Mitsubishi Electric FR-D720S SC EC, Instruction Manual

Page: 460 / 512

Check first when you have troubles Troubleshooting
7 - 24
7.6.4 Motor generates heat abnormally
7.6.5 Motor rotates in opposite direction
7.6.6 Speed greatly differs from the setting
Check points Possible Cause Countermeasures
Refer to
Page
Motor
Motor fan is not working
(Dust is accumulated.) Clean the motor fan.
Improve the environment.
—
Phase to phase insulation of the motor is
insufficient.
Check the insulation of the motor. —
Main Circuit
The inverter output voltage (U, V, W) are
unbalanced. Check the output voltage of the inverter.
Check the insulation of the motor.
8-2
Parameter
Setting The Pr. 71 "Applied motor" setting is
wrong.
Check the Pr. 71 "Applied motor" setting. 6-72
— Motor current is large. Refer to "7.6.11 Motor current is too large" 7-28
Check points Possible Cause Countermeasures
Refer to
Page
Main Circuit
Phase sequence of output terminals U, V
and W is incorrect.
Connect phase sequence of the output
cables (terminal U, V, W) to the motor cor-
rectly
3-6
Input signal
The start signals (forward rotation, reverse
rotation) are connected improperly. Check the wiring. (STF: forward rotation,
STR: reverse rotation)
3-13
Adjustment by the output frequency is
improper during the reversible operation
with Pr. 73 "Analog input selection" set-
ting.
Check the setting of Pr. 125, Pr. 126, C2 to
C7.
6-153
Parameter
Setting Pr. 40 "RUN key rotation direction selec-
tion" setting is incorrect.
Check the Pr. 40 setting. 6-282
Check points Possible Cause Countermeasures
Refer to
Page
Input signal
Frequency setting signal is incorrectly
input.
Measure the input signal level. —
The input signal lines are affected by
external EMI.
Take countermeasures against EMI such
as using shielded wires for input signal
lines.
3-44
Parameter
Setting
Pr. 1, Pr. 2, Pr. 18, calibration parameter
C2 to C7 settings are improper.
Check the settings of Pr. 1 "Maximum fre-
quency", Pr. 2 "Minimum frequency",
Pr. 18 "High speed maximum frequency".
6-40
Check the calibration parameter C2 to C7
settings.
6-153
Pr. 31 to Pr. 36 "Frequency jump" settings
are improper.
Narrow down the range of frequency jump. 6-42
Load
Stall prevention is activated due to a heavy
load.
Reduce the load weight. —
Parameter
Setting
Set Pr. 22 "Stall prevention operation level
"higher according to the load. (Setting Pr.
22 too large may result in frequent over-
current trip (E.OC
).)
6-33
Motor
Check the capacities of the inverter and
the motor.
—