Mitsubishi Electronics FR-F700-NA ユーザーズマニュアル
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
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.
filter time constant.
Take countermeasures against EMI, such as using
shielded wires for input signal lines.
shielded wires for input signal lines.
Malfunction is occurring due to the undesirable current
generated when the transistor output unit is connected.
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.
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.
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.
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.
drop occurs.
Adjust Pr. 0 Torque boost by increasing with 0.5%
increments for low-speed operation.
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.
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.
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
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.
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.
correspond.
Check Pr. 79, Pr. 338, Pr. 339, Pr. 550, Pr. 551, and select
an operation mode suitable for the purpose.
an operation mode suitable for the purpose.