The stability and foamy slag indicator is based on harmonics calculations.
A FFT is performed on each phase and four +/-10V analog outputs are delivered to a PLC for example.
Out 1 – 2 – 3 : Phases 1 – 2 – 3 Stability index
Out 4 : Foamy Slag Indication (0 – 100%) 100% 0 is no foamy slag and 100% is excellent foamy slag.
FFT Calculation
Stability Index