KEB COMBIVERT F5 Reference Manual page 297

Problem
Motor does not go the correct
speed or cannot reach high
speed.
Overshoot into floor
Cannot lift full load
Diagnostics and Troubleshooting
Cause/Solution/Troubleshoot
Check whether the Command Speed and Encoder Speed match
(Home Screen or Diagnostics Screen #1). .
Verify whether the Motor (Encoder) Speed is tracking the Command
Speed.
Check which Active Speed and/or Active Profile is selected.
Check the speed setting for the corresponding Active Speed/Active
Profile selected.
Check whether the Machine Data parameters (LN) are set correct.
Check whether the (Voltage) Modulation Grade is reaching 100%. Refer
to Voltage Modulation Grade limit reached for further troubleshooting.
Check whether the Maximum Torque Limit or Inverter Peak Current
limit are being reached.
Check if the speed control gains (KP Proportional, KI Integral Offset)
are set too low.
Check the motor current, whether the Maximum Torque Limit or
Inverter Peak Current limit are being reached.
Check whether the Motor (Encoder) Speed is tracking the Command
Speed.
Check if the speed control gains (KP Proportional, KI Integral Offset)
are set too low. Raise as needed.
Check the motor current, whether the Maximum Torque Limit or
Inverter Peak Current limit are being reached. Refer to Motor Draws
High Current for additional troubleshooting.
Check if the speed control gains (KP Proportional, KI Integral Offset)
are set too low.
For open loop induction motors, the Low Speed Torque Boost may
need to be increased or decreased if reaching the Maximum Torque
Limit or Inverter Peak Current.
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