The Siemens 6SL3520-1XA20-3AF0 is a SINAMICS S120 drive module carrying a 57S 150% overload rating — meaning it can deliver 150% of its rated current for 57 seconds during heavy load transients, a spec that matters for sizing on high-inertia loads like centrifuges or crushers where the breakaway torque exceeds running torque.
The 57S 150% overload capability is the key selection parameter: it defines how long the drive can sustain a 50% current surge above its base rating. For a motor driving a loaded conveyor start or a pump with a high breakaway torque, that 57-second window covers the acceleration ramp without tripping. If your application requires sustained overload beyond 57 seconds, you would need to step up to a higher base-rated module in the S120 family.