Mitsubishi FR-A721-11K Instruction Manual page 152

Operation Panel
Indication
Description
Corrective action
(2) Warning
When the protective circuit is activated, the output is not shut off.
Operation Panel
Indication
Name
Stall prevention (overcurrent)
During
acceleration
During
constant
Description
speed
operation
During
deceleration
Check point
Corrective action
Operation Panel
Indication
Name
Stall prevention (overvoltage)
During
Description
deceleration
Check point
The deceleration time may change.
Corrective action
Increase the deceleration time using Pr. 8 Deceleration time.
Err.
The RES signal is ON
The PU and inverter cannot make normal communication (contact fault of the connector)
When the voltage drops in the inverter's input side.
When the control circuit power (R1/L11, S1/L21) and the main circuit power (R/L1, S/L2, T/L3) are
connected to a separate power, it may appear at turning ON of the main circuit. It is not a fault.
Turn OFF the RES signal.
Check the connection of the PU and inverter.
Check the voltage on the inverter's input side.
OL
When the output current (output torque during Real sensorless vector control or vector
control) of the inverter exceeds the stall prevention operation level (Pr. 22 Stall prevention
operation level, etc.), this function stops the increase in frequency until the overload
current decreases to prevent the inverter from resulting in overcurrent trip. When the
overload current has decreased below stall prevention operation level, this function
increases the frequency again.
When the output current (output torque during Real sensorless vector control or vector
control) of the inverter exceeds the stall prevention operation level (Pr. 22 Stall prevention
operation level, etc.), this function reduces frequency until the overload current
decreases to prevent the inverter from resulting in overcurrent trip. When the overload
current has decreased below stall prevention operation level, this function increases the
frequency up to the set value.
When the output current (output torque during Real sensorless vector control or vector
control) of the inverter exceeds the stall prevention operation level (Pr. 22 Stall prevention
operation level, etc.), this function stops the decrease in frequency until the overload
current decreases to prevent the inverter from resulting in overcurrent trip. When the
overload current has decreased below stall prevention operation level, this function
decreases the frequency again.
Check that the Pr. 0 Torque boost setting is not too large.
Check that the Pr. 7 Acceleration time and Pr. 8 Deceleration time settings are not too small.
Check that the load is not too heavy.
Are there any failure in peripheral devices?
Check that the Pr. 13 Starting frequency is not too large.
· Check the motor for use under overload.
Check that the Pr. 22 Stall prevention operation level is appropriate.
Increase or decrease the Pr. 0 Torque boost value 1% by 1% and check the motor status. (Refer to page 59.)
Set a larger value in Pr. 7 Acceleration time and Pr. 8 Deceleration time. (Refer to page 61.)
Reduce the load weight.
Try Advanced magnetic flux vector control, Real sensorless vector control or vector control.
Change the Pr. 14 Load pattern selection setting.
Set stall prevention operation current in Pr. 22 Stall prevention operation level. (The initial value is
150%.) The acceleration/deceleration time may change. Increase the stall prevention operation level
with Pr. 22 Stall prevention operation level, or disable stall prevention with Pr. 156 Stall prevention
operation selection. (Use Pr. 156 to set either operation continued or not at OL operation.)
oL
If the regenerative energy of the motor becomes excessive and exceeds the
regenerative energy consumption capability, this function stops the decrease in
frequency to prevent overvoltage trip. As soon as the regenerative energy has
decreased, deceleration resumes.
If the regenerative energy of the motor becomes excessive when regeneration
avoidance function is selected (Pr. 882 = 1), this function increases the speed to
prevent overvoltage trip. (Refer to Chapter 4 of
Check for sudden speed reduction.
Regeneration avoidance function (Pr. 882 to Pr. 886) is being used? (Refer to Chapter 4 of
Instruction Manual (Applied).)
Causes and corrective actions
FR-PU04
OL
FR-PU07
FR-PU04
oL
FR-PU07
the Instruction Manual (Applied).)
5
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