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.