Omron OMNUC G User Manual page 129

Precautions
for Correct Use
R88M-G4K510
4.5 kW (Without Oil Seal)
Without brake
Rated Torque (%)
With brake
100%
0 10 20 30 40
Temperature Characteristics of the Servomotor and Mechanical System
OMNUC G-Series AC Servomotors use rare earth magnets (neodymium-iron magnets).
The temperature coefficient for these magnets is approximately −0.13%/
drops, the Servomotor's maximum momentary torque increases, and as the temperature rises, the
Servomotor's maximum momentary torque decreases.
The maximum momentary torque rises by 4% at a normal temperature of 20
temperature of −10
Conversely, the maximum momentary torque decreases about 8% when the magnet warms up to
°
80 C from the normal temperature.
Generally, when the temperature drops in a mechanical system, the friction torque and the load
torque increase.
For that reason, overloading may occur at low temperatures. In particular, in systems that use a
Decelerator, the load torque at low temperatures may be nearly twice as much as the load torque
at normal temperatures.
Check whether overloading may occur at low temperature startup.
Also check to see whether abnormal Servomotor overheating or alarms occur at high
temperatures.
An increase in load friction torque seemingly increases load inertia.
Therefore, even if the Servo Drive gains are adjusted at a normal temperature, the Servomotor
may not operate properly at low temperatures.
Check to see whether there is optimal operation even at low temperatures.
Use the following Servomotors in the ranges shown in the graphs below.
Using outside of these ranges may cause the Servomotor to generate
heat, which could result in encoder malfunction.
R88M-G6K010T
6 kW (With Oil Seal)
Rated Torque (%)
100%
85%
70%
Ambient
temperature
0 10 20
°
C.
3-2 Servomotor Specifications
Without brake
With brake
90%
85%
Ambient
temperature
30 40
°
C. As the temperature
°
C compared to a
3-30
3