The 803-F712T Rotating Cam Limit Switch with Internal Adjustable Cam option is a Style “F” heavy-duty circuit control rotating switch by Allen-Bradley that is used with machinery with repetitive cycles of operation, in applications where the machine motion directly correlates with the switch’s shaft rotation. The device uses a shaft-mounted cam which actuates contact as the shaft rotates, and it is suitable for heavy-duty industrial applications with long operation lives. The 803-F712T has 7 circuits with a snap-action contact block, and 7 independently-operated cam assemblies, with adjustable cam lobes and valleys (the upper and lower cam segments), and it comes with a spring-loaded cam roller. The 803-F712T has a rotating shaft with a 150 RPM base speed, and a keyway (shaft slot) which connects the shaft to the machines, and the circuit is activated by the cam when the cam lobe pushes against the cam roller while the shaft rotates. The snap-action contact has AC contact ratings of 15A/1.5A MAKE/BREAK current at 480 Volts AC, and a DC rating of 0.1 at 550 to 600 Volts DC, with a carrying current of 10A.

The 803-F712T has a dwell time which corresponds to the amount of time for which the cam lobe activates the circuit, and it is determined by the length of the lobe and a timing when the rotating cam activates the circuit, and it is also determined by the position of the cam with reference to the keyway’s top dead center (TDC). The 803-F712T, like all style “F” switches, has external dwell and timing adjustments, which can be done by using screwdriver while the machine is in motion, and the switch also comes with a standard left shaft extension. It has internally adjustable cams, and all the cams on the device have been substituted with internally adjustable cams. The 803-F712T has an operating temperature range of -30 to 66 degrees Celsius (-22 to 150 degrees Fahrenheit), with a non-operating and storage temperature range of -30 to 93 degrees Celsius (-22 to 200 degrees Fahrenheit), and it is enclosed with a NEMA Type 4, and 13 watertight and dust-tight industrial enclosure. It weighs approximately 6.4 kilograms (14 pounds), with overall dimensions of 177.8 x 82.6 x 312.7 millimeters (7 x 3.25 x 12.31 inches), and is UL, CSA, and CE-certified.