Allows double switching of double conductor.
'closed' and 'open' determine the mechanical switch-position.
Electrically the switch is on if it is 'closed', whereas it is switched off,
if it is mechanically fully 'open' (after a given opening duration) and the corresponding phase-current crosses zero.
Contains replaceable single-line breakers with replaceable tanh arc-voltage, i.e. a constant electric field strength E for large currents and a small-signal Ohmic resistance R.