Mitsubishi Electric FR-A820-00046 Instruction Manual page 1067

Protective functions
Operation panel
indication
Name
Description
Check point
Corrective action
Operation panel
indication
Name
Description
Check point
Corrective action
FR-A800
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 and Pr. 1016 settings.
Check the motor for operation under overload.
Reduce the load.
Causes and corrective actions
FR-LU-08 Ext TH relay oper
FR-LU-08 PTC thermistor oper
6 - 27