- 296 -
Problem Solutions
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).
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) by1.0 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.
 
■
Drive in V/F Control (F0-01 = 2)
It is applicable to application without an encoder for speed feedback. You need to set rated 
motor voltage (F1-02) and rated motor frequency (F1-04) correctly.
Problem Solutions
Motor oscillation 
during running
Increase the setting of F3-11 (V/F oscillation suppression gain) by 10 
gradually. The permissible maximum setting here is 100.
Overcurrent during 
start
Decrease the setting of F3-01 (torque boost) by 0.5% gradually.
Very large current 
during running
1. Set rated motor voltage (F1-02) and rated motor frequency (F1-04) 
correctly.
2. Decrease the setting of F3-01 (torque boost) by 0.5% 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.
Overvoltage detected 
when heavy load is 
suddenly removed or 
during deceleration
1. Ensure that F3-23 (voltage limit selection) is set to 1 (enabled). 
Increase the setting of F3-24/F3-25 (frequency gain/voltage gain for 
voltage limit) by 10 gradually. The permissible maximum setting here is 
100. The default value of F3-22 is 30. 
2. Decrease the setting of F3-22 (voltage limit) by 10 V gradually. The 
permissible minimum setting here is 700 V. The default value of F3-20 
is 770 V.
Overcurrent detected 
when heavy load is 
suddenly added or 
during acceleration
1. Increase the setting of F3-20 (current limit gain) by 10 gradually. The 
permissible maximum setting here is 100. The default value of F3-22 is 
20.
2. Decrease the setting of F3-18 (current limit level) by 10% gradually. 
The permissible minimum setting here is 50%. The default value of    
F3-18 is 150%.