The 803-F812TRH Rotating Cam Limit Switch is a Style F heavy duty circuit control switch from Allen-Bradley. It has adjustable cam operators and a left-hand shaft extension modification, and it is used with machines with dedicated operational cycles, in applications where the shafts rotating correlates with the machine’s motion. The 803-F812TRH is fitted with cast iron side plates, suitable for rugged and harsh industrial environments, and it utilizes a shaft-mounted cam operation. The device has 8 cam operators which can operate independently and which have variable higher (lobes) and lower (valleys) segments, and it has 8 control circuits with 10A Snap Action Contact with AC and DC contact ratings. The 803-F812TRH also comes with 150 RPM rotating shaft that moves the cam as it rotates, and it has a contact-mounted cam roller assembly. When the shaft rotates, the cam rotates, and when the cam lobes push up against the cam roller, the circuit is activated, and it is deactivated when the cam valleys move past the cam roller. It has a dwell time which directly depends on the size of the switch’s cam lobes. The maximum dwell time is when the cam lobes are offset, and the minimum dwell time is when they align.

The 803-F812TRH has a timing measured in a degree which determines when the rotating cam activates the circuit, and which is determined by the position of the cam on the shaft, with reference to the Keyway position, and this timing has a total range of 12 to 348 degrees. The switch has external timing and dwell settings that can be adjusted with a screwdriver while the machine is still moving, and it has adjustable cam options, with all available cams substituted for adjustments. It also has a right-hand shaft extension modification, unlike the standard left shaft extension for Style F series, and it is protected by a NEMA Type 4, and 13 oil and water resistant industrial enclosure. The 803-F812TRH’s operating temperature range is -22 to 150 degrees Fahrenheit, without impeding contact control performance, and its storage temperature range is -22 to 200 degrees Fahrenheit. It has a net weight of 6.4 kilograms (14 pounds), with dimensions of 177.8 x 82.6 x 312.7 millimeters (7 x 3.25 x 12.31 inches), and it is CE, CSA, and UL-certified.