Effects of Recirculating BEMF to Coil

[gotoluc]

Hi David,

I was out most of today and now back. Do you have a relay?

If so! does it have double poles (contacts) If so You can use it as an oscillator to switch your negative feed of your PWM to try to measure where the power is coming from.

If you have the relay and need help to connect it, let me know and I can make a diagram.

I'm off to dinner but should be back in 45 minutes.

Luc

[gyula]

David, would you mind showing the schematic of your pwm that runs from the 9V battery? IT would help me to see clearly I hope.
Sorry if you have uploaded the pwm schematic some time ago, I did not follow this thread closely.

Thanks, Gyula

EDIT I have to leave now but will return tomorrow.

[rave154]

gyula,

see this attatchment for the pwm circuit...

GOTO, i have two 12V relays,

looking at the bottom of therm at the pins......it looks like this..

: :::

left hand two pins are the coil..... the rest are two switches....as the one disconnects the other connects (I think)

thanks for the help

[rave154]

a quick summing up

just to sum up....before moving noto the relay/switching thingy...


it seems.....that the gotoluc circuit is about....ohh...something like 95% efficient.....ie:- 5.56V measured directly acorss bulb on the bedini cap......then.....putting bulb into GOTO's circuit ( with cap for DC measure ).....got 5.46 'ish....ok......pretty efficient...


.. however.....ive been playing around ( while waiting for help with the switching thing )......with different combinations of coils ( yes more than one coil ) and also centre-tapped transformer coils...using the secondary as the main coil.....and then attachting a bulb to the centre tap of the secondary....and probing around.....but.......i will leave this till later because i want to nail whats causing this almost photo-flash brilliant flash from the bulb that has only a small draw on the voltage of the bedini cap..and no extra draw on the amperage of the bedini circuit as a whole that i can see....it really is BRILLIANT btw.......painful to look at in fact after about 2 or 3 flahses, not quite up to the discharge of GHST's gray tube discharge.....but......still VERY BRIGHT for such a small lowering on the voltage of the bedini cap....its puzzling to me.

anyways......onwards and upwards as they say...

Ahimsa for now

Goto, i wil be here for at lkeast another hour, probably more ( you have yahoo messeneger or the like btw? )

DAvid. D

[gotoluc]

Yes, these should work well too.



Ohm's law is the minimum all need to learn Luc. Without it, it's like walking in the dark without a light. Use this as your starting point if it helps:

V = I x R (easy to remember "VIR")
Which is: Voltage is equal to current times resistance.

By simple manipulation, you can solve for any of the 3 parameters. For example: I = V/R (current is equal to voltage divided by resistance).

So for R3, you have measured the voltage across it, and you know the resistance, so you can calculate the current I from the above equation.

You measure the voltage across the output capacitor C2, and that gives you another voltage to use in the power equation which I keep writing in all my posts (hint hint ):

P = V x I (Power is equal to voltage times current)

So from the above, we have calculated the current I in R3, and we measured the voltage across C2 which now provides us the two values to plug in to the power equation.

In the diagram I posted, let's say the measured R3 voltage was 100mV and the measured voltage at C2 was 1.45V.

First the current: I = 100mV/10 Ohms = 10mA
Second we already measured VC2 as 1.45V
Third: P(in) = 1.45V x 10mA = 14.5mW of power.


Yes, this the P = V x I I have been chanting all along. V/R is I (as I mentioned above).


I hope I didn't say that, that is not correct


No apologies necessary



It's actually keeping the current through R3 "smooth" (or flat) so it is easy to read with any meter. The voltage at C2 should already be fairly steady, so again easy to read with a meter. So now you have two easy to read values which when crunched through your calculator will give you an accurate value of power taken from the source battery or source supply.

.99

Thanks once again .99 for taking the time to explain in more details the correct calculation steps

I may no longer be the same

[rave154]

Grrrr

dammit, i just blew 3 bulbs in a row !!!!!!!!!!!! none left !!!!!!!!!!!!!!!!! GRRRRRRRRRRRRRRRRRRRRRRR !!!!
ill be back tomorrow with a barrow full of bulbs

Ahimsa for now

David. D

[poynt99]

Thanks once again .99 for taking the time to explain in more details the correct calculation steps

I may no longer be the same

Neither will I


.99

[gotoluc]

dammit, i just blew 3 bulbs in a row !!!!!!!!!!!! none left !!!!!!!!!!!!!!!!! GRRRRRRRRRRRRRRRRRRRRRRR !!!!
ill be back tomorrow with a barrow full of bulbs

Ahimsa for now

David. D

Hi Dave,

I was wondering how your bulbs could take such a hit causing blinding light and not burn out You're going to have to get some that can take more power.

