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Check first when you have a trouble
6.5.8
Speed varies during operation
When Advanced magnetic flux vector control or the slip compensation is selected, the output frequency varies between 0 and
2Hz as load fluctuates. This is a normal operation and not a fault.
Check
points
Load
Load varies during an operation.
Input
Frequency setting signal is varying.
signal
Pr. 80 Motor capacity and Pr. 81 Number of motor poles
settings are improper for the capacities of the inverter
and the motor for Advanced magnetic flux vector control
or General-purpose magnetic flux vector control.
Fluctuation of power supply voltage is too large.
Parameter
setting
Hunting occurs by the generated vibration, for example,
when structural rigidity at load side is insufficient.
Wiring length exceeds 30m when Advanced magnetic
flux vector control or General-purpose magnetic flux
vector control is performed.
Others
Wiring length is too long for V/F control, and a voltage
drop occurs.
6.5.9
Operation mode is not changed properly
Check
points
Input
Start signal (STF or STR) is ON.
signal
Pr. 79 setting is improper.
Parameter
setting
Pr. 542 Communication station number (CC-Link) is set
incorrectly. (Unmatched with the program, overlapping
station number, out-of-range station number, etc.)
The CC-Link dedicated cable is not installed correctly.
(having contact faults and breaks, etc.)
The operation mode switching program is not designed
Others
correctly.
The operation mode switching program has not been
executed.
248
Possible Cause
Possible Cause
Countermeasures
Select Advanced magnetic flux vector control or
General-purpose magnetic flux vector control.
Check the frequency setting signal.
Check the Pr. 80 Motor capacity and Pr. 81 Number of
motor poles settings.
Change the Pr. 19 Base frequency voltage setting (about
3%) under V/F control.
Disable automatic control functions, such as energy
saving operation, fast-response current limit function,
regeneration avoidance function, Advanced magnetic
flux vector control, General-purpose magnetic flux
vector control, and stall prevention.
During the PID control, set smaller values to Pr.129 PID
proportional band and Pr.130 PID integral time.
Lower the control gain, and adjust to increase the
stability.
Change Pr. 72 PWM frequency selection setting.
Perform offline auto tuning.
Adjust Pr. 0 Torque boost by increasing with 0.5%
increments for low-speed operation.
Change to Advanced magnetic flux vector control or
General-purpose magnetic flux vector control.
Countermeasures
Check that the STF and STR signals are OFF.
When either is ON, the operation mode cannot be
changed.
When Pr. 79 Operation mode selection setting is "0" (initial
value), the inverter is placed in the Network operation
mode at input power ON. To switch to the PU operation
mode, press
on the operation panel. Switchover
mode is selected with the setting value "6".
Set Pr. 542 Communication station number (CC-Link)
correctly.
Install the CC-Link dedicated cable correctly.
Design the operation mode switching program correctly.
Execute the operation mode switching program.
Refer
to
page
114
—
114
126
—
192
146
113
114
Refer
to
page
103
103
105
52
69
69
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