Mitsubishi Electric FR-F820-00046, Instruction Manual

Page: 835 / 940

Protective functions Causes and corrective actions
FR-F800 6 - 23
Operation panel
indication
E.SOT
FR-LU08 Motor Step Out
Name Loss of synchronism detection
Description
The inverter trips when the motor operation is not synchronized. (This function is only available
under PM motor control.)
Check point
Check that the PM motor is not driven overloaded.
Check if a start command is given to the inverter while the PM motor is coasting.
Check if a motor is connected under PM motor control.
Check if a PM motor other than the MM-EFS/MM-THE4 series is driven.
Corrective action
Set the acceleration time longer.
Reduce the load.
If the inverter restarts during coasting, set Pr. 57 "Restart coasting time"
≠
"9999", and select
the automatic restart after instantaneous power failure.
Check the connection of the IPM motor.
For a test run without connecting a motor, select the PM motor control test operation. (Refer
to page 5-42.)
Drive an IPM motor (MM-EFS/MM-THE4 series)
When driving an IPM motor other than MM-EFS/MM-THE4 series, offline auto tuning must
be performed. (Refer to page 5-316.)
Operation panel
indication
E.LUP FR-LU08 Upper limit fault
Name Upper limit fault detection
Description
When the load exceeds the upper limit fault detection range, the inverter trips. This protective
function is not available in the initial setting of Pr. 1490 (Pr. 1490 = "9999").
Check point
Check if too much load is applied to the equipment.
Check that the load characteristics settings are correct.
Corrective action
Inspect the equipment.
Set the load characteristics (Pr. 1481 to Pr. 1487) correctly.
Operation panel
indication
E.LDN FR-LU08 Lower limit fault
Name Lower limit fault detection
Description
When the load falls below the lower limit fault detection range, the inverter trips. This protective
function is not available in the initial setting of Pr. 1491 (Pr. 1491 = "9999").
Check point
Check if the equipment load is too light.
Check that the load characteristics settings are correct.
Corrective action
Inspect the equipment.
Set the load characteristics (Pr. 1481 to Pr. 1487) correctly.
Operation panel
indication
E.GF FR-LU08 Ground Fault
Name Output side earth (ground) fault overcurrent
Description
The inverter trips if an earth (ground) fault overcurrent flows due to an earth (ground) fault that
occurred on the inverter's output side (load side).
Check point Check for an earth (ground) fault in the motor and connection cable.
Corrective action Remedy the earth (ground) fault portion.
PM PM PM