114
Check first when you have a trouble
4.6.7 Acceleration/deceleration is not smooth
4.6.8 Speed varies during operation
When the slip compensation is selected, the output frequency varies between 0 and 2Hz as with load fluctuates. This is a
normal operation and not a fault.
Check
points
Possible Cause Countermeasures
Refer
to
page
Parameter
Setting
Acceleration/deceleration time is too short. Increase acceleration/deceleration time. 46
Torque boost (Pr. 0, Pr. 46) setting is improper under V/F
control, so the stall prevention function is activated.
Increase/decrease Pr. 0 Torque boost setting value by
0.5% increments to the setting.
44
The base frequency does not match the motor
characteristics.
For V/F control, set Pr. 3 Base frequency and Pr. 47 Second
V/F (base frequency).
43
For General-purpose magnetic flux vector control, set Pr.
84 Rated motor frequency.
50
Stall prevention function is activated due to a heavy
load.
Reduce the load weight. —
Set Pr. 22 Stall prevention operation level higher according
to the load. (Setting Pr. 22 too large may result in
frequent overcurrent trip (E.OC).)
77
Check the capacities of the inverter and the motor. —
Regeneration avoidance operation is performed
If the frequency becomes unstable during regeneration
avoidance operation, decrease the setting of Pr. 886
Regeneration avoidance voltage gain.
94
Check
points
Possible Cause Countermeasures
Refer
to
page
Input
signal
Multi-speed command signal is chattering. Take countermeasures to suppress chattering. —
Load Load varies during an operation. Select General-purpose magnetic flux vector control. 48
Input
signal
Frequency setting signal is varying. Check the frequency setting signal. —
The frequency setting signal is affected by EMI.
Set filter to the analog input terminal using Pr. 74 Input
filter time constant.
82
Take countermeasures against EMI, such as using
shielded wires for input signal lines.
Malfunction is occurring due to the undesirable current
generated when the transistor output unit is connected.
Use terminal PC (terminal SD when source logic) as a
common terminal to prevent a malfunction caused by
undesirable current.
18
Parameter
Setting
Pr. 80 Motor capacity setting is improper for the
capacities of the inverter and the motor for General-
purpose magnetic flux vector control.
Check the Pr. 80 Motor capacity setting. 48
Fluctuation of power supply voltage is too large.
Change the Pr. 19 Base frequency voltage setting (about
3%) under V/F control.
75
Hunting occurs by the generated vibration, for example,
when structural rigidity at load side is insufficient.
Disable automatic control functions, such as energy
saving operation, fast-response current limit function,
regeneration avoidance function, General-purpose
magnetic flux vector control, and stall prevention.
Adjust so that the control gain decreases and the level of
safety increases.
—
Change Pr. 72 PWM frequency selection setting. 82
Others
Wiring length exceeds 30m when General-purpose
magnetic flux vector control is performed.
Perform offline auto tuning. 50
Wiring length is too long for V/F control, and a voltage
drop occurs.
Adjust Pr. 0 Torque boost by increasing with 0.5%
increments for low-speed operation.
44
Change to General-purpose magnetic flux vector
control.
48
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