The Textbook Behind the VIC, 6: one frequency only

Part 6 of 6 in The Textbook Behind the VIC: 1 · 2 · 3 · 4 · 5 · 6

Inductance neutralised by capacity

Fleming comes at resonance from the engineer's side: a condenser can cancel a coil's inductance, leaving a circuit that behaves as if it had resistance alone.

Hence a certain relation between the inductance, capacity, and frequency, causes the inductance to be neutralised by the capacity, and the whole circuit to be effectively non-inductive.

— Fleming, §7 of Chapter V, p. 399 (part 23)

And, for the leaky condenser of part 2 — a condenser with a resistance across it, in series with a coil — the catch:

It will be seen that the annulment is only exact for one particular frequency, and that change of frequency means a change in the value of r requisite to neutralise the inductance.

— Fleming, §31 of Chapter III, pp. 189–190 (part 11)

Read the other way round: for a given coil and condenser, there is one frequency at which they cancel, and if the condenser's leak r changes, that frequency moves.

Steinmetz puts the ideal case and its limit in two sentences, working an example where the series reactances exactly balance:

…absolute resonance takes place. Obviously, this condition cannot be completely reached in practice.

— Steinmetz, Alternating Current Phenomena, 1900, p. 68 (part 4)

What Meyer wrote, and built

Meyer's resonance is stated as a band, and he says what moves it:

The established resonant frequency is most generally in the audio range from 1 kHz up to and beyond 10 kHz; and is dependent upon the amount of contaminants in natural water.

— Resonant Action, WFC 422DA

Contaminants set the water's conductivity, which is Fleming's r. And as the cell gasses and warms, its capacitance and its leak both change during a run. By Fleming's §31 a fixed drive frequency would walk off the resonance, which is why Meyer did not use one. At the house meeting in New Zealand in 1989:

…we now electronically zero in to the resonant frequency of any form of natural water because it would change based on the contaminants within the water… It automatically scans it right in, locks right in the resonance and holds it there.

— New Zealand 1989, part 1

And on the gas management system, with the lock made visible:

…we also have a lock light so that when it does capture that resonant frequency, the light will be on, indicating that we're locked on the water cell, we're in resonant, and we're producing the gas.

— Stan and Stephen Meyer on the gas management system

A drive that scans for the resonance and locks to it is the correct engineering answer to Fleming's catch, and it is the same answer induction heaters and ultrasonic welders use today. Meyer's circuits were built to follow a load that the textbooks say will not sit still.

Syntony: tuning the circuits to each other

Fleming's same chapter goes on to Hertz's resonator and to Lodge's "syntonic" circuits, two circuits tuned to the same period so that one drives the other (§§9–11). The idea that a pulsed circuit should be tuned to the natural period of what it drives, rather than simply driven harder, was the front edge of electrical science in 1896. Meyer's "resonant action" belongs to that line of thought, whatever one concludes about what is resonating in the water.

The six parts, summed up

None of this proves anything about what happens inside the water. What it shows is that the circuit Meyer drew, and the words he used for its parts, are ordinary, well-founded electrical engineering of the kind Fleming and Steinmetz taught, and that each part comes with a condition that can be measured on the bench. The archive would like the measurements.

Start again at part 1, or watch the NeuralStan episodes that go with this tutorial.