Mitsubishi Electric FR-F740 EC Instruction Manual page 597

Troubleshooting
Check points Possible cause
Parameter
Setting
Load
FR-F700 EC
Pr. 0 "Torque boost" setting is improper
when V/F control is used.
Pr. 78 "Reverse rotation prevention selec-
tion" 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 fre-
quency (such as multi-speed operation)
are zero. Especially, Pr. 1 "Maximum fre-
quency" is zero.
Pr. 15 "Jog frequency" setting is lower
than Pr. 13 "Starting 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 insuf-
ficiency, and that may result in detection of
power failure.)
DC feeding mode 1 or mode 2 is not
selected in Pr. 30 "Regenerative function
selection" even though the DC is fed
through terminal N/– and P/+.
Load is too heavy.
Shaft is locked.
Check first when you have troubles
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 corre-
sponds with input methods of start com-
mand 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 and
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.
Set the DC feeding mode in Pr. 30.
Reduce the load.
Inspect the machine (motor).
Refer to
page
6-39
6-220
6-233
6-199
6-79
6-54
6-66
6-229,
6-244
6-116
6-162
6-153,
6-162
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