if you could share it with me.
The data sheet is on their site and if you happen to be designing a circuit to use them for pulsing mosfets, it would be greatly appreciated if you could share it with me.
Just a few initial results from my converted Johnson, 3 pole motor.
The motor negative terminal was connected to the motor gen positive terminal.
I swapped the run and charge batteries over at approx each hour.
Total run time 4 hrs 15 min. Amp draw about 750mA.
Batt
1 2
12.13v 12.15v start voltage
11.88v 11.71v end voltage after resting
So overall drop of 0.69v
What is interesting is that the motor only gets pleasantly warm to the touch, as compared with the RS motor, that for me , was hot.
As UFO had posted up the self runner diagram, I thought I would connect up my motor and generator and see what happens – as you do! besides discussing with someone earlier in the day the possible need for limiting the amps from the cap bank. My generator puts out about 90v, so I fed that into 2 x 100v caps, total capacity of 11,300uF. On making the switch from the cap bank to the motor generator section, an immediate increase in RPM was heard and a bright blue flash/bang from one commutator end of the motor, with something bright flying out of one of the slots in the motor case.
So what have I learnt? Restrict the amps from cap? (use pulsing/inductor). Could do with a heavier flywheel because the motor rotor is quite light, and as the bearings are solid rather than ball bearing, I think the drag of the motor bearing will be a limiting factor.
Anyway next test with the motor will be with PWM – once I get the circuit going.
Last edited by john_g; 01-14-2013, 09:23 AM.
Reason: forgot some details
Hi John,
The rotor on a car alternator has some winding also. I've seen someone replace that rotor winding with a doughnut-shaped magnet from a speaker but I don't know if it's easily done. Hmmm!!!!
Yes well.
For reworking the rotor -> heavy tooling required (refurbishing shops use them as pull and press tools). Apart that I do not know if the pole shape ist correct.
Else: I feel machining a new rotor will be perhaps a much more easy approach.
Is it essential to have more poles at rotor? Or is it essential to have different count of poles?
We do not want to deviate the thread but it is from time to time very helful to look "behind the next hill" in advance.
JohnS
Experts spend hours a day in order to question their doing while others stopped thinking feeling they were professionals.
Hey Machine, just watched your vid again, and MAN, that's no Princess trying to get out there, it's more like a very strong and phisically fit QUEEN, who doesn't mind digging in and helping her subjects do hard work.
Comment