Mitsubishi Electric FR-F820-00077 Instruction Manual page 836

Causes and corrective actions
Operation panel
indication
Name
Description
Check point
Corrective action
Operation panel
indication
Name
Description
Check point
Corrective action
Operation panel
indication
Name
Description
Check point
Corrective action
6 - 24
E.LF
Output phase loss
The inverter trips if one of the three phases (U, V, W) on the inverter's output side (load side) is
lost.
Check the wiring. (Check that the motor is normally operating.)
Check that the capacity of the motor used is not smaller than that of the inverter.
Check if a start command is given to the inverter while the motor is coasting.
(PM motor control)
Wire the cables properly.
Input a start command after the motor stops. Alternatively, use the automatic restart after
instantaneous power failure/flying start function (page 5-423).
(PM motor control)
E.OHT
External thermal relay operation
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 for motor overheating.
Check that the value "7" (OH signal) is set correctly to any of Pr. 178 to Pr. 189 (input terminal
function selection).
Reduce the load and operation duty.
Even if the relay contacts are reset automatically, the inverter will not restart unless it is reset.
E.PTC
PTC thermistor operation
The inverter trips if resistance of the PTC thermistor connected between the terminal 2 and
terminal 10 is equal to or higher than the Pr. 561 "PTC thermistor protection level" setting for a
continuous time equal to or longer than the setting value in Pr. 1016 "PTC thermistor protection
detection time". When the initial value (Pr. 561 = "9999") is set, this protective function is not
available.
Check the connection with the PTC thermistor.
Check the Pr. 561, Pr. 1016 setting.
Check the motor for operation under overload.
Reduce the load.
Protective functions
FR-LU08 Output phase loss
FR-LU08 Ext TH relay oper
FR-LU08 PTC thermistor oper