Mitsubishi Electric FR-A820-00046 Instruction Manual page 902

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
Operation panel
indication
Name
Description
Check point
Corrective action
6 - 14
oL
Stall prevention (overvoltage)
When the output voltage of the inverter increases, the stall prevention (overvoltage)
function activates.
The regeneration avoidance function activates due to excessive regenerative power of the
motor. (Refer to page 5-685.)
The following section explains the stall prevention (overvoltage) function.
If the regenerative power of the motor becomes excessive to exceed the
regenerative power consumption capability, this function stops
During deceleration
decreasing the frequency to prevent overvoltage trip. As soon as the
regenerative power has reduced, deceleration resumes.
Check for sudden speed reduction.
Check if the regeneration avoidance function (Pr. 882 to Pr. 886) is being used.
(Refer to page 5-685.)
The deceleration time may change. Increase the deceleration time using Pr. 8 "Deceleration
time".
RB
Regenerative brake pre-alarm (Standard models only)
Appears if the regenerative brake duty reaches or exceeds 85% of the Pr. 70 "Special
regenerative brake duty" value. If the regenerative brake duty reaches 100%, a regenerative
overvoltage (E. OV ) occurs.
Check if the brake resistor duty is not too high.
Check that the Pr. 30 "Regenerative function selection" and Pr. 70 settings are correct.
Set the deceleration time longer.
Check the Pr. 30 and Pr. 70 settings. (Refer to page 5-675.)
TH
Electronic thermal relay function pre-alarm
Appears if the cumulative value of the electronic thermal O/L relay reaches or exceeds 85% of
the preset level of Pr. 9 "Electronic thermal O/L relay". If the value reaches 100% of Pr. 9 setting,
motor overload trip (E.THM) occurs.
Check for large load or sudden acceleration.
Check that the Pr. 9 setting is appropriate. (Refer to page 5-292.)
Reduce the load and frequency of operation.
Set an appropriate value in Pr. 9. (Refer to page 5-292.)
PS
PU stop
The motor is stopped using STOP/RESET key under the mode other than the PU operation
mode. (To enable STOP/RESET key under the mode other than the PU operation mode, set
Pr. 75 "Reset selection/disconnected PU detection/PU stop selection". Refer to page 5-192
for details.)
The motor is stopped by the emergency stop function.
Check for a stop made by pressing STOP/RESET key of the operation panel.
Check for whether the X92 signal is OFF.
Turn the start signal OFF and release with PU/EXT key.
Turn ON the X92 signal and OFF the start signal for release.
Protective functions
FR-LU-08 oL
FR-LU-08 RB
FR-LU-08 TH
FR-LU-08 PS