The Eaton A12-30-10-51 is a 3-pole, non-reversing across-the-line contactor with a 480V AC coil and one normally open auxiliary contact. Rated at 11A, it's sized for smaller motor or resistive loads in a control panel — the 480V coil pulls in directly from a 480V control transformer without an intermediate relay.
The 11A rating governs the continuous current the main poles can carry — match it to the full-load amps of the motor or the resistive load current, not the inrush. The 480V AC coil means the contactor picks up on a 480V control circuit; verify your control transformer secondary matches that voltage. Three poles switch all phases of a three-phase load. The single NO auxiliary contact provides one feedback or interlock signal back to the PLC or safety circuit.