Mitsubishi Electric Melservo JE Series Instruction Manual page 179

7. SPECIAL ADJUSTMENT FUNCTIONS
7.3.2 Instantaneous power failure tough drive function
The instantaneous power failure tough drive function avoids [AL. 10 Undervoltage] even when an
instantaneous power failure occurs during operation. When the instantaneous power failure tough drive
activates, the function will increase the tolerance against instantaneous power failure using the electrical
energy charged in the capacitor in the servo amplifier and will change an alarm level of [AL. 10
Undervoltage] simultaneously. The [AL. 10.1 Voltage drop in the control circuit power] detection time for the
control circuit power supply can be changed by [Pr. PF25 SEMI-F47 function - Instantaneous power failure
detection time]. In addition, [AL. 10.2 Voltage drop in the main circuit power] detection level for the bus
voltage is changed automatically.
POINT
MBR (Electromagnetic brake interlock) will not turn off during the instantaneous
power failure tough drive.
When "Enabled (_ _ _ 1)" is selected for "Torque limit function selection at
instantaneous power failure" in [Pr. PA26], and if an instantaneous power failure
occurs during operation, the torque at acceleration will be limited to reduce
electric energy consumption from the capacitor in the servo amplifier, and the
time to trigger [AL. 10.2 Voltage drop in the main circuit power] will be delayed.
Thus, you can set a longer time in [Pr. PF25 SEMI-F47 function - Instantaneous
power failure detection time].
When the load at an instantaneous power failure is large, a drop in bus voltage
may cause [AL. 10.2] regardless of the set value of [Pr. PF25 SEMI-F47 function
- Instantaneous power failure detection time].
The setting range of [Pr. PF25 SEMI-F47 function - Instantaneous power failure
detection time] is from 300 ms to 2000 ms. Setting the value over 500 ms will be
clamped with 500 ms.
To comply with SEMI-F47 standard, it is unnecessary to change the initial value
(200 ms).
However, when the instantaneous power failure time exceeds 200 ms, and the
instantaneous power failure voltage is less than 70% of the rated input voltage,
the power may be normally turned off even if a value larger than 200 ms is set in
the parameter.
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