Mitsubishi FR-A800

Causes and corrective actions
PROTECTIVE FUNCTIONS
661
6 5
Operation panel
indication
E.OSD
FR-PU07 E.OSd
Name
Speed deviation excess detection
Description
• The inverter trips 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 controlled in
accordance 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 point
• Check that the values of Pr.285 and Pr.853 Speed deviation time are correct.
• Check for sudden load change.
• Check that the number of encoder pulses does not differ from the actual number of Pr.369 Number of
encoder pulses.
Corrective action
•Set Pr.285 and Pr.853 correctly.
• Keep the load stable.
•Set Pr.369 correctly.
Operation panel
indication
E.ECT FR-PU07 E.ECT
Name
Signal loss detection
Description
The inverter trips when the encoder signal is shut off under orientation control, encoder feedback control or
vector control. This protective function is not available in the initial status.
Check point
• Check for the encoder signal loss.
• Check that the encoder specifications are correct.
• Check for a loose connector.
• Check that the switch setting of FR-A8AP (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.
Corrective action
• Remedy the signal loss.
• Use an encoder that meets the specifications.
• Make connection securely.
• Make a switch setting of FR-A8AP (option) correctly. (Refer to page 63.)
• 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 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
E.OD
FR-PU07 E.Od
Name
Excessive position fault
Description
The inverter trips when the difference between the position command and position feedback exceeds Pr.427
Excessive level error under position control.
Check point
• Check that the position detecting encoder mounting orientation matches the parameter.
• Check that the load is not large.
• Check that the Pr.427, Pr.369 Number of encoder pulses settings are correct.
Corrective action
• Check the parameters.
• Reduce the load.
•Set Pr.427, Pr.369 correctly.
Operation panel
indication
E.MB1 to 7
to
FR-PU07 E.MB1 Fault to E.MB7 Fault
Name
Brake sequence fault
Description
• The inverter trips when a sequence error occurs during use of the brake sequence function (Pr.278 to
Pr.285). This protective function is not available in the initial status. (The brake sequence function is invalid.)
(For the details of fault record, refer to page 473.)
Check point
Find the cause of the fault occurrence.
Corrective action
Check the set parameters and perform wiring properly.
Vector
Vector
Vector
Vector
Vector
Vector