The 803-B12RY05T01 Rotating Cam Limit Switch by Allen-Bradley is a heavy-duty circuit control device with a customized speed reducer and a standard left shaft extension. It is used with machinery with dedicated operation cycles where the mechanical motion is directly correlated with the shaft motion. The 803-B12RY05T01 is designed with a rugged cast iron side and it is suitable for heavy-duty and long-life industrial applications. It comes with 12 independently-operated rotating cam assemblies with adjustable higher (lobes) and lower (valley) segments, and 12 heavy-duty control circuits with a 10A snap-action contact. The 803-B12RY05T01 has a spring-loaded cam roller mounted on a contact base, and a rotating shaft with a 150 RPM maximum shaft speed, and a keyway for connecting the machine parts to a rotating shaft. The circuit is activated when the shaft rotates, and the cam lobes push against the cam roller, and it deactivates when the cam valley passes under the cam roller.

The duration of the cam activation (dwell) is determined by the size of the cam lobes, and it is at its maximum when the cam lobes offset at the maximum angle, and it is at its minimum when the cam lobes are aligned perfectly. The timing is measured in degrees, it is the moment of activation, and it is determined by the position of the cam on the shaft, relative to the position of the key. The device also has both internal timing and dwell time adjustments. It has a speed reducer option, with a special, factory-ordered gear ratio of 5 to 1, and a standard Style B left shaft extension. The device has a working temperature range of -30 to 66 degrees Celsius (-22 to 150 degrees Fahrenheit), with a storage temperature of -30 to 93 degrees Celsius (-22 to 200 degrees Fahrenheit), and it is enclosed in a NEMA Type 1 rated enclosure. The 803-B12RY05T01 weighs about 21.3 kilograms (47 pounds), with net dimensions of 411.2 x 144.5 x 200 millimeters (16.19 x 5.69 x 7.88 inches), and it has CE, UL, and CSA certifications.