Measuring Transducer for Motor Protection TMU300 for 3 x Pt100

Measuring Transducer for motor protection with sealed-in elekctronics, for 3 x Pt 100,  analog output

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Part number

Product description


Transducers for motor protection TMU300 are transducers for 1-3 sensors Pt100 (RTD). A new, current-saving measuringsystem makes it possible to evaluate 3 sensors with a transducer that is supplied by a loop 4-20 mA. 

This design is protected. The sensors Pt100 are connected in 2-wire-technique. The output signal is a current 4-20 mA. The value of the output current corresponds with the temperature of the hottest sensor.


Recording of temperatures at e.g. motors, generators, transformers or compressors and forward them to relais or controls for evaluation.

In difference to PTC with sensors Pt100 a adjustable switching temperature can be realized. The temperature protection can be adapted to the requirements at any time. 

Optimal operation and longer life by intelligent management possible. E.g. no start at high motor temperatures. 

The cast-resign sealed electronics can be used at temperatures up to 85 °C and thus be placed near the sensors, e.g. in the terminal box of a motor. This reduces influence of EMC and line resistance. The signal 4-20 mA can be transmitted over long distances.


  • connection of 1-3 sensors Pt 100 in 2-wire-technique
  • measuring range 0...200 °C
  • automatic selection of warmest sensor
  • I < 3,5 mA at short circuit in any sensor
  • I > 25 mA at interruption in any sensor
  • analog output 4-20 mA
  • rated ambient temperature up to 85 °C
  • no supply voltage required (supplied by 4-20 mA loop)
  • with sealed-in electronics

Technical Data



1 - 3 x Pt 100 DIN 43 760/IEC 751 without compensation of line resistance



Current output


DC 4...20 mA


Voltage loop


DC 12...32 V




class 2,5


Temperature coefficient


0,025 %/°K


Reference conditions


IEC 770, Tu = 23 °C ± 5 °C, Us = DC 24 V ± 1 V


adm. operating temperature


-20...+85 °C



Dimensions (W x H x D)


Design 420 with terminals 60 x 55 x 32 mm




Screw mounting 2 x M4


Protection housing / terminals


IP 40 / IP 20




approx. 70 g