2013 R&D 100 Winner
NETL Arc Position Sensing (APS)Vacuum arc remelting (VAR) is the primary method for melting and refining specialty metals for advanced applications. Defects in the ingots from VARs can cause catastrophic failure in their end use, and are often caused by solidification problems due to operational characteristics. Previously, these conditions could not be identified during furnace operations, requiring ingot manufacturers to perform extensive testing on all ingots. National Energy Technology Laboratory (NETL)’s Arc Position Sensing (APS) technology, developed in collaboration with ATI, allows operators to digitally monitor arc location during melting in real time through non-invasive magnetic sensing.

The technology uses NETL’s patented electric current locator (ECL), which resolves unknown or diffuse current paths in applications where direct access to the current path is not available. To accomplish this, APS technology utilizes the Maxwell-Ampere Law, relating magnetic fields to electric currents. The ECL also leverages the Biot-Savart Law, which describes the relationship between a steady line current source and magnetic flux density at a point. This allows the technology to resolve current paths which subject to variances in the magnetic field due to superposition and geometrical issues.

Electric current monitor

National Energy Technology Laboratory

Development Team

The Arc Position Sensing (APS) development team (l-r): Paul King (NETL), Chris Nordlund (ATI Metals), C. Rigel Woodside (NETL).


The Arc Position Sensing (APS) Development Team
Paul King, Principal Developer, National Energy Technology Laboratory
C. Rigel Woodside, Principal Developer, National Energy Technology Laboratory
Chris Nordlund, ATI Metals