7.ELECTROMAGNETIC CONTROL SYSTEMS:
An electromagnetic control system activites the various parts of a machine,at the right momento and for the right amount of time,ensuring that the machine funtions 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 as the running of a motor or the illumination of a light bulb.

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

• Normally closed.
• Normally open.