This is the control circuit for a magnetic motor starter. It displays the Start and Stop buttons along with a seal in contact and an overload contact. When you press the Start button, the relay will pull in the seal in contact and the three terminals (terminals not shown due to lack in detail in the app) and the seal in contact keeps the relay going even after you let go of the button. Their are 2 ways to stop the circuit, and that is with the Stop button or if the overload contact is opened. Normally heat would open the overload contact to avoid overheating the motor.
