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Author Topic: Pulse coil and wheel travel  (Read 12491 times)

capthook

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Pulse coil and wheel travel
« on: September 04, 2009, 06:11:22 AM »
Why is the travel LESS with the pulse coil?

(See attached pics)

When the coil is energized in repulsion, it produces a noticeable and decent force.  Yet the wheel travels a shorter distance than without the coil.
My thought would be the coil core is still attracted to the magnet and thus retarding the wheels rotation.
But again, I can feel a sizable kick against the magnet from the coil.

Why wouldn't this kick add, rather than subtract, to the wheels rotation?

gyulasun

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Re: Pulse coil and wheel travel
« Reply #1 on: September 04, 2009, 11:24:13 AM »
Hi,

Have you tried the same test with the core removed from the coil?
Wheel travel should increase then...

The only answer I can give for the less travel is:  the core - magnet attraction force is not fully overcome by the push. Distance between the core - magnet and the current strenght : these seem to be the crucial factors.

Gyula

innovation_station

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Re: Pulse coil and wheel travel
« Reply #2 on: September 05, 2009, 05:31:21 AM »
PLOP A MAGNET ON THE BACK SIDE OF THE CORE IN BUCKING CONFIG ..  ;) :D

NOW IT WILL REPELL...

AND IF YOU SET THIS UP IN A MANY COIL CONFIG ...

IT DONT TAKE MUCH TO PUSH THE WHEEL ..

AND IF IT IS SET UP TO SELF POWER ... THEN ALL YOU NEED TO DO IS PUSH IT PAST 1 MAGNET TO START IT AS IT WILL OSCOLATE .. AND IF YOU COLLECTED THE OSCOLATION FROM THE ROTOR UPON START UP IT WILL INFACT CHARGE UP THE CAP TO SELF RUN ..

 ;)

OR GO AIR CORE AND COLLECT ONLY THE COLAPSE FROM EACH COIL ..

BESIDES AFTER THE RPM GETS TOO HIGH THE IRON WILL NOT RESPOND FAST ENOUGH FOR THE SPEED OF THE ROTOR ..

HENCE WHY MULLER MADE CRYSTALINE CORES...  :D

IST!

JUST BEING ME ..


capthook

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Re: Pulse coil and wheel travel
« Reply #3 on: September 06, 2009, 07:12:35 AM »
Thanks Gyula and IST for the replies.

Yes, it does appear the core/magnet attraction is not sufficiently negated.  It just seems the sizeable 'kick' would indicate a net gain.

I have tried countless combinations of airgap, core size, magnet size/strength, # of turns, wire size, voltage, amperage, drop heights and adding both attracting and repulsing backing magnets - all with poor results.

Some things I've considered: Thoughts, opinions, suggestions on these or anything else?

1. reducing core length by 50% from 3" to 1-1/2" as this may reduce the power input required?
2. presently, 3/4" of core is unwound at the far end to assist in coil mounting.  Using a different mounting method and eliminating this section of core might help?
3. different wire size, winding dimensions.  I'm of the notion that the current wind is good - but I'm open to suggestions.
4. exotic/annealed (expensive) core materials
5. different pulse coil construction.  See the attached 2 pics. This would make use of both ends of the pulse coil.  This seems the best option to proceed with next.  Thoughts/suggestions on this?

The problem has always been:
Design a device with decent torque/horsepower using a pulse coil with a large enough ferromagnetic core to attract a large permanent magnet from a modest distance and then release it without requiring a large input of like 10 amps.

Aaarrgh!!

gyulasun

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Re: Pulse coil and wheel travel
« Reply #4 on: September 06, 2009, 03:49:07 PM »
...
I have tried countless combinations of airgap, core size, magnet size/strength, # of turns, wire size, voltage, amperage, drop heights and adding both attracting and repulsing backing magnets - all with poor results.

Hi,

What do you mean by poor results? A COP between ,say, 0.2 to 0.6 or a COP between 0.6 to 0.9? 


Quote
Some things I've considered: Thoughts, opinions, suggestions on these or anything else?

1. reducing core length by 50% from 3" to 1-1/2" as this may reduce the power input required?
2. presently, 3/4" of core is unwound at the far end to assist in coil mounting.  Using a different mounting method and eliminating this section of core might help?
3. different wire size, winding dimensions.  I'm of the notion that the current wind is good - but I'm open to suggestions.
4. exotic/annealed (expensive) core materials
5. different pulse coil construction.  See the attached 2 pics. This would make use of both ends of the pulse coil.  This seems the best option to proceed with next.  Thoughts/suggestions on this?

