The 803-B12 Style B Rotating Cam Limit Switch is a heavy-duty control switch by Allen-Bradley with 12 independent operated cams and 12 heavy-duty control circuits. This cam switch is used with machinery with repetitive cycles of operation in operations where the machine’s motion correlates with the shaft operation. The 803-B12 has a shaft-mounted cam which produces contact actuation when the shaft rotates, and it is suitable for rugged and long-term industrial operations. It has 12 control circuits which have 10A snap action (1 NC, 1 NO) contact with 12A/1.2A MAKE/BREAK AC contact ratings at 600 Volts AC, and 0.1A DC contact rating at 550 to 600 Volts DC, and it comes with a spring-loaded cm roller assembly, which is mounted on the 10A (1 NC, 1 NO) contact. The 803-B12 has a 150 RPM rotating shaft speed and the shaft is supported by over-sized ball bearings, a keyway which connects the shaft to the moving machine parts, and it has 12 independent cam assemblies, with adjustable cam lobes and cam valleys. The circuits activate when the shaft rotates and the cam lobes brush against the cam roller, and they deactivate when the cam valley passes under the cam roller, and the duration of the cam activation (dwell time) depends on the size of the device’s cam lobes.

The 803-B12 has a maximum dwell time when the cam lobes offset at the maximum angle, and it has a minimum dwell time when the cam lobes align. It has a timing (when the cam activates the circuit), which is determined by the position of the cam relative to the keyway, and the device has a cam duration range of 14 to 346 degrees. It has internal dwell and timing adjustments, and it has a left shaft extension, which is standard for all Style B devices. The 803-B12 has a functional temperature range without hindering contact operation of -22 to 150 degrees Fahrenheit, with a storage temperature limits of -22 to 200 degrees Fahrenheit, and it is enclosed in a NEMA Type 1 indoor enclosure. The 803-B12 weighs around 21.3 kilograms (47 pounds), with total dimensions of 411.2 x 144.5 x 200 millimeters (16.19 x 5.69 x 7.88 inches), and UL, CSA, and CE certification.