Pulse motor build off time.

[Farmhand]

Gyula, I already used two coils in series but in a charging circuit configuration, the current through the charging coil lags the main drive coil, I also used it in a push pull fashion by reversing the polarity of the charging coil so that the lagging current produced an opposite polarity which pulled the magnet just after the main drive coil pushed it.

I should have used invert on the scope.

Charging coil aiding to rotor drive while increasing the voltage switched through the main drive coil.
Skip to 7:20 in the video to see the effect of removing the charging coil so it's just working as a resonant charging circuit only, then the effect of using the charging coil to aid the rotor torque.
https://www.youtube.com/watch?v=w1_KlgJ09Bs

Timing effects.
https://www.youtube.com/watch?v=0whkutQ7mNQ

The charging coil discharges it's flyback into the capacitor that discharges through the main drive coil and the flyback from the main drive coil can be returned to the supply capacitor before the charging coil.

As can be seen at the start of this video the motor can run with a quite small input at a good rpm and smooth from 12 volts but I had a boost converter at the input so I used it. 
https://www.youtube.com/watch?v=Yukaj0QQzN0
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What exactly are the Judging criteria for the Build off ?

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[Centraflow]

Thanks Gyula

Yep I think you about hit it on the head there, he certainly builds a nice machine

regards

Mike

[gyula]

What exactly are the Judging criteria for the Build off ?

..

Hi Farmhand,

I do not know the exact judging details and here is the link to learn about it:
http://open-source-energy.org/?topic=2159.msg29188   

Thanks for showing your setups, they are a bit different from 'Mister Caribbean Roots' setup discussed here.  When I have some more time, will try to go through your videos.

Gyula

[Tommey Reed]

Hi All,

Just a few more days to complete the 2014 pulse motor build off.

This is my update on my radial pulse engine test run.

https://www.youtube.com/watch?v=zWxWJrjjRVY


This is my basic specs.

Spec:
Radial Pulse Engine/motor/generator
Input 12v@3a max (motor input), stall load 56w
Input 9v@ 40ma (micro controllers)
8 coils 24 gauge at 100 ft each (2.567ohms)
PWM speed control
2 micro controllers for lcd and motor control (arduino base atmega 328 16mhz 32k)
ECM reading/controls
Rotational 5 degree steps (72 steps per complete rotation)
Control firing power stoke on each piston coil 0deg(TDC) to 180deg(BDC)
8 led piston firing lights
RPM reading (0- 3600)
Output:
BEMF collector from 8 coils

Tom

Tom

[Verpies]

This might help some experimenters who are pulsing inductors (e.g. motor windings) and later are trying to recover energy from them.

When a rectangular pulse transitioning abruptly from 0 to some voltage V is applied to a resistor in series with an inductor (e.g. a coil) by closing the switch in the diagram below, then the following sequence of events happens:

• 1) At the beginning (point A) no energy and no current is flowing (the switch is open).
• 2) Shortly after the rising edge of the stimulating pulse (after the switch closes), the current increases linearly
• 3) Some of the energy of the pulse is converted into the magnetic field in the inductor and some energy is dissipated in the resistance as heat. At this point the energy flows into the inductor faster than it is dissipated by the resistor.
• 4) After the time equal to 0.69 Tau (point B) the energy flow (a.k.a. power) into the inductor reaches its peak and starts decreasing afterwards, eventually reaching zero power and magnetic energy equal to ½*L*(V/R)², at Tau >> 5
• 5) However the current through the resistor keeps increasing non-linearly but monotonically and asymptotically up to the V/R limit and the energy flow (a.k.a power), dissipated as heat in the resistor, increases similarly up to the V²/R limit.
• 6) After time equal to 1.15 Tau (point C), the magnetic energy accumulated in the inductor reaches the break even point with the total energy dissipated as heat in the resistor up to that point in time. Continuing beyond point C guarantees that more energy is dissipated as heat in the resistor than stored as the magnetic field of the inductor.
• 7) After a very long time the current reaches the V/R limit and the magnetic energy stored in the inductor reaches ½*L*(V/R)² limit but the energy dissipated in the resistor increases ad infinitum at the rate (a.k.a. power) equal to V²/R.

For transformers, putting a load on the secondary winding (e.g. shorting it) has the same effect as decreasing the inductance of the primary winding (L). As a result of this, the Tau decreases and the current in the primary rises faster with time.

