Wiring - Temperature Sensors

Temperature Sensors

The LTMR controller has two terminals dedicated to motor temperature sensing protection: T1 and T2. These terminals return the temperature value measured by resistance temperature detectors (RTDs).

One of the following types of motor temperature sensor can be used:

PTC Binary
PT100
PTC Analog
NTC Analog

For more information on temperature sensors, refer to the TeSys T LTMR Motor Management Controller User Guide.

Temperature Sensor Wiring

The following table shows the maximum wire lengths for temperature sensor elements:

Wire Size	0.5 mm² (AWG 20)	0.75 mm² (AWG 18)	1.5 mm² (AWG 16)	2.5 mm² (AWG 14)
Maximum Wire Length	220 m (656 ft)	300 m (985 ft)	400 m (1312 ft)	600 m (1970 ft)

Use unshielded twisted pair cable to connect the controller to the temperature sensor.

For the controller to accurately measure the resistance of the temperature-sensing element, you must measure the resistance of the twisted-pair and add it to the desired resistance for protection. This compensates for the lead resistance.

The following diagram shows the wiring of the LTMR controller and the temperature sensor of a single-phase motor:

For more information about wiring, see Wiring Generalities.