Allen-Bradley 509-AOD Motor Starter Contactor

Allen-Bradley 509-AOD is a NEMA-size 0, full-voltage, non-reversing motor starter (Bulletin 509) with a 120V control coil. This open-type, three-pole unit includes a eutectic alloy overload relay and is designed for direct-online starting of small three-phase motors, with the motor-side voltage rated up to 600V AC and a coil rating of 115–120V AC at 60 Hz. As a direct-online starter, it provides simple, rugged control for conveyors, pumps, fans, and other general machinery where reliable overload protection is required without soft-start features. The open construction is intended for panel-mounted installations and straightforward integration with standard control circuits, without built-in soft-start or VFD functionality. This classic Allen-Bradley solution offers direct-on-line operation with automatic overload protection via an eutectic alloy relay, making it suitable for compact, cost-effective motor control in a wide range of industrial applications.