Point 1:  I do not think the length reducement would bring significant improvement in your shown setup  (in certain other setups such a length may prove long but then you have to examine the possible affect of the other magnet pole getting closer to the setup if you reduce the length)

Point 2:  I guess the best place for the coil would be in the geometrical center of the core, shifting it towards either end may have effects on the strength of such electromagnet, tests are needed (I do not think this significant either)

Point 3:  What counts is Amper*turns and this involves many turns, however it involves long wire, hence ohmic losses, so the thicker wire you can fit into a given winding space the better, this is always a tradeoff

Point 4: No need for exotic core material, your enemy here is saturation and eddy current loss. Saturation can be 'controlled' by cross section area in case of lamination or ferrite cores, these two meet eddy losses too.

Point 5: YES!  Using both poles of BOTH the electromagnet(s) and the permanent magnet(s) is a 'free'  repel or attract force multiplier. Both your drawings are good in this respect, perhaps the first one is preferred because it needs one coil only.

Quote
The problem has always been:
Design a device with decent torque/horsepower using a pulse coil with a large enough ferromagnetic core to attract a large permanent magnet from a modest distance and then release it without requiring a large input of like 10 amps.

Aaarrgh!!

Yes, I agree but first I suggest building a setup which differs from the setup shown in your first post in that it has the electro and permanent magnets like you show in your second post, first drawing, I referred  to at Point 5.

AND what is important at this stage: as long as you cannot measure a COP of 0.8-0.9 at least (but I do not mean COP>1) you should improve the setup! You have to achieve it by all means, otherwise you have a poorer setup than a normal electric motor.

IN CASE you have managed to build your setup envisioned above , then and only then I think you can include so called 'improvements'... 
I mean using the parallel path principle for example (it is shown to multiply electromagnet force 3 times in practice (4 times in theory), using the same input power
or see this link: http://www.overunity.com/index.php?topic=4624.msg96814#msg96814
where member DMMPOWER uploaded a 'super electromagnet' drawing. I embedded a permanent magnet into your drawing ala DMMPOWER, see the uploaded picture below.

Also you can use Jack Hildebrand's magnetic valve too, you surely familiar with it.

I do not claim you will surely get COP>1 with my suggestions (I have not tried them) but the possibility is open for it. Especially in case you really achive a COP of 0.8-0.9 first without the permanent magnets embedded, this is one important rule to observe. (At this stage you can include the electric energy captured from the flyback pulse at switching of the coil, the point is to get a decent efficiency like a conventional electric motor has, and I think of the 80-90% efficiency range;  I know there are conventional motors with much poorer efficiency.)

Use a rotor disk with a 20cm OD at least (or higher) and mount on it (vertically) at least 10 yokes with 2 magnets on their ends each. For the yokes you could use AM radio ferrite rods or a pile of laminations.  Regarding the stator yokes, it is more problematic because normally it is difficult to make a hole i.e. an empty space into a core for inserting later a permanent magnet. Probably this is the most problematic part in my suggestion.  Will ponder on it too. Wonder how DMMPOWER solved this? This same problem was to face Jack Hildebrand in his valve too.

rgds, Gyula

EDIT: see this patent too: http://v3.espacenet.com/publicationDetails/biblio?CC=US&NR=2002175580A1&KC=B2&FT=D&date=20030211&DB=&locale=

capthook

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Re: Pulse coil and wheel travel
« Reply #5 on: September 08, 2009, 09:35:02 AM »
Gyula -
Thanks for the excellent thoughts and comments!

For some reference, the idea is similar to patent #: 5,258,697
( http://www.google.com/advanced_patent_search and input the patent number in the search parameter)

The magnet is attracted to the EM core.  As the magnet centers over the core, the EM is pulsed for a very short duration with just enough current to negate the attraction and let the PM spin on past.

There are a number of differences to this patent, but it's the same general idea.

Also, the output shaft is connected to a generator, specifically a dual-rotor axial flux (air coils/low drag).
The output is collected on a capacitor and then used as input.
Final design I suppose should use Lio-Ion rechargeable batteries as they offer ~99% efficiency. (vs. 50% capacitor, ~85% lead acid depending on SOC)

As to COP, I'm hesitant to make specific claims at this point, but will share some figures in the near future.

I've seen your mention of the DMMPOWER 'super electromagnet' in the past - an interesting idea.  A possible construction method might be using steel bars to surround a PM.  Like 4 pieces of 1/2" 1018 for the top/bottom/sides and then wrapping a coil around that.
A backing magnet might offer the same principal?

An attraction magnet placed at the far end of the core/coil can offer an advantage.
For example, when attracting a PM over a distance and pulsing with 9V:
1) core/coil:                                2" attraction distance / 1" airgap needed to negate attraction
2) core/coil with backing attraction magnet: 4" attraction distance / 2" airgap needed to negate attraction
So it takes 1" of added airgap to gain 2" of attraction distance ~ 2:1
With a repulsion backing magnet, the EM repulsion strength is increased, but the attraction distance is reduced to almost nothing as you must get close enough to the core to overcome the repulsion field provided by the PM.

