40-50 A FLA range, 3-phase, UL508
The ABB MS450-50E is a manual motor protector (MMP) covering a 40.00-50.00 FLA range, 3-phase, rated 600 V under UL508. It integrates short-circuit protection and phase-failure detection into a single device, eliminating the need for separate fuses or overload relays on the line side. Trip class is selectable between 10 and 20 — Class 10 for faster protection on motors with short acceleration times, Class 20 for higher-inertia loads like conveyors or crushers. The adjustable dial lets you set the trip threshold within the 40-50 A band without swapping the unit.
UL508 listing covers the MMP as a self-protected combination motor controller. The unit carries short-circuit protection and phase-loss detection in one package, which simplifies panel layout and reduces wiring compared to a separate breaker-plus-overload configuration.
Panel fit and peer comparison
The MS450-50E is a DIN-rail mountable MMP in the MS450 series, designed for 3-phase motor branch circuits up to 50 A. It provides both overload and short-circuit protection, so it can serve as the sole protective device in a motor starter circuit per UL508. The 600 V rating covers 480 V and 600 V nominal systems without derating.