I made a video for you to explain how to connect the relay to test the effect you have found.

Video Link: YouTube - Relay Demo for David

Hope this helps

Luc

[rave154]

GOTO,

just watched your video, its EXACTLY what i need !!! beautiful, adjustable for frequency and duty cycle with the realy ! BRILLIANT ( no pun intended )

5.42am here, going to have a few cuppas, wake up properly and get to it, i think i might have found a couple of spare bulbs :-)

Thanks so much for the vid and idea

David. D

[gyula]

gyula,

see this attatchment for the pwm circuit...

Hi David,

thanks for showing it and it seems that this pwm cannot drive the MOSFET gate properly? if we assume the bright flashes of your output bulb comes from the MOSFET's switching on and off by your hand triggering tests, then this should be done by the pwm automatically, right? Why does not do it?

In your pwm schematic the 555 is fed from a separate 9V battery, right? What do you mean by the green color modulation waveform, you refer to the output pulse from the 555 that drive the MOSFET?

First thing would be to choose a timing capacitance and resistance adjustment that gives the same repetition frequency you imitate by your hand for the bright flashes to occur when disconnect the negative, ok?
Second thing is try to short circuit the 220 Ohm resistor coming from pin 3 of the 555 and goes to the gate of the MOSFET, ok? This way you will not have a voltage divider towards the gate from the pin 3 output to get the pulse amplitude reduce. Because when you disconnect the negative of the 9V battery, then the rest of the pwm circuit surely supply a bigger (unloaded) positive voltage from somewhere to fully open the MOSFET (i.e. open much better than the pwm in itself is able to) and this situation should be remedied.

The relay suggestion by Luc is very good, but then why is your pwm used at all? This is what I wonder on.

rgds, Gyula

[rave154]

GOTO,

thanks for the video, works lovely, im just trying different caps to play with the frequency./.i was wondering, if i put a pot in series from the positive terminal of the relay battery.....as well as the cap across the terminals of the coil...would this allow changes on the fly?
anyways, it works and does indeed produce the bright flash upon disconnection.

Gyula,

thank you for your suggestions.....are you ready for this?????

leaving the relay out of the circuit for the time being, just running the bedini & pwm & flyback circuit....

while its running, if i pull the lead the comes from the mosfet source-to-battery begative OUT of the breadboard....the bulb goes out quietly with NO flash.

if i pull out the lead going to the mosfet gate, again bulb goes out quietly with NO flash..

if i disconnect the lead going from the mosfet drain to the bottom of the coil, bulb goes out quietly with NO fllash.

if i disconnect the lead going from the positive of the bedini CAP to the top of the coil, the bulb goes out quietly with NO flash.

ONLY when i disconnect the negative lead of the pwm circuit from the negative terminal of the 9V battery does the bulb go out with an intense flash....also, the flash is produced when i disconnect the poitive lead of the PWM circuit from the positive terminal of the 9V battery.

very odd.

David. D

[rave154]

a small video

a quick video of whats happening..

YouTube - bedini gotoluc 1a

excuse the mess !!!!!!!!!!!!!!

[gyula]

Hi David,

Thanks for your efforts but very sorry I am unable to figure out your total setup when you pull out the wire(s) and the lamp flashes up. Would you mind indicating with an arrow or in a different color in the schematic the exact two pieces of wires in both cases when you see the flashes?

Sorry for this.
rgds, Gyula

[gotoluc]

Hi David,

Thanks for your efforts but very sorry I am unable to figure out your total setup when you pull out the wire(s) and the lamp flashes up. Would you mind indicating with an arrow or in a different color in the schematic the exact two pieces of wires in both cases when you see the flashes?

Sorry for this.
rgds, Gyula

Hi Gyula,

from what I understand it happens when he disconnect or connects the positive or negative of the 9 volt battery that feeds the 555 circuit. We can see the energy is coming from the Bedini output cap but since it drops a small amount in voltage compared to the amount of light it is worth investigating. It could be the DVM is not fast enough to show the real numbers but by using the relay he should have a more stable result therefore be able to get a better voltage reading at the Bedini output cap. One way or the other, if he can get the output bulb higher then 6.5 volts David will have something very interesting.

Luc

[gotoluc]

Great video demo David

Thanks for sharing

Luc