Which of the following is not classified as a control device?

The correct choice is the fan motor, as it is primarily an actuator rather than a control device. A fan motor is responsible for converting electrical energy into mechanical energy to move air, which means its primary function is to perform a physical action in response to the commands of a control device.

Control devices, on the other hand, are components that manage or regulate the operation of a system based on specific parameters. For instance, a switch is used to open or close an electrical circuit, a thermostat monitors temperature to maintain set conditions, and a relay acts as an electrically operated switch that can control a larger power load based on a lower power signal. Each of these devices interacts with the broader system to regulate its functions, while a fan motor does not have a regulatory role and is not involved in the control process.