How to determine the limits of a coil / magnet configuration

[JW]

I remember discussing this with user- Flux years ago before he died of cancer. search for Flux's posts.

[brandnewb]

BTW Mary,

even though cogging will always be there to the extend of physics.

I have managed to make it unnoticeable in terms of additional vibration and/or reduced rotation of magnets.

Whether testing open or closed circuit.

So my hypotheses of reducing space between coils will help negate the issues with cogging hold up to scrutiny thus far.

Now here I start my little panic attack again
Why can't I get the magnets/coil arrangement to show some kind of breaking force when in a closed circuit loop?

Should I short all the coils in parallel or each coil shorted separately?

[JW]

There is a thing called "fade" and its relative to speed, how do you deal with this" bigger magnets. However using more weak" magnets is not the answer.

For god stakes man do your experiment's with like a neo 1/2in thick. Although you cant thread tap them but you can egg shape them if they are ground that way.

Most of us here expect losses. you don't think that way   

[brandnewb]

ok I understand now.

all these field readings I have been doing amount to nothing impressive.

I almost got my self there fooled for a little while as I thought that I could display some rather intimidating results.

But ok, I stand corrected.

Now please define a "better bigger stronger" magnet. other than dimensions how was it determined to be better. And I would love to see those magnets in practise.Would indeed be cool.

Now if it turns out to not be easy to show something DIY that is more powerful then what I am trying to do then I can fully understand that.

I just am hoping for something to look up to for inspiration,

[JW]

treat NIO magnets with respect when you have them. Often when they send them to you, each magnet has a corrugated type cardboard around it. Then shielding' them for shipment.

Do a fieldlines search using hard drive magnets.

yes its weaker power but they do work, at least 15 people have made prototypes with just the magnets from hard-drives   

 

[JW]

This is why the database is so important.

https://www.fieldlines.com/index.php?topic=138725.0

[brandnewb]

understood sir!!

I will admit that I might have not taken a good enough look but the link you gave, although interesting, seems no where near as frightening as what I want to end up with.

But again, I am still rather novice so perhaps I just was not able to see the finer details.

Anyway JW, lets be cool ok? I hope that once I am done I have earned your appreciation.

maximum respect.

[brandnewb]

Now even though I am scared I am running into a dead end because I can't seem to be able to demonstrate drag or braking ability.

This does not deter me from plowing through trying other setups.

Now we are at an inner radius of 300mm rather than 600mm.

And the repelling magnet configuration is back as I fear that when placing these magnets traditionally then most of the field will be diverted between adjacent magnets rather than through the coils.

Now my hypothesis is that this can never happen in a repelling setup.

Even so at around what I had hoped to be 2.5Hz things are not looking to bleek.

[brandnewb]

what I do not yet understand though is that I do not see this sudden dip to 0 that I was expecting in between opposing fields.

I am guessing that the electrons in the copper wires are able to also pick up on fields that are not ideally perpendicular.

[brandnewb]

I do not mean to bump this thread.

But just to be sure I am asking for advice.

Now if I am unable to somehow measure/demonstrate a breaking force of the PMA then that means there is no chance that it will produce any actual wattage while in operation?

I am rather unsure on how to proceed at the moment. So I am going back to repelling but this time with 192 magnets on a single disk and see if super narrow coils on both side of the magnet disk can provide a breaking force.

[Mary B]

what I do not yet understand though is that I do not see this sudden dip to 0 that I was expecting in between opposing fields.

I am guessing that the electrons in the copper wires are able to also pick up on fields that are not ideally perpendicular.

AC crosses the zero line every cycle, as your magnet polarity changes over each coil

[brandnewb]

Yes indeed Mary,

But given there, based on my current understanding of the theory, is no field between opposing/repelling fields.

I was just surprised to not see this tiny void. I will try increasing the sample rate. Perhaps now it is set too low.

[Mary B]

Yes indeed Mary,

But given there, based on my current understanding of the theory, is no field between opposing/repelling fields.

I was just surprised to not see this tiny void. I will try increasing the sample rate. Perhaps now it is set too low.

You will not see a square wave, it will be a distorted sine wave. How distorted is dependent coils and magnets... I can think of one turbine on here that produced a good sine wave... yours is not bad at all for waveform... you may see a flat line between waves in some machines depending on build and speed of the rotor, slower you go the more of a chance of that. As a magnetic field reverses polarity a coil gives off reverse EMF, that is cogging and affects waveform. Worst case cancels some of the sine wave and results in no wave aka 0 volts and a flat line on the scope.

Make sure you set coupling to AC, in case there is any DC component there from a bad solder joint(can act as a rectifier... I have a story about that but not for here!) etc...

[MattM]

His distortion comes from that little bit of twist in the coil.  It will smooth out a bit as you complete your ring stator.

