Speed Does Not Accelerate - Mitsubishi Electric FR-F820-00046 Instruction Manual

6.6.12 Speed does not accelerate

Check
point
The start command or frequency command
is chattering.
The wiring length is too long for the analog
Input
frequency command, causing a voltage
signal
(current) drop.
The input signal lines are affected by
external EMI.
Pr.1 Maximum frequency, Pr.2 Minimum
frequency, Pr.18 High speed maximum
frequency, and the calibration parameter
C2 to C7 settings are not appropriate.
The maximum voltage (current) input value
is not set during the External operation.
(Pr.125, Pr.126, Pr.18)
The torque boost (Pr.0, Pr.46) setting is not
appropriate under V/F control, so the stall
prevention function is activated.
The V/F pattern is not appropriate when V/
F control is performed. (Pr.3, Pr.14, Pr.19)
Parameter
setting
Stall prevention function is activated due to
a heavy load.
Auto tuning is not performed under
Advanced magnetic flux vector control.
The setting of pulse train input is not
appropriate.
During PID control, the output frequency is automatically controlled so that the measured value equals the set
point.
6.6.13 Unable to write parameter setting
Check
point
Input Operation is being performed (the STF or
signal STR signal is ON).
Parameter setting was attempted in the
External operation mode.
Parameter write is disabled by the Pr.77
Parameter write selection setting.
The key lock mode is enabled by the
Parameter
Pr.161 Frequency setting/key lock
setting
operation selection setting.
Operation mode and a writing device do
not correspond.
Under PM motor control, setting "25" in
Pr.72 PWM frequency selection was
attempted. Or, setting PM motor control
was attempted while Pr.72 = "25".
592
6. PROTECTIVE FUNCTIONS
6.6 Check first when you have a trouble
Possible cause
Possible cause
Countermeasure
Check if the start command and the frequency command are
correct.
Perform the bias and gain calibration for the analog input.
Take countermeasures against EMI, such as using shielded wires
for input signal lines.
Check the Pr.1 and Pr.2 settings. To operate at 120 Hz or higher,
set Pr.18.
Check the calibration parameter C2 to C7 settings.
Check the settings of Pr.125 Terminal 2 frequency setting gain
frequency and Pr.126 Terminal 4 frequency setting gain
frequency. To operate at 120 Hz or higher, set Pr.18 High speed
maximum frequency.
Increase/decrease the Pr.0 Torque boost setting value by 0.5%
increments so that stall prevention does not occur.
Set the rated frequency of the motor to Pr.3 Base frequency.
Use Pr.19 Base frequency voltage to set the base voltage (for
example, rated motor voltage).
Change the Pr.14 Load pattern selection setting according to the
load characteristic.
Reduce the load weight.
Set Pr.22 Stall prevention operation level higher according to the
load. (If Pr.22 is set too high, an overcurrent trip (E.OC[]) is likely to
occur.)
Check the capacities of the inverter and the motor.
Perform offline auto tuning
Check the specification of the pulse generator (open collector
output or complementary output) and check the adjustment of the
pulse train and frequency (Pr.385 Frequency for zero input pulse
and Pr.386 Frequency for maximum input pulse).
Countermeasure
Stop the operation.
When Pr.77 Parameter write selection = "0 (initial value)", writing is
enabled only during a stop.
Choose the PU operation mode.
Or, set Pr.77 Parameter write selection = "2" to enable parameter
writing regardless of the operation mode.
Check the Pr.77 setting.
Check the Pr.161 setting.
Check Pr.79, Pr.338, Pr.339, Pr.550, and Pr.551, and select an
operation mode suitable for the purpose.
Under PM motor control, "25" cannot be set in Pr.72. (A sine wave
filter (MT-BSL/BSC) cannot be used under PM motor control.)
Refer to
page
—
339
86
271
339
271, 339
527
528
530
—
273
—
366
245
401
Refer to
page
196
196, 228
196
192
228, 239
207