What this contactor is and what its ratings mean
The Furnas A30-30-10-36 is a 3-pole, non-reversing across-the-line contactor rated at 55 amps, with a 220V AC coil and one normally open auxiliary contact. The 220V AC coil means the magnet assembly is designed for a 50/60 Hz control supply at that nominal voltage; the coil holds in at the rated voltage and drops out below the manufacturer's pick-up threshold, so verify your control transformer sizing against the coil inrush.