The 139-DO-NFS-FLC has a variety of applications to reliably protect the motor and associated mechanical equipment. The undercurrent feature detects a situation where the discharge valve is closed or when there is a loss of suction to provide additional personal safety and mechanical pump protection. 
This feature also detects a loss of air flow in mines or a loss of flow in steam generating boilers. The rapid trip feature protects the motor components in the event of a mechanical jam. the ground fault feature is capable of providing personal protection from a shock hazard by detecting winding shorts or leaking currents due to moisture. The thermal memory lockout feature also allows the 139-DO-NFS-FLC to provide motor protection from operator abuse. 

The full load current option is an additional option that must be specified during ordering of the base unit for inclusion. This FLC option provides the unit with a 4-20 mA full load current. 

The RTD input of the 139-DO-NFS-FLC is a sensor user supplied platinum copper nickel RTD. The alarm temperature can range from zero to 180 degrees C, with a 110 degree nominal temperature.