Mitsubishi Electric FR-A820-00046 (0.4K) Instruction Manual page 760

Operation panel
indication
Name Overspeed occurrence
The inverter output is shut off when the motor speed exceeds the Pr.374 Overspeed detection level under
Description encoder feedback control, Real sensorless vector control, Vector control, and PM sensorless vector control. This
protective function is not available in the initial status.
• Check that the Pr.374 setting is correct.
Check point • Check that the number of encoder pulses does not differ from the actual number of Pr.369 (Pr.851) Number
of encoder pulses. (Under encoder feedback control or vector control)
• Set the Pr.374 correctly.
Corrective action
• Set Pr.369 (Pr.851) correctly. (Under encoder feedback control or vector control)
Operation panel
E.OSD
indication
Vector Vector Vector
Name Speed deviation excess detection
• The inverter output is shut off if the motor speed is increased or decreased under the influence of the load etc.
during Vector control with Pr.285 Overspeed detection frequency set and cannot be controlled in accordance
Description with the speed command value.
• If the motor is accelerated against the stop command accidentally, the deceleration check function (Pr.690) is
activated to stop the inverter output.
• Check that the settings of Pr.285 and Pr.853 Speed deviation time are correct.
• Check for sudden load change.
Check point
• Check that the setting of Pr.369 (Pr.851) Number of encoder pulses does not differ from the actual number
of encoder pulses.
• Set Pr.285 and Pr.853 correctly.
Corrective action • Keep the load stable.
• Set Pr.369 (Pr.851) correctly.
Operation panel
E.ECT
indication
Name Signal loss detection
The inverter output is shut off when the encoder signal is shut off under orientation control, encoder feedback
Description
control or vector control. This protective function is not available in the initial status.
• Check for the encoder signal loss.
• Check that the encoder specifications are correct.
• Check for a loose connector.
Check point • Check that the switch setting of a Vector control compatible option is correct.
• Check that the power is supplied to the encoder. Alternatively, check that the power is not supplied to the
encoder later than the inverter.
• Check that the voltage of the power supplied to the encoder is the same as the encoder output voltage.
• Remedy the signal loss.
• Use an encoder that meets the specifications.
• Make connection securely.
• Make a switch setting of a Vector control compatible option correctly. (Refer to
• Supply the power to the encoder. Or supply the power to the encoder at the same time when the power is
Corrective action
supplied to the inverter.
If the power is supplied to the encoder after sent to the inverter, check that the encoder signal is properly sent
and set "0 (initial value)" in Pr.376 Encoder signal loss detection enable/disable selection to disable signal
loss detection.
• Make the voltage of the power supplied to the encoder the same as the encoder output voltage.
Operation panel
indication
Vector Vector Vector
Name Excessive position fault
The inverter output is shut off when the difference between the position command and position feedback
Description exceeds the setting of Pr.427 Excessive level error during position control. This protective function is not
available in the initial status.
• Check that the position detecting encoder mounting orientation matches the parameter.
Check point • Check that the load is not large.
• Check that the settings of Pr.427 and Pr.369 (Pr.851) Number of encoder pulses are correct.
• Check the parameters.
Corrective action • Reduce the load.
• Set Pr.427 and Pr.369 (Pr.851) correctly.
E.OS
E.OD
FR-LU08 indication Overspeed occurrence
FR-LU08 indication Spd deviation fault
FR-LU08 indication Encoder signal loss
page
FR-LU08 indication Position fault
6. PROTECTIVE FUNCTIONS
6.5 Causes and corrective actions
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