Motor Pull Out or Step Out Detection

What does STo mean?

The motor has exceeded its pull-out torque, resulting in a motor pull-out or step-out condition. This can be caused by an incorrect motor code for PM motors, an excessively heavy load, high load inertia, or acceleration/deceleration times that are too short for the system's dynamics.

• Excessive mechanical load exceeding the motor's rated torque capacity.
• Incorrect motor rated current (P1-02) or motor pole count (P1-04) parameters for the connected motor.
• Insufficient motor sizing for the application, especially with high load inertia.
• Incorrect motor code (P1-06) selected for permanent magnet (PM) motors.
• Damaged or misaligned encoder providing inaccurate speed/position feedback (if used for control).

Click steps to track your progress.

1. 1

   1. Verify that the motor rated current (P1-02), rated power (P1-01), and rated voltage (P1-03) parameters exactly match the motor nameplate data.

2. 2

   2. Check for mechanical binding, excessive friction, or blockages in the driven equipment.

3. 3

   3. Increase the torque limit parameters (C1-01 for forward, C1-02 for reverse) if mechanically permissible and within motor limits.

4. 4

   4. Confirm the correct motor type is selected in parameter P1-06 (e.g., Induction, SPMS, IPMS).

5. 5

   5. Review acceleration/deceleration times (C1-03, C1-04) and lengthen them if high inertia is present, reducing peak torque demand.

6. 6

   6. Monitor motor current and actual speed during operation to observe precisely when the pull-out condition occurs relative to load.