In mush wound motors, non-rotor limited designs, thermistors can provide locked rotor protection. Due to their small size and heat sink construction, they have fast response times. Like thermostats, thermistors have a tamper proof pre-set switch point, with a reset only after the motor cools down. Thermistors have several advantages over RTD's, thermocouples and thermostats. We will bring all six (6) leads out unless specified otherwise. Each thermistor has one pre-set, non-adjustable switch point. Thermistors are available with different trip temperatures. The thermistor trip temperature determines the temperature at which the thermistor resistance rises to a very high value, thus tripping the controller. The control module is generally an externally excited solid state device that senses the thermistor resistance and switches contacts when the thermistor input resistance rises above a set resistance value. MOTORS ® brand product lines.Ī control module must be used with the thermistors. PTC type thermistors are supplied on U.S. The negative temperature coefficient (NTC) type thermistor has a resistance that decreases with increasing temperature. The PTC thermistor has a sharp rise in resistance when the temperature reaches the 'knee', or switching point. The positive temperature coefficient (PTC) type has a resistance that increases with increasing temperature. There are two general types of Thermistors. Each specific thermistor has its own unique resistance vs.temperature characteristic.

A thermistor is a non-linear resistance temperature detector, made from semi-conductor material.

Motor winding