Mitsubishi Electric FR-A820-00046 (0.4K) Instruction Manual page 754

Operation panel
indication
Name Input phase loss (Standard models and IP55 compatible models only)
When Pr.872 Input phase loss protection selection is enabled ("1") and one of the three-phase power input
Description is lost, the inverter output is shut off. This protective function is not available when Pr.872 is set to the initial value
(Pr.872 = "0"). (Refer to
Check point Check for a break in the cable for the three-phase power supply input.
• Wire the cables properly.
Corrective action
• Repair a break portion in the cable.
Operation panel
E.OLT
indication
Name Stall prevention stop
V/F V/F V/F
If the output frequency has fallen to 0.5 Hz by stall prevention operation and remains for 3 s, a fault (E.OLT)
appears and the inverter output is shut off. OL appears while stall prevention is being activated.
Description
Sensorless Vector Sensorless Sensorless
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 s.
• Check the motor for the use under overload.
• Check that the Pr.865 and Pr.874 values are correct.
Check point (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.)
Corrective action • For the test operation without connecting a motor, select the PM sensorless vector control test operation.
(Refer to
• Also check that the stall prevention (overcurrent) warning (OL) or the stall prevention (overvoltage) warning
(oL) countermeasure is taken.
E.SOT
Operation panel
indication
PM PM PM
Name Loss of synchronism detection
The inverter output is shut off when the motor operation is not synchronized. (This function is only available under
Description
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 point
• Check if a motor is connected under PM sensorless vector control.
• Check if a PM motor other than the MM-CF series 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.
Corrective action
• For the test operation without connecting a motor, select the PM sensorless vector control test operation.
(Refer to
• Drive an IPM motor (MM-CF series).
• When driving an IPM motor other than MM-CF series, offline auto tuning must be performed. (Refer to
519.)
Operation panel
E.LUP
indication
Name Upper limit fault detection
The inverter output is shut off when the load exceeds the upper limit fault detection range. This protective
Description
function is not available in the initial setting of Pr.1490 (Pr.1490 = "9999").
• Check if too much load is applied to the equipment.
Check point
• Check that the load characteristics settings are correct.
• Inspect the equipment.
Corrective action
• Set the load characteristics (Pr.1481 to Pr.1487) correctly.
E.ILF
page 404.)
Magnetic flux Magnetic flux Magnetic flux
Vector Vector PM PM PM
page 218.)
page 218.)
FR-LU08 indication Input phase loss
FR-LU08 indication Stall Prev STP
FR-LU08 indication Motor Step Out
FR-LU08 indication Upper limit fault detection
6. PROTECTIVE FUNCTIONS
6.5 Causes and corrective actions
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