Mitsubishi Electric MR-J4 Instruction Manual page 551

17. APPLICATION OF FUNCTIONS
(b) 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 immunity to instantaneous power failures 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. PX28 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 selecting "Enabled (_ _ _ 1)" for "Torque limit function selection at
instantaneous power failure" in [Pr. PX23], if an instantaneous power failure
occurs during operation, you can save electric energy charged in the capacitor in
the servo amplifier by limiting torque at acceleration. You can also delay the time
until the occurrence of [AL. 10.2 Voltage drop in the main circuit power]. Doing
this will enable you to set a longer time in [Pr. PX28 SEMI-F47 function -
Instantaneous power failure detection time].
When the load of instantaneous power failure is large, the undervoltage alarm
([AL. 10.2]) caused by the bus voltage drop may occur regardless of the set
value of [Pr. PX28 SEMI-F47 function - Instantaneous power failure detection
time].
The external dynamic brake cannot be used for compliance with SEMI-F47
standard. Do not assign DB (Dynamic brake interlock) in [Pr. PD07] to [Pr.
PD09]. Failure to do so will cause the servo amplifier to become servo-off when
an instantaneous power failure occurs.
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