If the voltage V of the power supply is suddenly decreased to zero (while the switch is still closed), the sequence above reverses, the electric current in this circuit decays asymptotically back to zero but it does not reverse direction and the energy keeps being dissipated as heat in the resistance as long as any current is flowing (i.e. the entropy does not reverse either).


THE POINT:
If a constant and linear inductor is charged and later discharged at the same rate, then from efficiency point of view, it makes no sense to charge it longer than 0.5757 Tau (½ of the time C, see pt.6), because if you do, then the energy dissipated in the resistance will be higher than the energy recovered from the inductor during its discharge. 
For realistic good recovery efficiency from the above inductor, the charging time should be less than ⅛Tau.



LEGEND:
Tau = L/R (a time constant)
V = The high level voltage of the stimulating rectangular pulse.
E_TOT = Total energy delivered by the supply to the series RL circuit.
E_L = Energy stored in the inductor as magnetic field
E_R = Energy dissipated in any resistance as heat
P_L = Instantaneous Power (energy flow) flowing into the inductor
P_R = Instantaneous Power (energy flow) dissipation in the resistance
i_L = The current flowing through the inductor (and resistor)
       ( I can post the relevant time-domain equations on request )

[Verpies]

In pulse motors, which use energized coils to attract a soft ferromagnetic element of the rotor^*, there is an additional significant phenomenon that needs to be accounted for.

For simplicity, let's consider an empty^* air-coil (solenoid) possessing some inductance L_MIN.
1) This empty air-coil is first energized up to some current (i_MAX) from some external power supply.
2) For simplicity of analysis, the charging of the coil's current is stopped at i_MAX, long before the point C on the current waveform is reached and the coil is shorted to preserve the current in it.
3) A movable soft ferromagnetic element (nonconductive) appears a distance away from the coil.
4) Now the coil attracts the movable ferro/ferrimagnetic element (e.g.: a ferrite slug) towards itself, because current keeps circulating in the shorted coil and magnetic field B-gradient is generated by it.
5) As the ferromagnetic element approaches the coil, its ferromagnetic domains become increasingly ordered.
6) As the ferromagnetic element approaches, the coil transitions from a coreless coil to a cored coil and the inductance of the coil increases. In response to that, the current flowing through the coil's winding decreases in order to maintain the flux, which threads the coil, constant.
7) When the ferromagnetic element becomes attracted all the way into the coil, its inductance reaches maximum (L_MAX) and the current flowing in it, reaches the minimum (i_MIN).  This would happen even in a superconducting coil devoid of resistance.


8) The coil is opened and all the energy circulating in it (½L_MAX*i_MIN²) is quickly discharged into a capacitor.
9) The order of the domains acquired in pt.5 is lost.
10) The movable ferromagnetic element continues to move away from the coil by inertia and unimpeded by attraction from the deenergized coil.



DISCUSSION
The decrease of current described in pt.6 will be manifested on the scope as flattening of the pulses' tops. This flattening can be confused with reaching the V/R limit of the winding.  To distinguish them, a dry run should be made first with the movable ferromagnetic element absent.  The results of the dry run can be later subtracted out.

Furthermore, when the coil is discharged into capacitor in pt.8, it should be noted that the smaller this capacitor is, the faster the energy stored in the coil will be transferred into that cap.  The downside of a small capacitor is that the voltage which it becomes charged to, is large.
In other words, the smaller the capacitor - the faster the coil's discharge but the higher the capacitor's final voltage because ½L_MAX*i_MIN² = ½C*V², and this transforms to V = i_MIN*SQRT(L_MAX / C)
Also note, that this capacitor and the winding form an LCR circuit that wants to oscillate at the frequency equal to 1/(2π*SQRT(C*L_MAX)). 
If the goal is to transfer all of the energy from the coil to the capacitor, then this oscillation should be interrupted after ¼ of the cycle, when the current in the coil is zero and the voltage in the capacitor is at its maximum. The energy stored in this capacitor can be transferred back into the power supply or used for supplementary supply to the coil in the next motor cycle.

Once all of the coil's energy is transferred into the capacitor, the resistance of the winding and the remaining circuit, cannot keep wasting it as heat and you can relax while preparing for the next cycle of your motor.

* Adams' motors do not do that.

[Verpies]

For the average experimenter who does wish to maximize energy return from the inductor, what would be a practical oscilloscope display showing optimal pulse width?

A triangular or sawtooth waveform of current.
Any flattening of the pulses' tops (such as in a rectangular waveform) or decreasing steepness of the current waveform is an indication that the current is approaching the V/R limit of the winding and point C has been left behind a long time ago (see the yellow dashed line on the graph).

