GT150L150A is a differential bimetallic thermal overload relay designed to protect AC circuits and motors against overloads, phase failure, long starting times, and prolonged stalling. This 150AF frame-size relay features a 110-150A setting range with lug terminal connections and operates at a rated operational voltage of 690V with rated insulation voltage of 690V and impulse voltage of 6kV. The relay incorporates three poles with three bimetallic heaters, trip class 20 protection, and includes manual/automatic reset capability with trip indication, stop, and test functions. It provides auxiliary contacts (1NO+1NC) for circuit control and operates reliably across a temperature compensation range of -5°C to +40°C with IP 20 degree of protection. The GT150L150A is commonly used in industrial motor control applications where reliable overload protection and phase failure detection are essential for equipment safety and longevity.