The 803-B8W Rotating Cam Limit Switch is a heavy-duty control switch by Allen-Bradley used with machines with repetitive cycles of operation and used in applications where machine motion corresponds with shaft movement. The device uses a cam mounted on a rotating shaft for operation, and as the shaft rotates, the cam actuates circuit contacts. It is suitable for heavy-duty and long-life industrial applications, and like all Allen-Bradley Bulletin 803 devices, it comes with a cast iron side plate that is made for harsh and rugged industrial environments. It has 8 independently-operated cam assemblies with adjustable cam lobes and valleys, and it 8 circuits with snap action contacts, which is actuated as the cam rotates. The 803-B8W also has a rotating shaft with a 150 RPM base speed, and a keyway slot for connecting machines to the rotating shaft, and it comes with a contact-mounted cam roller which activates the circuit as the upper cam segment brushes past it.

The 803-B8W has a can activation duration (dwell time) that is determined by the size of the cam lobe, and when the cam lobes are aligned, the device achieves the minimum dwell time, and when they offset at the maximum angle, it achieves the maximum dwell time. The timing, which is the moment of can activation measured in degree, is determined by the position of the cam on the rotating shaft, with reference to the position of the keyway. The 803-B8W has internal adjustment settings for both timing and dwell time, and it also has an externally adjusted sprocket, which provides the means for changing the relative position between the driving mechanism and the shaft. The 803-B8W has a functioning temperature range of -30 to 66 degrees Celsius (-22 to 150 degrees Fahrenheit) without impeding contact performance, and it has a storage temperature range of -30 to 93 degrees Celsius (-22 to 200 degrees Fahrenheit). The device has a net weight of 16.3 kilograms (36 pounds), with shipping dimensions of 311.2 x 144.5 x 200 millimeters (12.25 x 5.69 x 7.88 inches), and it has CE, UL, and CSA certifications.