The Allen-Bradley 803-A12W is a rotating cam limit switch that has 12 circuits, and which has been factory-modified to include an external adjustment sprocket that works with chain drive sprockets. This allows the user to change the relative position between the driving mechanism and the shaft. The external sprocket’s pitch diameter measures 0.38 inches and has 48 teeth present. The entire 803-A12W switch has an approximate weight of 20.4 kg or 45 lbs and it has a Type 1 enclosure. The user can mount this switch on any plane. The 803-A12W switch is capable of rotating in either a clockwise or a counterclockwise direction and it features an internal dwell feature and timing adjustments that can only be modified when the device is powered off and at a standstill. Also present on the 803-A12W switch is a spring-loaded cam-roller assembly that is mounted on the contact base.

With a long life expectancy, this switch is good for heavy-duty applications, such as applications in machines that have repetitive operation cycles and applications where the shaft rotation is correlated with the motion. The 803-A12W switch is a Style A switch and like other switches of the same style, it has a maximum shaft speed of 150 RPM, 25 Amp. N. C. (normally closed) double break contacts, a cam duration range of a minimum of 14 degrees to a maximum of 346 degrees, and a standard left shaft extension. The operating temperature of this switch is from -22 to 151 degree Fahrenheit, while its non-operating temperature is from -22 to 199 degree Fahrenheit. It also has typical shaft torques of 0.5 pounds on an inch with the cam roller in the valley, 3 pounds on an inch when the cam roller rides on the lobe, and 7 lb-in when the cam roller rides up the cam ramp.