Mitsubishi Electric M80 Series Maintenance Manual page 15

(7) Troubleshooting
Use a motor with electromagnetic brakes or
establish an external brake mechanism for the
purpose of holding; this serves as counter-
measures for possible hazardous situation
caused by power failure or product fault.
Use a double circuit structure for the electro-
magnetic brake's operation circuit so that the
brakes will activate even when the external
emergency stop signal is issued.
The machine could suddenly restart when the power is restored after an instantaneous power failure, so
stay away from the machine. (Design the machine so that the operator safety can be ensured even if the
machine restarts.)
To secure the absolute position, do not shut off the servo drive unit's control power supply when its battery
voltage drops (warning 9F) in the servo drive unit side.
If the battery voltage drop warning alarm occurs in the controller side, make sure to back up the machining
programs, tool data and parameters, etc. with the input/output device before replacing the battery. Depend-
ing on the level of voltage drop, memory loss could have happened. In that case, reload all the data backed
up before the alarm occurrence.
(8) Maintenance, inspection and part replacement
Periodically back up the programs, tool data and parameters to avoid potential data loss. Also, back up
those data before maintenance and inspections.
When replacing the battery on the controller side, the machining programs, tool data and parameters
should be backed up with the input/output device beforehand. In case the memory is damaged in replacing
the batteries, reload all the data backed up before replacing the battery.
The electrolytic capacitor's capacity will drop due to deterioration. To prevent secondary damage due to
capacitor's faults, Mitsubishi recommends the electrolytic capacitor to be replaced approx. every five years
even when used in a normal environment. Contact the Service Center for replacements.
Never perform a megger test (measure the insulation resistance) of the drive unit. Failure to observe this
could lead to faults.
Do not replace parts or devices while the power is ON.
Do not short-circuit, charge, overheat, incinerate or disassemble the battery.
There may be a unit filled with substitute Freon in the heat radiating fins of the 37kW or smaller unit. Be
careful not to break the heat radiating fins during maintenance or replacement.
Connect the encoder (CN2/CN3) immediately after the installation of the servo drive unit. In addition, when
a battery box is used, immediately connect to the BTA/BTB connector. (prevention of absolute position data
lost)
Replace the batteries with new ones immediately after the battery voltage drop alarm (9F) has been output.
Replace the batteries while applying the drive unit's control power.
Replace the batteries with new ones that are in their recommended use period.
Wrong connection may cause liquid leakage, heat generation and/or explosion.
Do not mix new batteries with used ones or mix different types of batteries.
CAUTION
Shut off with motor
brake control output
Motor
Electro-
magnetic
brake
CAUTION
Shut off with CNC brake
control PLC output
MBR EMG
24VDC