Speed Does Not Accelerate; Unable To Write Parameter Setting; Power Lamp Is Not Lit - Mitsubishi Electric FR-A720-0.4K Instruction Manual

5.5.12 Speed does not accelerate

Check
points
Start command and frequency command are chattering.
Input
The wiring length used for analog frequency command
is too long, and it is causing a voltage (current) drop.
signal
Input signal lines are affected by external EMI.
Pr. 1, Pr. 2, Pr. 18, calibration parameter C2 to C7 settings
are improper.
The maximum voltage (current) input value is not set
during the external operation. (Pr.125, Pr.126, Pr.18)
Torque boost (Pr. 0, Pr. 46, Pr. 112) setting is improper under
V/F control, so the stall prevention function is activated.
V/F pattern is improper when V/F control is performed.
(Pr. 3, Pr. 14, Pr. 19)
Parameter
Setting
Stall prevention (torque limit) function is activated due to
a heavy load.
Auto tuning is not performed under Advanced magnetic
flux vector control, Real sensorless vector control, or
vector control.
The setting of pulse train input is improper.
During PID control, output frequency is automatically controlled to make measured value = set point.
Main
Brake resistor is connected across terminals P/+ and
Circuit P1 or across P1 and PR by mistake. (22K or lower)

5.5.13 Unable to write parameter setting

Check
points
Input
Operation is being performed (signal STF or STR is
signal ON).
You are attempting to set the parameter in the External
operation mode.
Parameter is disabled by the Pr. 77 Parameter write
Parameter
selection setting.
Setting
Key lock is activated by the Pr. 161 Frequency setting/key
lock operation selection setting.
Operation mode and a writing device do not
correspond.

5.5.14 Power lamp is not lit

Check
points
Main
Circuit,
Wiring or installation is improper.
Control
Circuit
Possible Cause
Possible Cause
Possible Cause
Check first when you have a trouble
Countermeasures
Check if the start command and the frequency
command are correct.
Perform analog input bias/gain calibration.
Take countermeasures against EMI, such as using
shielded wires for input signal lines.
Check the settings of Pr. 1 Maximum frequency and Pr. 2
Minimum frequency. If you want to run the motor at 120Hz
or higher, set Pr. 18 High speed maximum frequency.
Check the calibration parameter C2 to C7 settings.
Check the Pr.125 Terminal 2 frequency setting gain
frequency and Pr.126 Terminal 4 frequency setting gain
frequency settings. To operate at 120Hz or higher, set
Pr.18 High speed maximum frequency.
Increase/decrease Pr. 0 Torque boost setting value by
0.5% increments so that stall prevention does not occur.
Set rated frequency of the motor to Pr. 3 Base frequency.
Use Pr. 19 Base frequency voltage to set the base
voltage (e.g. rated motor voltage).
Change Pr. 14 Load pattern selection according to the load
characteristic.
Reduce the load weight.
Set Pr. 22 Stall prevention operation level (Torque limit level)
higher according to the load. (Setting Pr. 22 too large
may result in frequent overcurrent trip (E.OC ).)
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 and
Pr. 386).
Remove the jumper across terminals PR and PX (7.5K
or lower) and connect an option brake resistor (FR-ABR)
across terminals P/+ and PR.
Countermeasures
Stop the operation.
When Pr. 77 = "0" (initial value), write is enabled only
during a stop.
Choose the PU operation mode.
Or, set Pr. 77 = "2" to enable parameter write regardless
of the operation mode.
Check Pr. 77 Parameter write selection setting.
Check Pr. 161 Frequency setting/key lock operation selection
setting.
Check Pr. 79, Pr. 338, Pr. 339, Pr. 550, Pr. 551, and select
an operation mode suitable for the purpose.
Countermeasures
Check for the wiring and the installation.
Power lamp is lit when power is input to the control
circuit (R1/L11, S1/L21).
Refer
to
page
—
294
54
157
294
157,
294
146
159
161
—
152
(100)
—
189
378
361
14
Refer
to
page
307
307
307
393
5
313,
322
Refer
to
page
16
425