Key ratings and what they mean for fit
The 3RT1046-3KJ84-0LA0: The AC-3 rating of 55 kW at 500 V is the headline motor-switching figure — it tells you this contactor can handle the inrush and break the running current of a standard squirrel-cage motor up to that power. At 400 V, the AC-2 rating of 45 kW covers slip-ring motor applications where the starting current is lower but the switching frequency may be higher. The AC-4 rating of 80 A at 400 V is the figure to check if the contactor sees frequent reversing or inching duty, because that duty cycle generates more arc energy. The mechanical life of 10,000,000 operations is typical for this frame size; the electrical life will be lower and depends on the switched current and duty class. The control circuit is rated at 72 V (likely AC or DC — the evidence does not specify the kind, so verify against your control transformer or DC supply). The auxiliary contact ratings are given at several voltages: 10 A at 24 V, 6 A at 230 V, 3 A at 400 V, and 1 A at 110 V. These are the maximum continuous currents the auxiliary contacts can carry at those voltages; for inductive loads like contactor coils or small relays, derate per the manufacturer's curve. The contactor is rated for pollution degree 3, which is the standard for industrial environments where conductive pollution or dry non-conductive pollution that becomes conductive due to condensation can occur. The operating temperature range is -40 to +70 °C, and storage range is -55 to +80 °C. The IP00 rating on the front and terminals means it is not protected against dust or water ingress — it must be mounted inside a panel with a suitable enclosure.
Mounting and wiring
The contactor mounts via screw and snap-on onto 35 mm or 75 mm standard mounting rail. Side-by-side mounting is permitted, which is useful for building compact motor starter assemblies. The main circuit terminals are screw-type, accepting 2x (10...50 mm²) stranded or 2x (2.5...16 mm²) solid/stranded. The auxiliary terminals accept 2x (0.25...2.5 mm²) solid. The dimensions are 145 mm high, 95 mm wide, and 191 mm deep — the width is the critical panel-space dimension when laying out multiple contactors side by side.