[JW]

This why I mentioned the Oscope is not a good thing to start with at the armature level. Look at these waveforms from my link.  HA HA, we got techadmin with RMS voltage way back.

https://www.google.com/search?q=ac+waveform&oq=AC+waveform&gs_lcrp=EgZjaHJvbWUqBwgAEAAYgAQyBwgAEAAYgAQyBwgBEAAYgAQyBwgCEAAYgAQyBwgDEAAYgAQyBwgEEAAYgAQyBwgFEAAYgAQyBwgGEAAYgAQyBwgHEAAYgAQyBwgIEAAYgAQyBwgJEAAYgATSAQoxMTc2M2owajE1qAIAsAIA&sourceid=chrome&ie=UTF-8

edit sp ck   [spelling check/correct there can also grammar]

[JW]

 the thing is your thinking stator and not armature (if you will) nothing you have described shows complete  to a magnetic circuit.,

[brandnewb]

finally I think I figured out how to create a breaking force/ why I was not able to demonstrate that yet with shorted coils.

That is probably because the coils I shorted thus far while testing for that do not generate any magnetic field in the x axis where we need it.
The y axis I did not test but the z axis did have a field where we do not really need a field as it will lead more to bumping magnets than breaking magnets.

Now if only I could change the Hz going through my variac from 50 Hz to what ever it is I am aiming for. It might also turn out that low Hz PMA's are not really well suited for generating opposing/attracting fields to the magnets.

If one knows of a device that can change 50Hz AC to any Hz AC then that would be great.. Or from a CVCC (DC) to variable Hz and Volt (AC) could also work.

[JW]

finally I think I figured out how to create a breaking force/ why I was not able to demonstrate that yet with shorted coils.

That is probably because the coils I shorted thus far while testing for that do not generate any magnetic field in the x axis where we need

This is called cogging

Now if only I could change the Hz going through my variac from 50 Hz to what ever it is I am aiming for. It might also turn out that low Hz PMA's are not really well suited for generating opposing/attracting fields to the magnets.

The diode bridge cares nothing about this.

"Are you planning not to use a rectifier bridge"? this the only thing im stuck

[JW]

Now if only I could change the Hz going through my variac from 50 Hz

A variac is a transformer device just using that in your circuit makes AC. Look around at the schematics for an invertor. Recently they have gotten away for this.

I am a TIG welder. in recent times these use solid-state instead of transformers.

 https://weldguru.com/inverter-vs-transformer-welders/   

[JW]

 Quote from link


Additionally, inverter welders can enhance the arc quality and provide valuable functions that were impossible with the old transformer welders.
just read the whole thing especially the inverter part

 https://weldguru.com/inverter-vs-transformer-welders

Inverter Welders
Inverter-based welders use modern technology to improve efficiency and reduce the machine’s weight drastically.

Additionally, inverter welders can enhance the arc quality and provide valuable functions that were impossible with the old transformer welders.

[JW]

If one knows of a device that can change 50Hz AC to any Hz AC then that would be great.. Or from a CVCC (DC) to variable Hz and Volt (AC) could also work.

grrrrr

[JW]

The induction motor can be functioned as a generator when the rotational speed of the rotor is made larger than the speed of the rotary field. In this regard, this study aims to modify the remains of 3-phase induction motor to be a permanent generator.

Yes, a three phase motor CAN be spun to operate as a generator, however, an induction motor used as such will still require a supply voltage, will Have to be spun faster than its normal operating speed and cannot provide reactive power, so would need a capacitor [bank].

will somebody please tell this guy yes you can over drive/generate using sprockets and chains. I don't know where he is going get the torque for this, the only way possible is with a diesel engine. Its all ready doing this, you need output toque from someplace like Niagara Falls hydro-drive   

[brandnewb]

I realize JW that I am a little struggling to confidently continue.

Anyway I plan on a Variable Frequency Drive in between the mains outlet and the variac to do a couple of things.

Measure which coil shape will result in the strongest x axis field.
Measure the heat dissipation characteristics at the intended frequency and voltage of a coil and in overload situations.

I will keep one posted of the results. And how I measure the actual breaking force at a know torque I still would realy like to know. I think the gravity torque setup is ready and waiting.

[brandnewb]

I am happy to report some progress.

rather than rotating the magnets over the coils at the intended frequency I did this.

Hooked up a coil to the oscope while in measure ampere mode. I am assuming it will internally short the coil to be able to do that.
Then I held the coil and waved it over the magnets at a much higher frequency than intended.

And lo and behold! I could feel resistance. yes!!!!!!!!!!!!!

I would still like to avoid having to introduce a planetary gear to increase the rpm of the PMA so I will continue first testing how I can increase the magnetic field of a coil while at a certain target VDC. If I use VAC for this then my tesla probe does not sample fast enough to measure any meaningful fields.
Strangely enough my phone and magnetometer app does but it is unwieldy and just not usable in this scenario because of the lack of a probe.

I do already think that fully encasing coils in iron powder resin is counter productive for the magnetic field (which might be higher sure than if without iron powder resin) to ever reach the magnets. But it could also still be that with having such strong magnets close by a fully encased coil the field will basically sucked out. I will do more tests.
At the very least fully encasing with iron powder resin is a cool way of demonstrating ridiculous heat dissipation abilities of a coil

So this means I will focus more on coil shapes that allow for an iron powder core and an iron powder top coating over all the coils as a whole, yet leaving the bottom of the coils exposed for the magnetic field to be not diverted away from the magnets.

