Stall prevention STP

What does E.OLT mean?

The inverter output is shut off if stall prevention operation causes the output frequency to drop to 0.5 Hz for 3 seconds, or if torque limit operation causes frequency to drop to Pr.865 and output torque exceeds Pr.874 for 3 seconds in speed control. This protective fault indicates severe motor overload or an issue with stall prevention settings.

• Excessive mechanical load causing the motor to operate in a stalled condition or at very low speeds.
• Motor is undersized for the application, leading to continuous stall prevention activation.
• Pr.22 (Stall prevention operation level) or Pr.865 (Stall prevention frequency lower limit) are set too aggressively for transient loads.
• Mechanical binding or obstruction in the driven equipment preventing free rotation.
• Insufficient motor torque boost (e.g., Pr.0, Pr.18) at low frequencies, leading to poor motor performance and stall.

Click steps to track your progress.

1. 1

   Monitor motor current (e.g., Pr.205 Output current) and torque output (if available) during operation to confirm actual load.

2. 2

   Inspect the mechanical system for any binding, friction, or obstruction that could be overloading the motor.

3. 3

   Increase Pr.22 (Stall prevention operation level) slightly or extend the time delay for stall detection if transient overloads are common.

4. 4

   Verify motor sizing against the application's maximum and continuous load requirements, potentially recommending a larger motor.

5. 5

   Adjust Pr.865 (Stall prevention frequency lower limit) to a slightly lower value if the application legitimately operates below 0.5 Hz under specific conditions.