A vacuum contactor unit is an electrical device that contains contacts in a sealed environment called a vacuum bottle. This sealed vacuum interrupter, when the switching takes place, allows for a fast, safe, and clean make or break action of the contacts in harsh, dirty surroundings.
One side of the vacuum contactor is movable, while the other side is fixed since its primary function is to make or break the connection between the load and the power source. Once the AC vacuum contactor is energized, the generated electromagnetic force pulls the movable contact to the fixed contact; then, the spring pulls them apart once de-energized. This operation is contained within the vacuum bottle, which has the arc and keeps contaminants outside.