These non-reversing NEMA motor starters with thermal overloads have enclosures that protect their internal components from impacts, debris, and dust. Non-reversing motor starters connect and disconnect power to motors and other high-current equipment and machinery in a single direction. Thermal overloads, also known as heaters, prompt motor starters to break electrical connections with downstream equipment once a set temperature is reached to protect connected loads from overheating and causing damage. They contain either bimetallic strips or melting alloy solder materials. When the current exceeds a predetermined threshold and temperatures rise, the material bends or liquefies, causing the thermal unit to break the circuit and cause the motor starter to break its power contacts. As the materials cool down, they will return to their normally closed position and the circuit can be reset automatically or manually.