The patented Arc Voltage Drive or AVD™ technology is new to the Thermal Spray industry and is proprietary to Thermion®. It is a new method of providing electrical power to the wire drive motor, in such a manner that control of the arc gap is absolute during metalizing. The output voltage of the power unit has a direct relationship to arc gap established between the two consumable wires that form the coating during metalizing. As changes occur in the system (such as heating of power cables, tip wear, incoming power variables, etc.), they automatically trigger the wire feed motor to react within milliseconds and maintain the established arc gap. This reaction is such that arc shorting of the two wires can never occur. Along with improving spraying characteristics of the arc spray metalizing process, unprecedented coating quality is achieved, due to the high density (low porosity) and defect free coating; one can produce mirror finished ground and polished coatings for the most demanding applications. Of equal important is that all wire diameters can be thermal sprayed through a wide range of spraying parameters, both voltage and amperage can be varied considerable and generally with one voltage setting on the power unit, the amperage (wire feed rate) can be adjusted near zero to maximum of the system for very accurate control of the spray job.