Muller Dynamo

[penno64]

@penno64
Just for my curiosity can you please answer me to the folowing questions?

What is the dimenstions of your coils?
What is the dimension of your core and type of material?
What type of wire and how many turns?
What size are the magnets and what grade?
What is the speed you get at 12 volts input?
What is the speed you get at 6 volts input?
Voltage... not important.


at 12v   992 rpm

at 6v   446 rpm

20v - 1606rpm - 1.7v after diodes with 12v/100ma lamp

Romero, it is I who should be thanking you.

Penno

[nvisser]

I propose a double rail coil driver circuit that I use to power my Muller dynamo replica. Soon I will make some pictures and a youtube video. Good luck everyone!

Keykhin
What is the function of the 2 diodes between the fets and coils?
Vissie

[gyulasun]

Keykhin and Collapsingfield,

Please understand what application field the 1N4000 series diode family was developed.  It is a general purpose rectifier for mains voltage (50 and 60 and maximum perhaps up to 400 Hz frequencies).  Using it in the some kHz and higher frequency ranges, an increasing loss appears in heat form, it would be burned in switch mode power supplies in place of  Schottky or fast recovery Si type diodes.
Once I tried to use an 1N4001 at 16 kHz for rectifying 0.6A as a temporary substitution and it become very hot within some seconds but worked. So in the some kHz and higher range they are indeed KRAP. (But they were NOT manufactured for those 'higher' frequencies.)

Collapsingfield:
In a parallel combination of a hefty diode bridge and 1N4001s, where the bridge has higher forward voltage drop than the 1N4001, it is ok that the 1N4001 would open earlier but not due to its faster speed but just due to its less forward voltage wrt the bridge diodes. Its switching speed would remain at the same low frequencies listed above.

Regarding the difference between 1N4001 and 1N4007,  apart from the reverse voltage ratings, although the data sheet does not differentiate between them in any other respect, I think that a 1N4001 or 4002 can have a bit less forward voltage drop than a 4007. I base this speculation (did not confirm) on other diode types where their data sheet does mention such differences, the lower reverse voltage types within the same diode series have some ten to hundred millivolt less drop than the higher voltage members of that diode family.
This may answer e2matrix question on this, but it is my speculation only.

rgds,  Gyula

[baroutologos]

I want to add my experience regarding the coil shorting at peaks concept.

I was involved in this series of experiments for some time. As usually i started with solid state setups, creating a resonator (Kacher like one) that has a suitable L and a cap. Resonant frequency could be adjusted between 4-20Khz. I had choosen some 10 Khz arbitrarily. Then resonator had another coil L' coupled on it, that was shorted by a Mosfet after the FWBR to a AC cap. A circuit was devised so the cap to be discharged from a peak value A to a baseline value B.
The value B was considerably higher than the AC value the L' coil could ever achieved without shorting. Discharging was made to a bulb.

Despite technical problems that i dealt with them, i noticed nothing extraordinary there.
http://www.youtube.com/watch?v=Gf0ZTxj9jTk

Then after following a advice on the topic, i dug up the Perepiteia motor-rotor i had and proceed with the same concept at mechanical setup.
In the mechanical setup, rotor is made out of alluminium (conductive) and has 12 neo-magnets in NSNS polarity.
Shorting was made by using two mosfets wired in bidirectional model (see diagram below) and spike was harvested to a cap. Cap is discharge in a similar to solid state version to a bulb having a third mosfet that is triggered at peak value 90volt and keeps a base voltage of 60 volt. Pick up coil is outputting a peak of 15 volts or so.

Again, setting rotor's freewheeling at particular speed as a baseline consumption and experimenting with adjustable coil shorting timing and duration by the means of a sensing coil placed at 180 degrees to the pickup coils and suitable circuit plus the usage of a 555 timer in monostable mode i achieved a fully adjustable short.

Again, in this particular setup failed to observe any energy gain (calculating losses etc in the equation). From a critical point of view my setup suffers from a conductive rotor and the inability to adjust spacing of rotor to coils. On the other hand coil cores are made out of ferite. Windings tested were a solid wire (40 turns 18 awg and 100 turns 24 awg biffilar)
http://www.youtube.com/watch?v=2zGjgJEyhgo

So far, in my experience have not seen any merit in it.
My impression is that, if peak-shorting lead to speed up, it should a plain dead continuous short should also lead to a spead up.

[excessAlex]

Excuse me so much I know .. these words are completely off topic .. But to have a laugh...

O Romero, Romero! Wherefore art thou Romero?
Deny thy father and refuse thy name;
Or, if thou wilt not, be but sworn, my Muller motor replica