Mitsubishi Electric FR-A800 Series Instruction Manual page 790

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
Downloaded from ManualsNet.com
E.UVT
Undervoltage (Standard models and IP55 compatible 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
supply voltage decreases to about 150 VAC (300 VAC for the 400 V class) 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 if the jumper is connected across terminals P/+ and P1.
• Check the devices on the power supply line such as the power supply itself. If this function is activated due to
unstable voltage in the power supply, change the undervoltage level (DC bus voltage value). (Refer to
425.)
• 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.
E.ILF
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
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 for a break in the cable for the three-phase power supply input.
• Wire the cables properly.
• Repair a break portion in the cable.
E.OLT
Stall prevention stop
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. OL appears while stall prevention is being activated.
Sensorless Vector Sensorless Sensorless Vector Vector 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.
(Refer to page 224.)
• Also check that the stall prevention (overcurrent) warning (OL) or the stall prevention (overvoltage) warning
(oL) countermeasure is taken.
search engine
FR-LU08 indication Under Voltage
FR-LU08 indication Input phase loss
page 426.)
FR-LU08 indication Stall prevention STP
page 628 and page 635.)
page
6. PROTECTIVE FUNCTIONS
6.5 Causes and corrective actions
1
2
3
4
5
6
7
8
9
10
789