I was reading basic electricity by valkenburgh and on page 5_68, he talks about overload srelay. The part i dont understand is when he says " in many circuits you will see overload relay contacts in series with the line. These contacts are normally closed, but of the temperature of the device becomes excessive, the thermal relay will close causing the overload relay to become energized and opening the line." The part i dont understand is" the thermal relay will close, causing the overload relay to become energized and opening. The line." It seems as if the thermal relay and overload relay are two separate relays, with the thermal relay closing to provide a switch to activate the elecyromechanical relay to open the overload contacts.