Mitsubishi Electric FR-F720-0.75K to 110K Instruction Manual page 282

Check
points
Pr. 0 Torque boost setting is improper when V/F control is
used.
Pr. 78 Reverse rotation prevention selection is set.
Pr. 79 Operation mode selection setting is wrong.
Bias and gain (calibration parameter C2 to C7) settings
are improper.
Pr. 13 Starting frequency setting is greater than the
running frequency.
Frequency settings of various running frequency (such
as multi-speed operation) are zero.
Especially, Pr. 1 Maximum frequency is zero.
Parameter
Pr. 15 Jog frequency setting is lower than Pr. 13 Starting
Setting
frequency.
Operation mode and a writing device do not match.
Start signal operation selection is set by the Pr. 250 Stop
selection
Inverter decelerated to a stop when power failure
deceleration stop function is selected.
Automatic restart after instantaneous power failure
function or power failure stop function is activated.
(Performing overload operation during input phase loss
may cause voltage insufficiency, and that may result in
detection of power failure.)
Load is too heavy.
Load
Shaft is locked.
Possible Cause
Check first when you have a trouble
Countermeasures
Increase Pr. 0 setting by 0.5% increments while
observing the rotation of a motor.
If that makes no difference, decrease the setting.
Check the Pr. 78 setting.
Set Pr. 78 when you want to limit the motor rotation to
only one direction.
Select the operation mode which corresponds with input
methods of start command and frequency command.
Check the bias and gain (calibration parameter C2 to C7)
settings.
Set running frequency higher than Pr. 13.
The inverter does not start if the frequency setting signal
is less than the value set in Pr. 13.
Set the frequency command according to the
application.
Set Pr. 1 higher than the actual frequency used.
Set Pr. 15 Jog frequency higher than Pr. 13 Starting
frequency.
Check Pr. 79, Pr. 338, Pr. 339, Pr. 550, Pr. 551, and select
an operation mode suitable for the purpose.
Check Pr. 250 setting and connection of STF and STR
signals.
When power is restored, ensure the safety, and turn
OFF the start signal once, then turn ON again to restart.
Inverter restarts when Pr. 261="2, 22".
Set Pr. 872 Input phase loss protection selection = "1"
(input phase failure protection active).
Disable the automatic restart after instantaneous
power failure function and power failure stop function.
Reduce the load.
Increase the acceleration time if the automatic restart
after instantaneous power failure function or power
failure stop function occurred during acceleration.
Reduce the load.
Inspect the machine (motor).
Refer
to
page
74
175
177
167
98
82
90
177,
186
119
145
141,
145,
151
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