Mitsubishi Electric FR-D720-008 Instruction Manual page 258

Causes and corrective actions
Operation panel
E.ILF
indication
Input phase loss ∗
Name
Inverter trips when function valid setting (=1) is selected in Pr. 872 Input phase loss protection selection and one phase of
the three phase power input is lost. (Refer to page 144).
Description
It may function if phase-to-phase voltage of the three-phase power input becomes largely unbalanced.
When the setting of Pr. 872 Input phase loss protection selection is the initial value (Pr. 872 ="0"), this warning does not
occur.
Check for a break in the cable for the three-phase power supply input.
Check point
Check that phase-to-phase voltage of the three-phase power input is not largely unbalanced.
Wire the cables properly.
Repair a break portion in the cable.
Corrective action
Check the Pr. 872 Input phase loss protection selection setting.
Set Pr. 872 = "0" (without input phase loss protection) when three-phase input voltage is largely unbalanced.
∗ Available only for three-phase power input specification model.
Operation panel
E.OLT
indication
Name
Stall prevention
If the output frequency has fallen to 1Hz by stall prevention operation and remains for 3s, a fault (E.OLT) appears
Description
and the inverter trips. OL appears while stall prevention is being activated.
E.OLT may not occur if stall prevention (OL) is activated during output phase loss.
Check point Check the motor for use under overload. (Refer to page 78).
Corrective action Reduce the load weight. (Check the Pr. 22 Stall prevention operation level setting.)
Operation panel
E.BE
indication
Name Brake transistor alarm detection
When a brake transistor alarm has occurred due to the large regenerative energy from the motor etc., the brake
transistor alarm is detected and the inverter trips.
Description
In this case, the inverter must be powered off immediately.
Reduce the load inertia.
Check point
Check that the frequency of using the brake is proper.
Check that the brake resistor selected is correct.
Corrective action
Replace the inverter.
Operation panel
E.GF
indication
Name
Output side earth (ground) fault overcurrent at start
The inverter trips if an earth (ground) fault overcurrent flows at start due to an earth (ground) fault that occurred on
the inverter's output side (load side). Whether this protective function is used or not is set with Pr. 249 Earth (ground)
Description
fault detection at start. When the setting of Pr. 249 Earth (ground) fault detection at start is the initial value (Pr. 249 ="0"),
this warning does not occur.
Check point Check for a ground fault in the motor and connection cable.
Corrective action Remedy the ground fault portion.
Operation panel
E.LF
indication
Name Output phase loss
If one of the three phases (U, V, W) on the inverter's output side (load side) is lost during inverter operation (except
Description
during DC injection brake operation and when output frequency is under 1Hz), inverter stops the output. Whether the
protective function is used or not is set with Pr.251 Output phase loss protection selection.
Check the wiring. (Check that the motor is normal.)
Check point
Check that the capacity of the motor used is not smaller than that of the inverter.
Wire the cables properly.
Corrective action
Check the Pr. 251 Output phase loss protection selection settting.
254
FR-PU04 Fault 14
FR-PU07 Input phase loss
FR-PU04
Stll Prev STP (OL shown during stall prevention operation)
FR-PU07
FR-PU04
Br. Cct. Fault
FR-PU07
FR-PU04
Ground Fault
FR-PU07
FR-PU04
E.LF
FR-PU07