Mitsubishi Electric 800 Series Instruction Manual page 26

 Undervoltage
Operation panel
indication
Description
Check point
Corrective action
Reference
 Input phase loss
Operation panel
indication
Description
Check point
Corrective action
Reference
 Stall prevention stop
Operation panel
indication
Description
Check point
Corrective action
Reference
 Loss of synchronism detection
Operation panel
indication
Description
Check point
Corrective action
Reference
25
2. Protective Functions
2.5 Causes and corrective actions
E.UVT
When a PM motor is used, the protective function is activated in the following case: a fault such as power failure
or voltage drop occurs, the converter voltage drops to cause the motor to coast, and restarting and coasting are
repeated by the automatic restart after instantaneous power failure function.
Check that no fault is found in the power supply.
Supply appropriate power.
FR-E800 Instruction Manual (Function)
E.ILF
When Pr.872 Input phase loss protection selection is enabled ("1") and one of the three-phase power input
is lost, the inverter output is shut off. This protective function is not available when "0" is set in Pr.872.
Check for a break in the cable for the three-phase power supply input.
• Wire the cables properly.
• Repair a break portion in the cable.
FR-E800 Instruction Manual (Function)
E.OLT
V/F V/F V/F Magnetic flux Magnetic flux Magnetic flux
If the output frequency has fallen to 0.5 Hz by stall prevention operation and remains for 3 seconds, a fault
(E.OLT) appears and the inverter is shut off. OLC or OLV appears while stall prevention is being activated.
Sensorless Sensorless Sensorless PM PM PM
When speed control is performed, a fault (E.OLT) appears and the inverter output is shut off if frequency drops
to the Pr.865 Low speed detection (initial value is 1.5 Hz) setting by torque limit operation and the output torque
exceeds the Pr.874 OLT level setting (initial value is 150%) setting and remains 3 seconds.
• Check the motor for the use under overload.
• Check that the Pr.865 and Pr.874 values are correct.
(Check the Pr.22 Stall prevention operation level setting under V/F control and Advanced magnetic flux
vector control.)
• Check if a motor is connected under PM sensorless vector control.
• Reduce the load.
• Change the Pr.22, Pr.865, and Pr.874 values. (Check the Pr.22 setting under V/F control and Advanced
magnetic flux vector control.)
• For the test operation without connecting a motor, select the PM sensorless vector control test operation.
• Also check that the stall prevention (overcurrent) warning (OLC) or the stall prevention (overvoltage) warning
(OLV) countermeasure is taken.
FR-E800 Instruction Manual (Function)
E.SOT
PM PM PM
The inverter output is shut off when the motor operation is not synchronized. (This function is only available under
PM sensorless vector control.)
• 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 sensorless vector control.
• Check if a motor other than PM motors is driven.
• 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 the test operation without connecting a motor, select the PM sensorless vector control test operation.
• When driving a PM motor, offline auto tuning must be performed.
FR-E800 Instruction Manual (Function)