73 A motor protection threshold
The ABB MS165-73 is a manual motor starter rated at 73 A, setting the overload protection ceiling for the connected motor load. This 73 A figure is the thermal-magnetic trip threshold — the point at which the bimetal element responds to sustained overcurrent before the motor winding temperature exceeds its insulation class.
MS165 series — motor branch circuit duty
Part of the ABB MS165 series of manual motor starters, this unit provides combined motor branch circuit protection — overload, short-circuit, and isolation in a single device. The 73 A rating suits it for medium-horsepower motor loads in industrial control panels, typically on DIN-rail mount alongside contactors and overload relays.