The 803-A5RHRE Rotating Cam Limit Switch by Allen-Bradley is a heavy-duty control circuit device, with a speed reducer feature and a right-hand shaft extension modification. It is used with machinery with repeating cyclic operations in a process where motion corresponds to shaft rotation. The device is suitable for heavy-duty and long-lived machine operations, and it operates using a cam mounted on a rotating shaft, which actuates contacts as the shaft rotates. The 803-A5RHRE comes with 5 control circuits with cam-opened 25A NC double-break contacts with both AC and DC contact ratings and a spring-loaded cam roller. It has a rotating shaft with a 150 RPM base shaft speed, and 5 independently-operated cam assemblies with variable lobes and valleys, and a keyway which connects moving machines to the shaft. When the shaft rotates, the cam lobes press against the cam-roller assembly, activating the circuit, and when the cam valley passes by the cam-roller, the circuit is deactivated.

The duration of the cam activation (dwell time) which depends on the size of the cam lobes. It can either be at the minimum or the maximum, depending on the angular alignments of the lobes. It is minimum when the lobes are aligned perfectly, and it is maximum when the lobes offset at the maximum angle. The 803-A5RHRE has a timing measured in a degree which determines when the rotating cam activates the circuit, and the timing itself is determined by the position of the shaft-mounted cam, relative to the keyway position. It has internal dwell and timing adjustments which determine the machine’s operation, and it has a cam duration range of 14 to 346 degrees. The 803-A5RHRE comes with a left-hand shaft extension modification, and it is fitted with a speed reducer, with a 120 to 1 gear ratio. It has a functional temperature range between -30 and 66 degrees Celsius (-22 and 150 degrees Fahrenheit), with a non-operating range between -30 and 93 degrees Celsius (-22 and 200 degrees Fahrenheit), and it is fitted with a cast-iron side plate, and a NEMA 1 rated enclosure. The 803-A5RHRE weighs approximately 11.3 kilograms (25 pounds), with shipping dimensions of 211.1 x 144.5 x 200 millimeters (8.31 x 5.69 x 7.88 inches), and it is CE, UL, and CSA certified.