Franklin Sub Tronic Single Phase Submersible System ProtectorFranklin Sub Tronic Single Phase Submersible System Protector Technical Specifications and Model Parameters The SubTronic1P range of control boxes has been designed as drop in replacements for conventional Single Phase motor control boxes. As such, it will work with standard pressure flow switches adding intelligence & protection to the borehole water system. Model Parameters Motor Rating (kW) Type 1phase 230V 50 HZ Model Number 0. 37 ST037CSR