Mitsubishi Electric FR-A800, Instruction Manual

Page: 913 / 1042

Protective functions Causes and corrective actions
FR-A800 6 - 25
Operation panel
indication
E.BE FR-LU-08 Br.Cct.Fault
Name Brake transistor alarm detection
Description
앫
The inverter trips if a fault due to damage of the brake transistor and such occurs in the
brake circuit.
In such a case, the power supply to the inverter must be shut off
immediately.
앫
Appears when an internal circuit fault occurred for separated converter types and IP55
compatible models.
Check point
앫
Reduce the load inertia.
앫
Check that the brake duty is proper.
Corrective action Replace the inverter.
Operation panel
indication
E.GF FR-LU-08 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.
Operation panel
indication
E.LF FR-LU-08 Output phase loss
Name Output phase loss
Description
The inverter trips if one of the three phases (U, V, W) on the inverter's output side (load side) is
lost.
Check point
앫
Check the wiring. (Check that the motor is normally operating.)
앫
Check that the capacity of the motor used is not smaller than that of the inverter.
앫
Check if a start command is given to the inverter while the motor is coasting.
(PM sensorless vector control)
Corrective action
앫
Wire the cables properly.
앫
Input a start command after the motor stops. Alternatively, use the automatic restart after
instantaneous power failure/flying start function (page 5-571).
(PM sensorless vector control)
Operation panel
indication
E.OHT FR-LU-08 Ext TH relay oper
Name External thermal relay operation
Description
The inverter trips if the external thermal relay provided for motor overheat protection or the
internally mounted thermal relay in the motor, etc. switches ON (contacts open).
This function is available when "7" (OH signal) is set in any of Pr. 178 to Pr. 189 (input terminal
function selection). This protective function is not available in the initial status. (OH signal is not
assigned.)
Check point
앫
Check for motor overheating.
앫
Check that the value "7" (OH signal) is set correctly to any of Pr. 178 to Pr. 189 (input terminal
function selection).
Corrective action
앫
Reduce the load and operation duty.
앫
Even if the relay contacts are reset automatically, the inverter will not restart unless it is reset.