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Check first when you have a trouble
5
PROTECTIVE FUNCTIONS
5.5.8 Speed varies during operation
When Advanced magnetic flux vector control, Real sensorless vector control, vector control or encoder feedback control is
exercised, the output frequency varies with load fluctuation between 0 and 2Hz. This is a normal operation and is not a fault.
Check
points
Possible Cause Countermeasures
Refer
to
page
Load Load varies during an operation.
Select Advanced magnetic flux vector control, Real
sensorless vector control, vector control, or encoder
feedback control.
92, 381
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, Pr. 822 Speed setting filter 1.
292
Take countermeasures against EMI, such as using
shielded wires for input signal lines.
54
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.
29
Multi-speed command signal is chattering. Take countermeasures to suppress chattering. —
Feedback signal from the encoder is affected by EMI.
Place the encoder cable far from the EMI source such
as main circuit and power supply voltage.
Earth (ground) the shield of the encoder cable to the
enclosure using a metal P-clip or U-clip.
36
Parameter
Setting
Fluctuation of power supply voltage is too large.
Change the Pr. 19 Base frequency voltage setting (about
3%) under V/F control.
159
Pr.80 Motor capacity and Pr.81 Number of motor poles are
not appropriate for the motor capacity under Advanced
magnetic flux vector control, Real sensorless vector
control, or vector control.
Check the settings of Pr.80 Motor capacity and Pr.81
Number of motor poles.
92
Wiring length exceeds 30m when Advanced magnetic
flux vector control, Real sensorless vector control, or
vector control is selected.
Perform offline auto tuning. 189
Wiring length is too long for V/F control, and the a
voltage drop occurs.
Adjust the Pr. 0 Torque boost setting by increasing with
0.5% increments for the low-speed operation.
146
Change the control method to Advanced magnetic flux
vector control or Real sensorless vector control.
92
Hunting occurs by the generated vibration, for example,
when structural rigidity at load side is insufficient.
Disable automatic control functions, such as the energy
saving operation, the fast-response current limit function,
the torque limit, the regeneration avoidance function,
Advanced magnetic flux vector control, Real sensorless
vector control, vector control, encoder feedback control,
droop control, the stall prevention, online auto tuning, the
notch filter, and orientation control.
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.
284