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10   Troubleshooting and Maintenance
OMNUC G5-series (Pulse-train Input Type) AC Servomotors and Servo Drives User’s Manual
10-5  Periodic Maintenance
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10-5-1  Servomotor Life Expectancy
10-5 Periodic Maintenance
Servomotors and Servo Drives contain many components and will operate properly only when each of 
the individual components is operating properly. 
Some of the electrical and mechanical components require maintenance depending on application 
conditions. Periodic inspection and replacement are necessary to ensure proper long-term operation of 
Servomotors and Servo Drives. (Quoted from The Recommendation for Periodic Maintenance of a 
General-purpose Inverter published by JEMA.)
The periodic maintenance cycle depends on the installation environment and application conditions of 
the Servomotors and Servo Drives. 
Recommended maintenance times are given below for Servomotors and Servo Drives. Use these for 
reference in periodic maintenance.
• The lifetimes for the different motor parts are listed below.
Bearings: 20,000 hours
Decelerator: 20,000 hours
Oil seal: 5,000 hours
Encoder: 30,000 hours
These values assume a motor operating ambient temperature of 40°C, a shaft load within the 
specified value, rated operation (rated torque and rated rotation speed), and proper installation as 
described in this manual.
The bearings, decelerator, oil seal, and encoder can be replaced for repair.
• The radial load during Servomotor operation on timing pulleys and other components contacting belts 
is two or more times the static load or more. Consult with the belt and pulley manufacturers and 
adjust designs and system settings so that the motor allowable axial load is not exceeded even 
during operation. If a motor is used under a shaft load exceeding the allowable limit, the motor shaft 
can break and the bearings can be damaged.
After replacing the Servo Drive, transfer to the new Servo Drive all data needed to resume 
operation, before restarting operation. 
Equipment damage may result.
Never repair the Servo Drive by disassembling it. 
Electric shock or injury may result.
10-5-1 Servomotor Life Expectancy
Caution