An electrical connector connects to a mating connector in a first direction. A torch electrode acting as a first electrode and the arc-treated material made of graphite and acting as a second electrode are arranged opposite to each other. Within each transducer group, each transducer is actuable via application of a different phase-shifted variant of a local oscillator signal to the transducer. A torque rod assembly extends between and is operatively connected to third and fourth grain tank extensions.