TF/TH sensor tripped

What does F-31 mean?

The motor's TF/TH thermal sensor has tripped, indicating the motor is overheating, or there's an issue with the sensor connection. Possible causes include a disconnected, incorrectly wired sensor, or an interrupted connection between the MOVITRAC® B and the sensor. Continued operation with an overheated motor risks severe winding damage.

• Motor internal thermal sensor (e.g., PTC type) resistance value has exceeded its trip threshold (e.g., >1.65kOhm for PTC) due to actual motor overheating.
• Thermal sensor wiring (terminals T1/T2) is disconnected, leading to an open circuit and a default trip condition.
• Short circuit in the thermal sensor wiring or within the sensor itself, causing an invalid resistance reading.
• Incorrect thermal sensor type (e.g., NTC instead of PTC) wired to the drive's thermal input, resulting in an erroneous reading.
• Motor cooling fan failure or blocked ventilation fins, leading to insufficient heat dissipation and actual motor overheating.

Click steps to track your progress.

1. 1

   Disconnect power to the motor and drive. Measure the resistance across the motor's thermal sensor terminals (e.g., T1 and T2 on the motor terminal block).

2. 2

   Compare the measured resistance value with the motor's specified thermal sensor type and trip/reset values (e.g., PTC: <250Ohm normal, >1.65kOhm trip).

3. 3

   If the resistance is outside the normal range, inspect the wiring from the motor's sensor terminals to the drive's thermal input terminals (e.g., X1/T1 and X1/T2) for breaks or shorts.

4. 4

   Verify the motor's cooling fan operation and ensure the motor's cooling fins are free from dust and debris, checking for airflow blockage.

5. 5

   Check the motor's current draw (Parameter P1-07 for actual motor current) and compare it against the motor's rated current (from nameplate) to confirm no sustained overload.

6. 6

   If the sensor wiring and motor cooling are confirmed good and the motor is not overloaded, replace the motor's internal thermal sensor (if accessible) or the motor itself if the sensor is integrated.