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4   System Design
OMNUC G5-series (Pulse-train Input Type) AC Servomotors and Servo Drives User’s Manual
4-1  Installation Conditions
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4-1-2  Servomotor Installation Conditions
Use the Servomotor with an oil seal if you are using it in an environment where oil drops can adhere to 
the through-shaft part. The operating conditions of the Servomotor with an oil seal are as follows:
• Keep the oil level below the lip of the oil seal.
• Prepare a good lubricated condition under which only oil droplets splash on the oil seal.
• If you are using the Servomotor with the shaft in upward direction, make sure that no oil accumulates 
on the lip of the oil seal.
• When you mount a Servomotor onto a small device, be sure to provide enough radiation space on 
the mounting area. Otherwise the Servomotor temperature rises too high. One of the preventive 
measures is to install a radiator plate between the motor attachment area and the motor flange. (See 
below.) 
Failure to follow this guideline may result in damaging the Servomotor due to a temperature rise. 
Refer to 3-3 Servomotor Specifications on page 3-36 for the radiator plate specifications.
• The temperature rise depends on the mounting part materials and the installation environment. 
Check the actual temperature rise by using a real Servomotor.
• Depending on the environment, such as when the Servomotor is installed near a heating element, 
the Servomotor temperature may rise significantly. In this case, take any of the following measures.
• Lower the load ratio.
• Review the heat radiation conditions of the Servomotor.
• Install a cooling fan and apply forced air cooling to the Servomotor.
• Take measures to protect the motor shaft from corrosion.
The motor shaft is coated with anti-corrosion oil when shipped, but anti-corrosion oil or grease should 
also be applied when connecting the components that apply load to the shaft.
Oil-water Measures
Radiator Plate Installation Conditions
Other Precautions
Never repair the Servo Drive by disassembling it. 
Electric shock or injury may result.
Do not apply a commercial power supply directly to the motor. 
Fire may result.
Radiator plate
Caution