What the ratings mean for fit
The 3RB1246-1QG30: The 6.3-25 A range sets the motor FLA it can protect — set the dial to match the nameplate. Class 5-30 means the trip curve is adjustable from fast (Class 5, for short thermal time constants) to slow (Class 30, for high-inertia loads like fans or centrifuges). The integrated ground-fault detection is a step up from a basic bimetallic relay; it watches for leakage to ground and trips the monostable output. Manual-automatic-remote reset gives flexibility: leave it on auto for an unattended line, or force manual reset after a fault for a safety check. The overload warning output lets a PLC log an approaching trip before it happens.
Integration notes
Individual mount — it clips onto the S00/S0 contactor or a DIN rail. Screw terminals on the aux circuit; the main circuit uses a current transformer, so no direct pass-through bus bars. Wires up clean if you keep the CT wiring separate from the aux control wiring to avoid induced noise on the 110-120 VAC coil circuit.