7. Electromagnetic control systems.

An electromagnetic control system activates the various parts of a machine, at the right moment and for the right amount of time, ensuring that the machine functions properly.

7.1. Cam switch controller.
The device on the side of the pulley in the picture above is called a cam. The shape of this device allows us to control the moment and duration of an activity, such us the running of a motor or the illumination of a light bulb.

7.2. Limit swtiches.
The picture below shows an electrical control system for a water tank. The battery provides power for the pump, which moves water from the lower tank to the upper tank. is full, a limit switch turns off the pump.

The switch is activated when the float rises to a certain level. When the water level goes down, the switch returns to its original position and the pump turns on again. There are two types of limit switch: