Schneider Electric's Square D 9055-AO-125-R Magnetic Control Relay is an open-type magnetic current relay in the 9055 family, used to provide overload protection and control in open-type motor starters and similar circuits. The AO125R variant designates a 125 A class device, with documented use up to 600 V AC in open-type configurations (some listings cite a 420 A rating for this model). In crane and other heavy industrial control applications, 9055 magnetic relays deliver magnetic trip protection as part of the motor-control circuit.
