Circuit setups for pulse motors

[hoptoad]

I'm going through various common steel tubes to see which ones will work the best but as usual it will be trial and error. In the link, you said they work better as pickup coils and I do believe it but I'm more focussed on the drive aspect.

Can you suggest the optimum AWG wire size for drive coils if I'm using 2 X 1 X 1/2 N42 Neos?

Currently using 20AWG and have a single winding resistance of +/- 6 ohms and can adjust my input to approximately .1 amp.

@Casman

To see any real difference in operation with hollow cores, you need to compare apples with apples (hollow). By basing the outer dimensions of your hollow core, on the dimensions of a solid or laminated or air core that you're already using, a reasonable comparison of the differing properties of each core can be made.

Assuming your supply is 12 Volts, then "+/- 6 ohms" (is that six ohms)  DC coils wound onto hollow cores of the same diameter and length of a solid core, should yield very good comparative results.

Hollow cores will have less inductive reactance than a solid core due to the lesser amount of core material, but a greater current consumption associated with less reactance should be offset by an increase in the rotor speed due to lower magnetic drag . This raises frequency and causes reactance to rise again. Its a game that pulse motors play 

To increase impedance of a coil (on any core), you can (a).Wind more turns on your coil, (b) increase the diameter of the core (c) increase the length of your core,  or  (d) any combination of all three methods.

Make a coil based on what you already have, then learn and proceed from there. Then you can decide yourself how to redesign your coil to best utilize the positive benefits of a hollow core, and how best to solve the inadequacies of low impedance cores.

I am glad you are going to experiment with hollow cores. I hope you discover something that I haven't.
I don't want to steer you too much in any direction with hollow cores,I  would rather let you find out whatever there is to find out by experimenting yourself, and reveal your results to all of us here, because an objective, untainted "fresh" opinion about them is welcome and needed....KneeDeep 

Cheers from the Toad Who Hops   

[Ren]

Baker I struggled to come to grips at first with controlling amp draw. Its not as simple as plugging a hole so less comes out. Then again maybe it is. You will need to build your circuit and test various resistances and configurations WITHIN the circuit to vary current draw. You simply cant place a choke on one end.

Well, you can, sort of. I see the coil as being similar to a choke. The thinner the wire and the more turns creates greater resistance (travel path) for the energy to flow. The pulsing aspect will also do this too as current is being switched on and off.

This is why I recommend a Bedini build for your first. Its so simple and schematics are everywhere. You will get results if you follow the instructions, and you will have something that works.

You will also have a better understanding of the components and general assembly of your motor which will allow you to move forward onto better things.

[Artic_Knight]

im very confused about back emf and cores now. from what i have read in this forum the best core is an air core, from what i read about the adams motor the best core is an iron core.

the Adams pulse motor uses a perm magnet and uses the pulse of electricity from batteries to positively attract the magnet, then when the magnet is within range, the current stops the magnetic field that was in the iron colapses and creates a reverse current that pushes away, so now for the same pulse of an air core your getting both the pull and push for same energy. a much better deal if it works.

however this group does not agree? has anyone tried this particular method?

and now there is 2 different descriptions of back emf, if they are the same please let me know, however now we have a reversal of the magnetic feild with or without the perm magnet to produce it. and it appears this reversal counters the attraction the magnet has on the iron and with enough force even repells!

does anyone have a good idea about these forces? if theres a website that is good too.

[Artic_Knight]

ok i found some websites but im still confused at the moment, maybe i can figure it out later.

the motor layout i have seen on one website uses iron core that is positively magnetized and the magnet is attracted to it, then the current stops and the magnet is pushed away from the magnetic field collapsing and reversing?  but your talking about taking this back emf in the form of electricity and reusing it?

[Ren]

Artic I too get a little confused with all the "emf" terminology. Hoptoads page explains it well, but it still isnt quite clear in my head yet.



I see there being two ways to operate an "Adams style monopole motor" You can wire your coil to fire in attraction or repulsion. But if your clever you can benefit from both styles. My monopole fires just after dead center, repelling the magnet closest, but at the same time attracting the scalar south from the next magnet. So it kind of harnesses both attraction and repulsion. A break down of the SG bifilar monopole would be as such:

coil (off) with no magnet in the vicinity.
Magnet approaches coil (off) attracted to the iron core inducing voltage through both wires.
Trigger winding in turn uses the small amount of voltage induced to "fire" the power winding, completing a circuit momentarily around the iron core.
Coil(now on) magnetizes core and becomes an electromagnet of same polarity to rotor magnets.
Rotor magnet is push/pulled away and induced voltage dissipates from coil, shutting off circuit and collapsing magnetic field.
Collapse is collected and cycle repeats itself.

This isnt how all styles of pulse motors work but it is a basis for basic models. It can work slightly different in that the pulse attracts the rotor and switches off at the precise moment as to prevent the rotor hanging up in the magnetic field.

I like to see it like this. You can collect the collapse of the coil and other associated energies with the appropriate circuitry, of which most is covered at the totally amped page. How you chose to store and reuse that energy is up to you. There is plenty of different ways to trigger your circuits to fire and plenty of different ways to collect that which is normally wasted.