A system, a method, a device, and an apparatus include a control unit configured to determine contact resistance of one or more electrical contacts of one or more circuits, and remove, via a wetting current, residue on the one or more electrical contacts.

A method for cleaning electrical contacts of an electrical switching device includes displacing a first electrical contact element and a second electrical contact element of an electrical contact relative to each other so that the first electrical contact element and the second electrical contact element are in a closed position; and when the first and second electrical contact elements are in the closed position applying a waveform on the electrical contact so that the first contact element and the second contact element are excited to undergo a mechanical vibration relative to each other.

A system and method according to various embodiments can include a universal contact input status detection circuit. A voltage source wets a contact with a wetting voltage. A current mirror circuit is connected across an input of the contact to provide a constant wetting current over a wide input voltage range. The input voltage can be varied over a range wide enough to include both AC voltages and DC voltages. The current mirror circuit maintains the constant wetting current during varying wetting voltage inputs across the input of the contact. A wetting voltage sensor senses the wetting voltage provided to the contact so that the status of the contact can be determined.

A method for actuating an electromechanical switching element including a plurality of contacts, a coil with an iron core, and an armature includes: in the event that a predefined condition is fulfilled, in a switch-off process pulsing on and off or in the switch-on process pulsing off and on of the switching element is carried out repeatedly at a predefined time within an overtravel range such that a coil current flowing into the coil oscillates between a predefined maximum value and a minimum value so that the armature moves within the overtravel range and the plurality of contacts thereby rub against each other without becoming detached from each other. The minimum value is defined as a current value at a time at which the armature begins to detach from the iron core.