Romero's experiments and OU principles

[EMdevices]

There's a few things that experimenters should realize concerning coils (if they don't already):


1)  Litz wire is used for coils when it comes to high frequency applications that require  HIGH Q VALUES, which means that you want the ratio of inductance/resistance to be high.   Why do you want a high Q value?  So you can tune to a particular frequency and have great selectrivity (it tunes very sharply) and amplification as in AM radio tank circuits.   The multistrand Litz wire achives these objectives because it has a lower AC RESISTENCE (as compared to DC resistance.)    AC resistance is limited by the SKIN EFFECT, and this effect limits the usable cross section of the coil wire that carries the current, so using lots of tiny wires in parallel lowers the AC resistance, and thiner wires can than be used that carry current across their whole cross-section, so a better utilization of the wire.    However, we can achive the same lower AC resistance with regular solid wire, but unfortunately you will use thicker wires (because resistance is proportional to the circumference of the wire multiplied by the skin depth) but the inside of the wire does not conduct current and is a useless volume and mass and $ wasted especialy with copper prices being as high as they are, so this does not make sense in a high volume manufacturing enterprise, but for experimentation who cares, right?   So use of Litz wire is realy an OPTIMIZATION for high frequency opperation, but not necessarily exclusive of other methods.  (for example in antennas, we use large diameter hollow tubes


2)  A coil that has many layers of winding,  is not only a great inductor (at low frequencies only)   but becomes a great CAPACITOR at high frequencies.     The capacitance is not tens of pF, but possibly hundreds if not thousands of pF depending on size and number of layers.    As the frequency of operation goes up high,  from circuit theory we know the impedance of inductors  (jwL) goes UP,   but for a capacitor  (1/jwC) goes DOWN.  So, the equivalent circuit for a typical coil in Romer's dynamo, is realy a capacitor in parallel with an inductor and resistor in series.   So at high frequencies the inductance + resistance is shunted by the capacitance and is realy not effective at all ! 


3)  A comment about the dyanamo operation:    As I mentioned in my other posts,  the pulses from the coils occur at a high frequency , for example  5.76 kHz at 2400 RPM.   So we are operating at somewhat high frequencies but not too teribly high.   There are charts out there that show what size wire is necessary as a function of frequency and 100% skin depth.  (http://www.powerstream.com/Wire_Size.htm)      From this chart,  a solid wire of 0.8128 mm diameter is good up to 27 kHz, before the skin depth starts to limit the cross-section of the wire that conducts current (and hence the AC resistance starts decreasing relative to the DC resistance, but up to 27 kHz,  AC and DC resistance are pretty much EQUAL)    The bottom line,   no need to use Litz wire!    (unless something magical happens unaccounted by theory, of course) 


EM


PS,   In my opinion,  the interesting phenomena in this motor is

1) the short pulsing at high frequency, which is a type of COIL SHORTING at max voltage, and

2) the rapid speed of coil magnet alignments at a speed faster than the rotor speed, due to the 8/9 magnet to coil ratio, as I explained in other posts.

[neptune]

@EMdevices .That was a good solid post , full of wisdom ,but there is one point that needs consideration . You quote a frequency of5.76 kHz at 2400 RPM . However there is a sort of concensus that Romero`s machine worked at around 1200 RPM . So, a frequency of 2.88 KHz . Problem is , how did you arrive at that figure . There is a theory doing the rounds that the the "magnetic events" happening at a given coil happen at 8 times  as often as would appear at first glance . This is due to even number of magnets and odd number of coils . If you did not factor this in , then frequency becomes 8x2.88 KHz or 23.04 KHz . and this does not take into account the possible importance of harmonics . So Litz might yet be beneficial . Your comments please?

[romerouk]

This can be built with one solid wire too but we need to use capacitors...
Below are pictures with some of the coils I am going to use in my new project, single wire. Not all are ready, more work to be done.

[e2matrix]

That looks like some nice big coils Romerouk.  At least I think I'm seeing fairly large coils.  Hopefully some real generating power there ! 

Neptune,  you don't want to know about Hector unless you can handle some really harsh language and a slightly crazy sounding guy.  He does seem to have the mastery though on Rotoverters.  From what I've read though it's not an easy project unless you are bolt (or konehead or Hector)

[neptune]

@nul-points . Many thanks for your help in drawing the circuit diagram . My skills did not allow me to do it . Suggested component values .
Transistor is any small signal NPN , eg 2N2222 etc
c1 and c2 are10 nf
R1 =100k
R2 10k
C3 -10pf to 47 pf .
  The capacitor values may not be the best but it will work . Supply is 9 volts .
L1 is your coil under test . Measure output frequency with a frequency counter .
@e2matrix . Fierce language and a bit crazy ,eh ? Are you sure you are not confusing him with me ?