Mitsubishi FR-A721-11K Instruction Manual page 162

Operation Panel
E.MB1 to 7
Indication
Name
Brake sequence fault
The inverter output is stopped when a sequence error occurs during use of the brake sequence
Description function (Pr. 278 to Pr. 285). This fault is not available in the initial status (brake sequence function is
invalid). (Refer to Chapter 4 of
Check point
Find the cause of alarm occurrence.
Corrective action
Check the set parameters and perform wiring properly.
Operation Panel
E.OS
Indication
Name
Overspeed occurrence
Stops the inverter output when the motor speed exceeds the Pr. 374 Overspeed detection level during
Description
encoder feedback control Real sensorless vector control and vector control. This fault is not available
in the initial status.
Check that the Pr. 374 Overspeed detection level value is correct.
Check point
Check that the number of encoder pulses does not differ from the actual number of encoder pulses.
Set the Pr. 374 Overspeed detection level value correctly.
Corrective action
Set the correct number of encoder pulses in Pr. 369 Number of encoder pulses.
Operation Panel
E.OSD
Indication
Name
Speed deviation excess detection
Stops the inverter output if the motor speed is increased or decreased under the influence of the load
etc. during vector control with Pr. 285 Speed deviation excess detection frequency set and cannot be
Description
controlled in accordance with the speed command value.
This fault is not available in the initial status.
Check that the values of Pr. 285 Speed deviation excess detection frequency and Pr. 853 Speed deviation
time are correct.
Check point
Check for sudden load change.
Check that the number of encoder pulses does not differ from the actual number of encoder pulses.
Set Pr. 285 Speed deviation excess detection frequency and Pr. 853 Speed deviation time correctly.
Corrective action Keep load stable.
Set the correct number of encoder pulses in Pr. 369 Number of encoder pulses.
Operation Panel
E.ECT
Indication
Name
Signal loss detection
Trips the inverter when the encoder signal is shut off under orientation control, encoder feedback
Description
control or vector control. This fault 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 the FR-A7AP/FR-A7AL (option) is correct.
Check that the power is supplied to the encoder. Or, check that the power is not supplied to the
encoder later than the inverter.
Remedy the signal loss.
Use an encoder that meets the specifications.
Make connection securely.
Make a switch setting of the FR-A7AP/FR-A7AL (option) correctly. (Refer to page 29)
Corrective action
Supply the power to the encoder. Or supply the power to the encoder at the same time when the
power is supplied to the inverter.
If the power is supplied to the encoder after the inverter, check that the encoder signal is securely
sent and set "0" in Pr. 376.
Causes and corrective actions
⎯⎯
FR-PU04
to
FR-PU07 E.MB1 Fault to E.MB7 Fault
the Instruction Manual (Applied).)
FR-PU04
E. OS
FR-PU07
FR-PU04
E. OSd
FR-PU07
FR-PU04
E. ECT
FR-PU07
5
155