Mitsubishi Electric FR-A800, Instruction Manual

Page: 920 / 1042

Causes and corrective actions Protective functions
6 - 32
Operation panel
indication
E.OSD FR-LU-08 Spd deviation fault
Name Speed deviation excess detection
Description
앫
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.
앫
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
앫
Check that the values of Pr. 285 and Pr. 853 "Speed deviation time" are correct.
앫
Check for sudden load change.
앫
Check that the number of encoder pulses does not differ from the actual number of Pr. 369
(851) "Number of encoder pulses".
Corrective action
앫
Set Pr. 285 and Pr. 853 correctly.
앫
Keep the load stable.
앫
Set Pr. 369 (851) correctly.
Operation panel
indication
E.ECT FR-LU-08 Encoder signal loss
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
앫
Check for the encoder signal loss.
앫
Check that the encoder specifications are correct.
앫
Check for a loose connector.
앫
Check that the switch setting of a vector control compatible option is correct.
앫
Check that the power is supplied to the encoder. Alternatively, check that the power is not
supplied to the encoder later than the inverter.
앫
Check that the voltage of the power supplied to the encoder is the same as the encoder
output voltage.
Corrective action
앫
Remedy the signal loss.
앫
Use an encoder that meets the specifications.
앫
Make connection securely.
앫
Make a switch setting of a vector control compatible option correctly. (Refer to page 2-63.)
앫
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.
앫
Make the voltage of the power supplied to the encoder the same as the encoder output
voltage.
Vector Vector Vector