MTR01 relay controls motor winding temperature. It is based on the measurement of PTC thermistor which is built in electrical motor. Device also controls short-circuit or probe disconnection. The relay has one output double-throw contact 8 A.

MTR01V24 type is designed for the supply voltage of 24 V. Other parameters are the same.

Device functions

MTR01 function

If the motor temperature is under maximum limit (PTC = 3,3 kΩ), green LED is ON and contact 15-16 is closed. As soon as the motor winding is overheated (PTC > 3,3 kΩ), red LED turns ON and contact 1518 switches ON. Switch OFF operation will occur after the motor winding temperature drops down (PTC 1,8 kΩ) and button RESET has been pressed. This feature protects motor against spontaneous start and it is possible to be disabled by cross connection of terminals T1, R1 (AUTORESET). There is also possibility to use terminals T1,R1 for external reset. If the PTC input is short-circuited, alarm appears and terminal 15-18 will switch ON.

thermistor monitoring relay MTR01

Main features

  • Probe short circuit monitoring
  • Probe disconnection monitoring
  • High sensitivity of resistance measuring
  • Supply voltage 230 VAC or 24 VAC/DC
  • DFT (Discrete Fourier Transformation)
  • Digital optical operation status signalisation