RPM Alert Basic Troubleshooting
Verify the sheaves match the part numbers on the General Arrangement drawing.
Verify the belt cross section is correct for the sheaves installed.
Are belts properly tensioned? Any sign of slipping? Adjust if required.
Is a variable frequency drive (VFD) installed on the machine? Verify the operating frequency is set correctly.
Understanding RPM Alerts
Vibratory equipment that uses reaction springs (natural frequency design) is engineered to operate at a specific eccentric shaft or vibratory motor RPM. Even a small change in operating speed can significantly affect the operating stroke. On natural frequency equipment, a variation of as little as 10 RPM may be enough to impact performance.
RPM Changes
If no other changes have been made, reducing the operating RPM decreases the operating stroke, while increasing the RPM increases the stroke. Some RPM changes can be accommodated by re-tuning the machine (adding or removing springs). Always consult ACTION before making speed changes to ensure the equipment remains within its design limits.
RPM can be checked and monitored with ACTION’s VIBRA-SYNC™ System. Learn more about VIBRA-SYNC™
Belt/Sheave Wear
One common cause of RPM loss is wear on drive belts and sheaves. Over time, worn V-grooves allow the belts to ride lower in the sheaves, reducing the operating RPM and stroke. Check the RPM with a tachometer or strobe light, and replace worn belts and sheaves if necessary—especially on older equipment.
Replacement Parts
RPM changes can also result from incorrect replacement components. Using belts with the wrong cross-section or installing a sheave with an incorrect pitch diameter can alter the operating speed. Always verify replacement part numbers and pitch diameters against the General Arrangement drawing before installation.
VFDs/Soft Starts
ACTION Vibratory equipment is designed to be operated with a motor contractor at mains voltage and frequency indicated on the General Arrangement drawing. Use of a soft start or VFD is not recommended.
A soft start can cause the machine to fail to start and slip the drive timing requiring maintenance. A VFD can cause severe over or under stroke with a minor frequency setting change. Never use a soft start with ACTION Equipment and contact ACTION before using a VFD with vibratory equipment.
