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Author Topic: Pulse motor build off time.  (Read 115525 times)

TinselKoala

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Re: Pulse motor build off time.
« Reply #150 on: December 06, 2014, 10:19:42 AM »
Sounds like a good plan!

Also might make a good bass lure: propeller from water drag making vibration, driving piezo, lighting LED, no battery required!

ALVARO_CS

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Re: Pulse motor build off time.
« Reply #151 on: December 06, 2014, 07:00:09 PM »
Hi Hoptoad
Have you re-loaded anywhere that Adams motor page you had long ago ?
wish to have another look at it (I learned a lot from it,thanks)
cheers
Alvaro

gyulasun

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Re: Pulse motor build off time.
« Reply #152 on: December 06, 2014, 07:47:31 PM »

ALVARO_CS

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Re: Pulse motor build off time.
« Reply #153 on: December 07, 2014, 12:24:55 AM »
many thanks Gyula ;)

TommeyLeeReed

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Re: Pulse motor build off time.
« Reply #154 on: December 10, 2014, 04:57:43 AM »

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

Tom

MarkE

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Re: Pulse motor build off time.
« Reply #155 on: December 10, 2014, 05:05:18 AM »
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

Tom
It looks great.

TommeyLeeReed

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Re: Pulse motor build off time.
« Reply #156 on: December 10, 2014, 05:25:36 AM »
Hi Mark,

I needed more computer power like arduino mega, ran out of pin ports to do more controls.

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

MarkE

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Re: Pulse motor build off time.
« Reply #157 on: December 10, 2014, 05:37:50 AM »
I hate it when  I come up short on pins.  One way around that if the timing isn't critical is to use an I2C I/O expander.  Otherwise just a chip with more I/O will do. 

I think your build shows a lot of creativity and you made it work the way you wanted, so my hat is off to you.  Good luck.

tinman

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Re: Pulse motor build off time.
« Reply #158 on: December 13, 2014, 01:59:17 AM »
PMBO 2014 - Second Entry,
This is my second entry just in case the first one gets disqualified since i'm being lazy and running the DC motor with a PWM...lol...^^
At the 2.29 min mark it sound like i said "max of 200ma" but i said "max to 100ma" but since i talk funny it sounded like 200ma...lol
At the end of video are 3 pictures...;-)
Good luck everyone and remember to have fun...having fun and learning at the same time is of much more importance than to win...^^

https://www.youtube.com/watch?v=autinZjf_l8&list=UUNk6nZuUrTLRnp__hAgAqjw&index=1
Once again TJ,another nice build.
Hope you post it on IAEC ;)

MarkE

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Re: Pulse motor build off time.
« Reply #159 on: December 13, 2014, 03:11:20 AM »
PMBO 2014 - Second Entry,
This is my second entry just in case the first one gets disqualified since i'm being lazy and running the DC motor with a PWM...lol...^^
At the 2.29 min mark it sound like i said "max of 200ma" but i said "max to 100ma" but since i talk funny it sounded like 200ma...lol
At the end of video are 3 pictures...;-)
Good luck everyone and remember to have fun...having fun and learning at the same time is of much more importance than to win...^^

https://www.youtube.com/watch?v=autinZjf_l8&list=UUNk6nZuUrTLRnp__hAgAqjw&index=1
The machining is so good that until the end it is hard to see that it is rotating.

tinman

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Re: Pulse motor build off time.
« Reply #160 on: December 13, 2014, 03:55:34 AM »
Hi there bro and thanks,
How you been lately, do you have any time at hand to build something since you have absurd working week hours... :'(
I haven't post it on IAEC since i don't have any login info from there anymore... :o
Have a great weekend mate and before you know you're off to that nice Island with your lady...not long more to go... 8)
Cheers
Today is my first day home in 5 days. Did an 82 hour week this week,and feeling ::) lol. But just went down to the hardware shop,and bought some supplies to start my build. The first idea is canned,as the stator core is no good for the project. So now im going to build a large electric pulse hit and miss motor--all MDF to lol.
Anyway-im off to the work shop-time is short.

gyulasun

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Re: Pulse motor build off time.
« Reply #161 on: December 13, 2014, 12:13:28 PM »
PMBO 2014 - Second Entry,
This is my second entry just in case the first one gets disqualified since i'm being lazy and running the DC motor with a PWM...lol...^^
At the 2.29 min mark it sound like i said "max of 200ma" but i said "max to 100ma" but since i talk funny it sounded like 200ma...lol
At the end of video are 3 pictures...;-)
Good luck everyone and remember to have fun...having fun and learning at the same time is of much more importance than to win...^^

https://www.youtube.com/watch?v=autinZjf_l8&list=UUNk6nZuUrTLRnp__hAgAqjw&index=1

Hi Mister Caribbean Roots,

Very nice and robust setup! Would you mind answering some questions? ( If you do not wish to answer, I understand   8) )

1) I edited a snapshot taken from your video to symbolize the position of a possible ferromagnetic core inside your generator coils: do you use 12 such short cores for the 12 coils?

2) Have you estimated your output power? whether it is higher than approximately 3 Watts?

3) Did you find in your practice that the tangential position for the output coils (as you did) with respect to the rotor gives less drag than the (usual) radial position?

Thanks,
Gyula

verpies

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Re: Pulse motor build off time.
« Reply #162 on: December 13, 2014, 02:40:25 PM »
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.


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.
ETOT = Total energy delivered by the supply to the series RL circuit.
EL = Energy stored in the inductor as magnetic field
ER = Energy dissipated in the resistance as heat
PL = Instantaneous Power (energy flow) flowing into the inductor
PR = Instantaneous Power (energy flow) dissipation in the resistance
iL = The current flowing through the inductor (and resistor)
       ( I can post the relevant time-domain equations on request )

verpies

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Re: Pulse motor build off time.
« Reply #163 on: December 13, 2014, 02:41:55 PM »
In pulse motors 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 LMIN.
1) This empty air coil is first energized with current (iMAX) from some power supply.
2) For simplicity of analysis, the charging of the coil's current is stopped at iMAX, long before the point C on the current waveform is reached and the coil is shorted and a movable soft ferromagnetic element (nonconductive) is introduced a distance away from the coil.
3) Now the coil attracts the movable ferromagnetic element towards itself, because current keeps circulating in the coil and magnetic field B-gradient is generated by it.
4) As the ferromagnetic element approaches, the inductance of the coil increases and in response to that, the current flowing through its winding decreases.
5) When the ferromagnetic element becomes attracted all the way inside the coil, its inductance reaches maximum (LMAX) and it current falls to minimum (iMIN).  This would happen even in a superconducting coil devoid of resistance.
6) The coil is opened and all the energy circulating in it (½LMAX*iMIN2) is quickly discharged into a capacitor.
7) 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.4 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.6, it should be noted that the smaller this capacitor is the faster the energy in the coil will be discharged into it.  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 ½LMAX*iMIN2 = ½C*V2, and this transforms to V = iMIN*SQRT(LMAX / 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*LMAX)). 
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 to energize 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.

TommeyLeeReed

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Re: Pulse motor build off time.
« Reply #164 on: December 13, 2014, 03:56:32 PM »


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