[JimBoot]

Wow thanks  verpies. That should go into the documentation section as a permanent resource.

[Tommey Reed]

Hi All,

Just about done, boy this is a pulse engine/motor.


Spec:
Radial Pulse Engine/motor/generator
Input 12v@3a max (motor input), stall load 56w
Input 9v (micro controller)
8 coils 24 gauge at 100 ft each (2.567ohms)
PWM speed control
1 micro controller arduino 2560 mega
ECM reading/controls
Rotational 5 degree steps (72 steps per complete rotation)
Control firing power stoke on each piston coil 0deg(TDC) to 180deg(BDC)
8 led piston firing lights
RPM reading (0- 3600)
Output:
BEMF collector from 8 coils

[Verpies]

Just about done, boy this is a pulse engine/motor.

Are your electromagnets hollow air cored ones or sth else?
Are your pistons made out of a soft ferromagnetic materials or hard ones (magnets).
How do you prevent these pistons from hitting the electromagnets?

[Tommey Reed]

Hi verpies,

This is a air core set up, but could also be ferromagnetic fields.
The pistons are neo-magnets...

The pistons move through the hollow core and is energized when the timing is set with a 360 deg disk incoder.

Tom

[Verpies]

OK, so you have hollow solenoidal electromagnets with hard ferromagnetic pistons (permanent magnets).
...but how do you prevent these pistons from hitting or rubbing these electromagnets?

[Tommey Reed]

HI Verpies,

I really don't know what you mean by how I'm not not hitting the electromagnets?

The magnet go through the tube where the outer field (electromagnet) is located.

Tom

[Verpies]

I really don't know what you mean by how I'm not not hitting the electromagnets?
The magnet go through the tube where the outer field (electromagnet) is located.

OK, that's what I wanted to know.
A tube is guiding the piston to go through the coil and the piston rubs the inside of this tube.
This tube acts as a linear bearing.

What material is this tube composed of?

[Tommey Reed]

Hi Verpies,

This was a test run I did a few days ago, but I needed to add a more powerful micro controller.

https://www.youtube.com/watch?v=zWxWJrjjRVY&list=UUVuWbGDWWuR8Wszuv4zmLgA

Tom

[Tommey Reed]

Hi all,

This is my understanding of how a real pulse motor should work

https://www.youtube.com/watch?v=ol60QtAnxf0

Tom

[NerzhDishual]

Very advanced impressive device!
I would give you the first price.

[Tommey Reed]

Thanks  NerzhDishual,

Now just wait when I show it running....

Tom

[Tommey Reed]

Hi All,

This is my radial pulse motor generator entry.
3 minutes is short time to talk about this motor, but they are the rules.

https://www.youtube.com/watch?v=2bWRBHvb6mM

Spec:
Radial Pulse Engine/motor/generator
Input 12v@3a max (motor input), stall load 56w
Input 9v@ 40ma (micro controllers)
8 coils 24 gauge at 100 ft each (2.567ohms)
PWM speed controller
1 Arduino 2560 mega
ECM reading/controls
Rotational 5 degree steps (72 steps per complete rotation)
Control firing power stoke on each piston coil 0deg(TDC) to 180deg(BDC)
8 led piston firing lights
RPM reading (0- 3600)
Output:
BEMF collector from 8 coils


Good luck to everyone, some real good builds out there :cheerleader:
TLR

[Tommey Reed]

Hi All,

This is a complete build of this radial pulse engine from the start x8 the speed, no I'm that fast of a builder.

https://www.youtube.com/watch?v=U36pLafn_M8

Tom

[Matt Watts]

Okay gang, this is what we have for the final entries:

http://rwgresearch.com/events/pulse-motor-build-off-2014/

Enjoy the show.

And do try to learn something.  There is a lot of talent in those videos--something for everyone.


PhysicsProf, how about a rundown of what you find the most fascinating...   

[JimBoot]

Thanks for posting that link Matt they were inspirational!

[Matt Watts]

Thanks for posting that link Matt they were inspirational!

Yes they are.  I wish we had a clear self-runner entry to study though.  Maybe next year if we don't figure something out sooner.

[Tommey Reed]

Hi All,

I am in Florida today, the weather is 75deg.

If I win or one of the winner I will be able to call in the smart scarecrow show Saturday show that starts a 7pm.

Say warm....

[Tommey Reed]

Hello All,

These are the winners of the 2014 pulse motor build off.

https://www.youtube.com/watch?v=VOcXsR0lxxg

Tom