351
Check first when you have a trouble
5
5.5.8
Speed varies during operation
5.5.9
Operation mode is not changed properly
Check
points
Possible Cause
Countermeasures
Refer
to
page
Load
Load varies during an operation. (V/F Control)
Select Simple magnetic flux vector control
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
.
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.
Multi-speed command signal is chattering.
Take countermeasures to suppress chattering.
—
Parameter
Setting
Fluctuation of power supply voltage is too large.
Change the
Pr. 19 Base frequency voltage
setting (about
3%) under V/F control.
Pr. 80 Motor capacity
setting is improper for the
capacities of the inverter and the motor for Simple
magnetic flux vector control.
Check the
Pr. 80 Motor capacity
setting.
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.
Change to Simple magnetic flux vector control.
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, Simple magnetic flux
vector control and stall prevention.
For PID control, set smaller values to
Pr.129 PID
proportional band
and
Pr.130 PID integral time
.
Adjust so that the control gain decreases and the level of
safety increases.
—
Change
Pr. 72 PWM frequency selection
setting.
Check
points
Possible Cause
Countermeasures
Refer
to
page
Input
signal
Start signal (STF or STR) is ON.
Check that the STF and STR signals are OFF.
When either is ON, the operation mode cannot be
changed.
Parameter
Setting
Pr. 79
setting is improper.
When
Pr. 79 Operation mode selection
setting is "0" (initial
value), the inverter is placed in the External operation
mode at input power ON. To switch to the PU operation
mode, press
on the operation panel (press
when the parameter unit (FR-PU04/FR-PU07) is used) .
At other settings (1 to 4, 6, 7), the operation mode is
limited accordingly.
Operation mode and a writing device do not
correspond.
Check
Pr. 79, Pr. 338, Pr. 339, Pr. 550, Pr. 551,
and select
an operation mode suitable for the purpose.
Summary of Contents for 700 Series
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