The 803-P3LH Rotating Cam Limit Switch is a heavy-duty control circuit device by Allen-Bradley used with machinery with dedicated cycles of operation in an industrial process where the machine's motion equals the shaft rotation. It is built for long-life, heavy-duty operation, and it utilizes a shaft-mounted cam operation, which produces actuation as the shaft glides. The device is suitable for processes like assembly and packing, steel forming, injection molding, and punch-press applications. The 803-P3LH has 3 circuits with a cam-opened 25A normally-closed double block contact, with AC and DC contact ratings, and it has a rotating shaft with a 400 RPM shaft speed and a left-hand shaft extension. It has 3 independently-operated cam assemblies, with less operating options, and it has an adjustable lower (valley), and an adjustable higher (lobe) cam segment. The device also comes with a tact-mounted, spring-loaded cam roller, which produces contact actuation as the cam lobe brushes against it, thereby activating the circuit, and it has a keyway (shaft slot) which connects the rotating shaft to the moving machine parts.

The 803-P3LH has a dwell time corresponding to the total amount of time for which the cam lobe activates the circuit, which in turn is influenced by the size of the cam lobes. The switch also has a cam timing, which is the moment when the cam activates the circuit, and it is also determined by the position of the cam with reference to the keyway position/Top Dead Center. The 803-P3LH has high-speed, low-cost, internal dwell time and timing adjustments, which determine machine operation, and it comes with a factory-modified left-shaft extension, unlike the standard right-shaft extension. It has a working temperature range of -30 to 66 degrees Celsius (-22 to 150 degrees Fahrenheit), with a storage range of -30 to 93 degrees Celsius (-22 to 200 degrees Fahrenheit), and it comes with a NEMA Type 1 indoor enclosure. The 803-P3LH weighs approximately 6.1 kilograms (14 pounds) with less operating cam, and its total shipping dimensions are 217.5 x 181 x 138.1 millimeters (8.56 x 7.13 x 5.44 inches).