Shorting the gen coil with PWM? .. and other things.

[Faraday88]

for this application mosfet's work better

I remember, Aviso Ismeal got special High-Power MOSFETS/IGBT designed for his Coil shorting experiments...

[RS_]

i think in theory that works too.... your paying for a small AC current on a low voltage primary to make the voltage peak on a high voltage secondary, that you only short on the peak, so no current flows during the ramp up to peak, and the fall down from peak, and you harvest the ringing into a cap......

[Bradley Malone]

Has anyone tried the coil shorting on a transformer. I am just thinking if there is no current used until the peak then short it would it do the same thing as is not use current to set up the field then short to create a back pulse that will help the current in the primary on the downside of the peak. From my understanding if you hook up a transformer with open secondary then the only current used is because of the resistance of the coil (wich is not much) therefore it sounds like it may perform the same taking very littole current to set up the voltage then connect and use it???

[RS_]

use 50k to 100K pots, with a 1K resistor in series with each. Start with a 0.1uF cap, and try 1.0uF, 0.01uF and 0.001uF to see what happens on your scope. On the output, put a 470ohm resistor from the pos rail to the not flat side of a LED lead, then hook the flat side lead of the led to the output pin #3, then another led's non flat side lead to pin #3, then the flat side lead to a 470ohm resistor, and that resistor to the gnd rail.... the led's will flash on and off alternately at the speed and duty cycle that the R1, R2 and C values are set to........ some times it helps to have a 5K pot in series with each of the other pots, for fine tuning.....

Carlos, the 13y old local boy, just build this same 555 timer circuit on a bread board a few days ago, and when he watched the LED's and watched it on a scope to see what it was doing as he changed things, he was grinning ear to ear.......


ps... you can also use a 50K to100K pot, with a 1K resistor in series with it, in place of R1

[AlvaroHN]

THANK YOU!!! that was what I was looking for, a simple pwm adjustable circuit using 555. Question: what values of pots resistences and cap should I use? since the diagrams don't have values, sorry to be suck a pain in the a..

[RS_]

for this application mosfet's work better

[RS_]

the TI LM555 micro power timer..... very nice 555 circuit with a very low power consumption compaired to the older models or other brands of LM555 timers, good for many kinds of projects..............

http://www.ti.com/lit/ds/symlink/lm555.pdf

Use circuit 4 "independent variable timing for both portions of the output cycle" ie: a fully adjustable PWM

http://home.cogeco.ca/~rpaisley4/LM555.html

[AlvaroHN]

Ok RS I will see what I do, ur circuit scares me a little (to many components), why mosfets and no transistors? I thought that transistors switched on/off harder.

[RS_]

because their is not much voltage built up in the coil from zero crossing to about 3/4 of the way up to the peak, and if any current flows during this time, it will create drag on the rotor/prime mover, wait till just after TDC, and there is no drag

if you build a coil shorting circuit like i show, and use your reed switch to trigger it at the peak, it is the same as using a hall sw to trigger that coil shorting circuit.......

use 2 reed switches setup to trigger on pos and neg peaks

and if you want to test shorting all through the wave form, than 1 555 timer circuit can trigger my coil shorting circuit as many times during the full wave form as you adjust it to......

[AlvaroHN]

RS_ I want to do the same but simpler (for now), but don't want to use a pickup coil or HALL or anything to sense the peek of the waves, I just want to short multipletimes but not only in the peeks, I want to short the gen coil also in the medium between the peeks and 0. I am attaching a picture that just made to show what I want to do.

[RS_]

you know, after thinking about it a bit, it may only take one set of mosfets to short eather pos or neg peaks.... but a different front end on the timer circuit to see the neg going zero crossing, as well as the pos going zero crossing to short both peaks using the same timer circuit and set of mosfets.

When i was doing this, the magnets on the rotor were all north out, and i only shorted the north peak......

[RS_]

it takes 2 mosfets to short the coil on ether pos or neg peak, and use a diffrent set of mosfets for pos and neg peaks..... study my coil shorting SCH........ and make one for the pos and one for the neg peak with a trigger timer pulser for each
like shown here

https://sites.google.com/site/alternativeworldenergy/shorting-coils-circuits

[AlvaroHN]

Thank you RS I will try to join that forum.
I looked the google site of the coil shorting when you post it the other day, I learned that I need to use 2 transistors/FETS to shot the coil /because of the positive and negative sine wave.

[RS_]

Alvaro,
the circuits i posted on here, focused on the coil shorting circuit lay out in a Pro Sch that every eng. can look at and understand vs the Konehead component drawings... I did not focus on the timing part of the circuit

this page shows a simple coil short circuit that only shorts 1 time per peak, and shows a scope shot of that peak short and the ringing that turning off the short produces....

https://sites.google.com/site/alternativeworldenergy/shorting-coils-more

this page shows a 555 timer IC based muilty pulse per peak circuit,
it also shows another muilty pulse per peak circuit based on other types of timer IC's

https://sites.google.com/site/alternativeworldenergy/sinewave-peak-coil-shorting-circuits

The problem with the 555 timer circuits, is they cant track changes in RPM, and thus cant ramp up to operation speed that they are tuned to, nor can they adapt to changing operation speeds once tuned to a given RPM, (they can do tracking if a lot of other circuitry is added)

I think that the 2nd circuit by RHP can ramp up to speed and adapt to changing speeds, but i have never built this circuit so i dont really know.....

If you join the EVGray Yahoo group and look in the files section, there are many other muilty pulse per peak circuits. and Konehead and the ppl on that fourm will answer your questions, or point you to posts where your questions are already answered

Bradley, the 2nd pulse is on top of the first highest peak of the oscillation that opening the short creates, helps to push again, not cause back emf drag.....read the EVGray fourms for more info from Konehead and many others that are doing this for a better understanding of this subject

[AlvaroHN]

didn't anwser about my opto, this is the datasheet http://www.vishay.com/docs/83725/4n25.pdf

I am learning to read datasheets, could it be 5 volts?