Mitsubishi Electric 800 Series Instruction Manual page 640

Abbreviation E.UVT
Name
Undervoltage (Standard models only)
If the power supply voltage of the inverter decreases, the control circuit will not perform normal functions. In
addition, the motor torque will be insufficient and/or heat generation will increase. To prevent this, if the power
Description
supply voltage decreases to about 440 VAC or below, this function shuts off the inverter output.
When a jumper is not connected across P/+ and P1, the undervoltage protective function is activated.
When undervoltage protection is activated, the IPF signal is output. (Refer to
• Check if a high-capacity motor is driven.
Check point
• Check if the jumper is connected across terminals P/+ and P1.
• Check the power supply system equipment such as the power supply.
Corrective action
• Do not remove the jumper across terminals P/+ and P1 except when connecting a DC reactor.
• If the problem still persists after taking the above measure, contact your sales representative.
Abbreviation E.ILF
Name
Input phase loss (Standard models only)
When Pr.872 Input phase loss protection selection is enabled ("1") and one of the three-phase power
Description
input 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.
Abbreviation E.OLT
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 trips. OL appears while stall prevention is being activated.
Description
Sensorless Sensorless Sensorless Vector
When speed control is performed, a fault (E.OLT) appears and the inverter trips 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 a test run without connecting a motor, select the PM sensorless vector control test operation. (Refer to
page
• Also check that the stall prevention (overcurrent) warning (OL) or the stall prevention (overvoltage) warning
(oL) countermeasure is taken.
Abbreviation
E.SOT
Name
Loss of synchronism detection
The inverter trips when the motor operation is not synchronized. (This function is only available under PM
Description
sensorless vector control.)
• Check that the PM motor is not driven overloaded.
Check point
• 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.
• Set the acceleration time longer.
• Reduce the load.
• Check the connection of the PM motor.
Corrective action
• For a test run without connecting a motor, select the PM sensorless vector control test operation. (Refer to
page
• Offline auto tuning must be performed. (Refer to
page
Magnetic flux Magnetic flux Magnetic flux
Vector Vector PM PM PM
139.)
PM PM PM
139.)
Causes and corrective actions
FR-LU08
Under Voltage
FR-PU07
FR-LU08
Input phase loss
FR-PU07
326)
FR-LU08
Stll Prev STP
FR-PU07
FR-LU08
Motor step out
FR-PU07
page 436.)
PROTECTIVE FUNCTIONS
page 515.)
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