Also this x axis field thought that I had turns out to be not the case. I can easily read similar fields on both the x and z axis. And grrr again I forgot to also measure the y axis ;(

[JW]

Okay "Pulse width modulation"

[brandnewb]

Please all tell me if you would trust results gathered like this or that you think it is not a good way of testing / quantifying things..

It would really make things easier to proceed as I still do not know how to proceed with the gravity torque setup as I had set it up by advice of someone here yet now I did somehow there is radio silence on whats next;(.

I think I have a way of reliably determining the AC induced magnetic field in the coils caused by the magnets while they rotate over them.

I can create tiny coils wound over a pen shape that act as tiny magnetic field sensors when hooked up to an oscope.
I can then read 4 of them at the same time. The voltage, how ever tiny, should be directly proportional to the magnetic field in the coil under test.
And in return the magnetic field in a coil should be directly proportional to the breaking force it can exert over the magnets.

Does this make sense? I sure hope so.

It will also enable far greater measurement of the effects of stacked coils as I fear that magnetic fields might start canceling out each other. And of course the loss of heat dissipation ability we have already seen that I still have not dealt with in a stacked configuration.

[MattM]

Wasn't the whole point of large radius radial design for high frequency?  Your frequency increases by pi as it gets bigger, so no gearing is required.  You need to figure out useful rpm's under a load and work from there.  You are probably aiming for 10-50 rpm's in all but the most extreme conditions.  Then you are probably braking.

[brandnewb]

Ahh I see brother where I failed to keep one informed about my thought process!

I think that when we use frequency as a guideline then the radial factor is negated.

Only the velocity at which a magnet traverses a coil is altered by the radius it is slung about as far as I understood it.

Sure I am aiming high and strange. This does not mean however that I need to abandon my core principles. I will go share those at my diary as I think I never did.

[brandnewb]

at first I was aiming for a large velocity for the magnets to traverse over the coils. And enough space to cramp in a modest amount of them. Hence forth this unwieldy 1.32m diam outer diam test bench.

It is not something one cares to install so it would make the humanitarian aspect completely void if I were hellbent on pushing forward with this radius. Let alone the engineering challenges.

But I am beginning to believe that the velocity factor is not a linear component in the whole. So I will explore around a bit until I hit this hard wall of physics demanding me to go back to an oversized radius.

[brandnewb]

The problem is, the magnet's radius is also a variable. You cant have the magnets too far apart, because when you connect all the coils together, the current is flowing through other coils which are not producing voltage.. so ideally you need 3 test coils, connected in Y, but shorted. Or perhaps better, rectify the test coils and short the rectifier.



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Yess Sir, good Point!.
Yet one can also not have the magnets too close together.

Is there an actual true and time trail tested design out there that is optimized in most ways one can think off?

Yet the context remains ultra low frequency.

Of course I might be mistaken but I am beginning to think I might be able to setup multiple experiments just to see what works or not.
You see I do not do so well with intimidating formulas.

[brandnewb]

Well Matt,

I can think of one way why your thought was founded.

You see when we increase radius we also increase surface area to place magnets in. And if we then use said space to double the amount of magnets then the frequency is doubled amongst other factors.

Wasn't the whole point of large radius radial design for high frequency?  Your frequency increases by pi as it gets bigger, so no gearing is required.  You need to figure out useful rpm's under a load and work from there.  You are probably aiming for 10-50 rpm's in all but the most extreme conditions.  Then you are probably braking.

[JW]

, so no gearing is required.

I brought up the sprockets and chain. that was me.

[brandnewb]

Please any and all. Please see if my plan of attack is sound or not.

What I meant earlier regarding the frequency staying the same but the velocity only changes might be conveyed like so.
I am working from a radia interval that is 3.75 degree between magnets. Below you can see such spacing at an 300mm inner radius of the magnets.

I would like to review with you guys a plan to determine which coil configuration (wire size and shape) in combination with which magnet configuration (traditional or repelling at various intervals of radia)



But also sometimes I try out to increase the density of the magnets by 100% and then one will end up with something like this.


 I am not sure how to compare apples to oranges.
Please let me explain.

I would like to see how to create the maximum magnetic field possible induced by magnets rotating over them.

So here is my plan of attack:
1) create a bunch of different test coils varying from 0.4mm diam wire size to 1mm diam. and also in shape.
Do make sure that the 0.4mm wire coils are at all times 4 x more winds than the 1mm one. As one can fit only 4 times that wire in the same space of a 1mm one.
2) run various magnet configurations over all variations of the coils at the intended frequency. for single density that would be around 3.8 Hz and for double density that would be double that.
3) record what voltage each coil can produce at said frequencies,
4) hook up an Variable Frequency Drive to the variac at the intended frequency and at the voltage level it would have produced while induced by the magnets spinning.
5) now measure the magnetic field on each coil making sure to also take into account the depth and area it encompasses ( larger is better for breaking ability)

I am really hoping for some debate on this. even if only to hear "sounds like a plan"