I'm wondering whether the current coil, with an attraction backing magnet, would outperform the other 2 coil design that use both ends of the coil.
Hmmm, I guess one might use the horizontal/2 end coil and then place attracting magnets to the backsides... (see attached pic)

edit: or even the 'horseshoe' magnet like the 2nd pic
Which of the 3 coil designs might be best?
Hmmm.... then again, the backing magnets on the 2 coils pictured wouldn't probably work...
« Last Edit: September 08, 2009, 10:08:53 AM by capthook »

capthook

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Re: Pulse coil and wheel travel
« Reply #6 on: September 08, 2009, 12:27:54 PM »
Dual-rotor axial flux generator build pics and info

1) stator mold out of 1/2" plywood.  Bottom piece square, mold/upper piece cutout to diameter of stator, center piece cut to form center hole.  Pieces sealed with caulk and then waxed to ease stator removal.  Bolts to tighten lid.

2) finished stator.  Wired 3-phase star.  Each Coil: 3/4"ID, 2"OD, 3/8"depth, 24 AWG, 500 turns, 4.7 ohms, 14.10 ohms per phase.

3) left rotor.  Rotors normally made with solid steel to complete magnetic circuit, this is cut from 1"x 12" pine with (3) circles of 16 gauge steel then affixed to reduce weight by 65%. (steel cut by hand with a jigsaw with steel blades)

4) right rotor.  Duct tape to protect magnets and extra hold as they are usually poured in epoxy and I wanted the ability to change/modify the magnets.

5) Assembled axial flux.  This picture has additional pulleys added (and since removed), 1:4 ratio.  Increasing RPM's massively increases output, at the cost - of course - of increased Lenz drag.

Specs:
Magnets: 3/4"D x 1/2"H N42 Neos
airgap between each rotor and stator: 1/8"
Output @ 60 RPM: 12 watts : 20 volts @ 0.6 amps
Output @ 240 RPM: 190 watts (4x RPMs = 16x output, thus the pulley idea)

capthook

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Re: Pulse coil and wheel travel
« Reply #7 on: September 10, 2009, 08:27:51 PM »
Thanks for the reference to the Flynn PPMT.  I've re-read and studied the patent and various discussions and has given me some ideas.
While some argue Flynns PPMT is similar to the 'astroboots' and thus the patent is not novel, the volume of details and unique methods is beyond a doubt novel and the information presented is of great value and interest.

Referring to Patent 6,342,746 : Figures 16B & 16C also 47 & 48
Please refer to numbered attached pictures.

(1) Using polarized armatures.  Graph line 391 shows current required (point 393) for flux to =0 on lower armature.
(1 amp @ (x?) volts = (y?)  watts?)

(2) 2 permanent magnets with non-polarized armatures.

(3) Combining 1 & 2

The goal would be to lift 5 lbs. from a distance of 1/2" and then fully release the load (flux = 0) with a small coil input using method (3).

A primary question is magnet strength.
Ceramic magnets are normally recommended to prevent core saturation.
However, Jan Vink's replication ( http://peswiki.com/index.php/Directory:FPPP:Replication:Jan_Vink ) uses N42 neos and 15 watts.  He reports N35 neos as using .88 watts (although magnet dimensions aren't given. I would suppose they are a bit smaller given the results??)
Larger/stronger magnets will provide greater/further lift.

Using 2 permanent magnets in the device adds additional 'free' flux vs. the 1 of picture (1).
Might additional magnets be of benefit? A row of 4 or 6 etc?  Or stacking them 2 or 3 deep?

Will the additional power required to negate the polarized armature be overall less efficient than just using a non-polarized armature?

What advice, methods, thoughts might result in achieving the goal?
What power input might be required?


gyulasun

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Re: Pulse coil and wheel travel
« Reply #8 on: September 11, 2009, 12:00:30 PM »
Hi,

One more measurement report on ppt, if you are not yet aware of: http://www.flynnresearch.net/young%20scientist/Josh%20Jones/josh.htm  see Josh's research paper http://www.flynnresearch.net/young%20scientist/Josh%20Jones/PPMT%20Research%20Paper.pdf
From Page 3 of Josh' paper:

" The armature pull-off tests that were performed with no magnets, the 1,200 turn coils on and powered, and the 0.070 shim produced an average of 3.72 newtons of force. The configuration with the magnets, no coils, and the 0.070 shim produced an average of 8.75 newtons of force. Therefore one would think that by adding the two configurations together that the force would equal 3.72 newtons plus 8.75 newtons. But with the two configurations together the pull-off force increased considerably to an average of 22.82 newtons. This does not violate the laws of conservation because there are a total of 3 flux producing sources in the fixture – two magnet stacks and a solenoid. All must be considered when looking at the effect. The apparatus uniquely concentrates the sources in a single armature. "

Re on your question on magnet strength,  I believe it all depends on two things:  the core saturation data (ferrite -> lamination/hypersil -> metglas) and core cross section area.  You have to consider saturation for the COMBINED flux where-ever it appears in the magnetic  path (it is mainly in the end pieces or armatures).

Have little time now, will be travelling for a week or so.

rgds, Gyula