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11.2  Troubleshooting During Trial Run
This section provides solutions to oscillation, poor torque or speed response, or other problems that 
occur while performing a trial run.
 
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Drive in Open-loop Vector Control (F0-01 = 0: Default value)
The AC drive implements control of the motor speed and torque without an encoder for speed 
feedback. In this control mode, motor auto-tuning is required to obtain the motor related 
parameters.
Problem Solutions
Overload or 
overcurrent detected 
during motor start
1. Set motor parameters F1-01 to F1-05 according to motor nameplate.
2. Select a proper motor auto-tuning mode by setting F1-37 and perform 
motor auto-tuning. If possible, select dynamic auto-tuning (F1-37 = 2).
Poor torque or speed 
response and motor 
oscillation at speeds 
below 5 Hz
1. If motor torque and speed response are too slow, increase the setting 
of F2-00 (speed loop proportional gain 1) by 10 gradually or decrease 
the setting of F2-01 (speed loop integral time 1) by 0.05 gradually.
2. If motor oscillation occurs, decrease the setting of F2-00 and F2-01.
Poor torque or speed 
response and motor 
oscillation at speeds 
above 5 Hz
1. If motor torque and speed response are too slow, increase the setting 
of F2-03 (speed loop proportional gain 2) by 10 gradually or decrease 
the setting of F2-04 (speed loop integral time 4) by 0.05 gradually.
2. If motor oscillation occurs, decrease the setting of F2-03 and F2-04.
Low speed accuracy If speed error when motor runs with load is large, increase the setting of 
F2-06 (vector control slip compensation gain) by 10% gradually.
Obvious speed 
uctuation
If motor speed uctuation is large, increase the setting of F2-07 (SVC 
torque lter time) by 0.001s gradually.
Too loud motor noise Increase the setting of F0-15 (carrier frequency) by 1.0 kHz gradually.
Note that increase in carrier frequency will result in an increase in the 
leakage current of the motor.
Insufcient motor 
torque
Check whether torque upper limit is small. If yes, please:
 ● Increase the setting of F2-10 (digital setting of torque upper limit in 
speed control mode) in the speed control mode.
 ● Increase the torque reference (A0-03) in the torque control mode.
 
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Drive in Feedback Vector Control (F0-01 = 1)
It is applicable to the application with an encoder for speed feedback. In this mode, you need 
to set the encoder pulses per revolution (F1-27), the encoder type (F1-28) and the encoder 
direction (F1-30) correctly.
Problem Solutions
Overload or 
overcurrent fault 
detected during motor 
start
Set F1-27, F1-28 and F1-30 correctly. 
Overload or 
overcurrent detected 
during motor running
1. Set motor parameters F1-01 to F1-05 according to the motor 
nameplate.
2. Select a proper motor auto-tuning mode by setting F1-37 and perform 
motor auto-tuning. If possible, select dynamic auto-tuning (F1-37 = 2).