From production practice, a loose scoop head is the main cause of this periodic, intermittent current increase. It’s also important to check if there are steel balls or other iron objects obstructing the scoop’s rotation at the bottom.

If the current continues to rise and does not return to the rated current, it may be due to excessive mill load or low voltage. Excessive mill load is caused by a large feed rate; the feed rate should be adjusted, and the mill should be stopped. If the continuous current increase is caused by low voltage, it’s purely an external power supply issue. A proactive approach is to frequently observe for significant changes in current and motor temperature rise.