Schneider Electric B62.0

The Thermal Unit, Type S, Type B, is specifically engineered to safeguard motors, controllers, and branch-circuit conductors from overheating caused by sustained over-currents, including locked rotor currents. This unit effectively relies on a melting alloy mechanism, which allows it to trip under overload conditions within 20 seconds or less, adhering to established trip curves for Class 20 thermal units.

It features a one-piece construction where motor current traverses a small heater winding. Under overload scenarios, the heat generated melts a special solder, enabling a ratchet wheel to disengage, thereby opening control circuit contacts along with the motor contacts. This function is critical in preventing damage to the motor and associated circuit components from excessive currents, which are typically managed by branch circuit fuses or circuit breakers.