A PTC thermistor (Positive Temperature Coefficient) is a temperature-sensitive resistor used for thermal protection in electric motors. Unlike RTD sensors, it does not provide continuous temperature measurement but acts as a temperature switch.
When the predefined threshold temperature is reached, the resistance of the PTC thermistor suddenly increases, triggering the motor protection relays and causing the motor to shut down. It is widely used for fast and reliable overheating protection of motor windings.
