HF AC
V1 o--- ---o V2
| |
OOO
======= T1
OOOOOOO
| | |
i--> | | | <--i
-----M1------- | -------M2-----
| | |
o----C1---------o---------C2----o
| | |
F1 F2 F3
| | |
o---(+)DC1(-)---o---(-)DC2(+)---o
Fig. 1 - Method of superimposing AC signal
on DC electrolysis current
A frequent objective of electrolysis cell designs is to overcome the
DC bias required to push current through the interface layer between
the electrolyte and the electrodes while driving the principle
electrolysis current from an AC source. Figure 1 shows a method of
adding an alternating electrolysis driving current on top of a DC
bias in such a way the principle electrolysis current is driven by
the AC source.
The electrolytic cells in Figure 1 are designated M1 and M2. These
cells can be implemented as series multi-plate cells, so that large
voltages can be applied. DC power supplies DC1 and DC2 provide DC
potential right at the critical voltage level, where cells M1 or M2
just begin to conduct current and thus perform electrolysis. DC1 and
DC2 can contain protection diodes that prevent back current through
them. Filters F1, F2 and F3 isolate the DC power supplies from the AC
while allowing DC to pass These can simply be large inductors. The
center tapped transformer T1 provides current through M1 on one half
phase, and M2 on the other half phase. The core of T1 is not biased
on average by any DC current because any DC currents through the two
secondary windings cancel magnetically. Capacitors C1 and C2 are
provided to complete the AC circuit through the cells.
If M1 is exchanged with C1, and M2 exchanged with C2, in Figure 1,
then it is easy to see that M1 and M2 can be implemented as a single
series multi-plate electrolysis cell with the center plate attached
to the center tap of T1, thus avoiding multiple electrolysis cell
containers, gas feeds, etc.
Note that the voltage applied in the secondaries of T1 are
*incremental* to the voltage supplied by the DC power supplies. Note
also that, except for electrolysis cell internal resistance, the
active AC elements of the circuit are inductances or capacitances,
providing as large a phase angle as possible.
Horace Heffner
http://www.mtaonline.net/~hheffner/
