To safeguard essential machinery (like steering gear) by automatically disconnecting non-essential services (like AC or galley power) during a partial overload.
Cleaning air filters, removing dust from the rotor, checking the air gap (typically 1.5 to 2 mm) with a feeler gauge, and inspecting slip rings and carbon brushes. Safety & Regulations Meo Class 4 Electrical Oral Questions And Answers
Steering gear is unique because it must have a short-circuit trip but only an overload alarm (typically at 150%) rather than a trip, to ensure it doesn't stop suddenly during critical maneuvering. To safeguard essential machinery (like steering gear) by