What does a thermal overload protection device primarily sense?

A thermal overload protection device is designed to prevent overheating in electrical systems by sensing the amount of heat generated due to current flow. This heat builds up when the current exceeds the rated capacity of the system, indicating that the circuit is overloaded. When the device detects excessive heat, it activates to disconnect or trip the circuit, thereby preventing damage to the electrical components or the risk of fire. This operation is crucial in maintaining safe and reliable electrical performance.

While voltage drop, physical motion of a switch, and resistance are important parameters in electrical systems, they do not specifically pertain to the core function of a thermal overload protection device, which is focused solely on monitoring heat generation and ensuring that the system does not operate beyond its thermal limits.