SINAMICS G120 A07910: Motor overtemperature alarm, what to check?
I'm getting an A07910 alarm on my SINAMICS G120 drive. The motor is running a constant speed application. What should I check first to troubleshoot this motor overtemperature alarm?
The SINAMICS G120 A07910 alarm indicates that the motor's measured temperature (KTY sensor) or thermal model has exceeded the alarm threshold (p0604), or a PTC/bimetal contact has responded. This is an alarm, not a fault, meaning the drive continues to operate. The drive's response to this alarm, such as current reduction or a subsequent F07011 fault, is determined by parameter p0610.
Likely causes and checks
1Motor overloaded
- Points to it
- Sustained high current can cause the motor to overheat, especially during constant speed operation under heavy load.
- Check
- Verify the motor load and current against its rating plate specifications. Look for signs of the alarm appearing after prolonged high current draw.
2Motor cooling impaired or ambient temperature too high
- Points to it
- Ineffective cooling or a hot environment prevents the motor from dissipating heat, leading to overtemperature. This is common with self-cooled motors running at low speeds.
- Check
- Inspect the motor's cooling fan and air path for any blockages or dirt. Measure the ambient temperature around the motor and ensure it's within acceptable limits.
3Temperature sensor or wiring issue
- Points to it
- A faulty sensor or damaged wiring can send incorrect temperature readings, triggering a false alarm even if the motor is cool. Other sensor-related messages like A07015 or F07016 might also appear.
- Check
- Check the wiring for the KTY84/PTC sensor for continuity and proper connection. Verify the sensor type setting in parameter p0601.
4Incorrect thermal model settings (if no sensor is used)
- Points to it
- If the drive relies on a thermal model instead of a physical sensor, incorrect parameter settings can lead to an alarm without actual motor heating.
- Check
- Review the thermal model temperature parameters p0626 (stator core), p0627 (stator winding), and p0628 (rotor) and ensure they are correctly configured for your motor data.
Next check: After checking for motor overload, cooling issues, and sensor problems, if the alarm persists without actual motor heating, review the thermal model parameters p0626, p0627, and p0628, and ensure they align with the motor's specifications.
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