STEORN DEMO LIVE & STREAM in Dublin, December 15th, 10 AM

[Low-Q]

In general we can say that ANY claim of over unity is a scam, joke, fake, whatever. Personally I have never let such devices catched my eye, especially when running with batteries, and a bunch of wires. The only machine I find interesting is Finsrud's perpetuum mobile. But since no one really know EXACTLY how it works, I guess there must be some sort of energy input - who Finsrud himself might not understand. My guess.

[verpies]

I just found that thread (over 2 years after it started ;/) and read 104 first pages out of 267.

At this point I can't help to ask you guys why is the width of the pulse energizing the coil (essentially an LR circuit) so long relative to the L/R parameter of the circuit (a.k.a. Tau) ?

From the energy efficiency point of view - it makes no sense to energize the coil for longer than 1.1513 Tau because after that time the energy dissipated in the resistance as heat starts exceeding the energy stored in the coil.

This break-even point happens when the current through the coil reaches 68% of the V/R limit, which is long before the current pulse levels off (...and appears flat and "rectangular").

If the energy in the coils is to be recovered than this break-even point happens two times sooner ( 0.5757 Tau) because during the recovery time the energy is also wasted in the resistance at the same rate.

A rectangular current pulse visible on a scope is "bad news" because any indication of flatness is a sure sign that the V/R limit has been approached and the energy dissipated in the resistor GREATLY exceeds the energy stored in the magnetic field of the coil.

An ideal pulse (below 0.5757 Tau) should have a rounded triangle shape.

[kristy77]

This blog is really great, keep creating good info.

[verpies]

This might help some experimenters who are pulsing inductors (e.g. Orbo's stator coils) and 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 0.5*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 (V^2)/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 0.5*L*((V/R)^2) limit but the energy dissipated in the resistor increases ad infinitum at the rate (a.k.a. power) equal to (V^2)/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.


LA PUENTA:
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 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.
E_TOT = Total energy delivered by the supply to the series RL circuit.
E_L = Energy stored in the inductor as magnetic field
E_R = Energy dissipated in the resistance as heat
P_L = Instantaneous Power (energy flow) flowing into the inductor
P_R = Instantaneous Power (energy flow) dissipation in the resistance
i_L = The current flowing through the inductor (and resistor)
       ( I can post the relevant time-domain equations on request )