Omron OMNUC U Series User Manual page 54

System Design and Installation
Be sure that no gaps are created when installing the cover, as can be cause by distortion when tighten-
ing screws.
Case
Case (inside)
j Selecting Components
No-fuse Breakers (MCCB)
When selecting no-fuse breakers, take into consideration the maximum output current and the inrush
current. The momentary maximum output for a servo system is approximately three times that of the
rated output, and a maximum output of three seconds can be executed. Therefore, select no-fuse
breakers with an operating time of at least five seconds at 300% of the rated maximum output. General-
purpose and low-speed no-fuse breakers are generally suitable. Refer to the table in 2-2-3 Terminal
Block W iring for the power supply input currents for each motor, and then add the current consumption
for the number of shafts, other controllers, etc., to make the selection.
The Servo Driver inrush current flows at a maximum of 50 A for 20 ms when 200 V is input. With low-
speed no-fuse breakers, a inrush current 7 to 8 times the rated current flows for 0.1 second. When mak-
ing the selection, take into consideration the entire inrush current for the system.
Surge Absorbers
Use surge absorbers to absorb surges from power supply input lines due to lightning, abnormal volt-
ages, etc. When selecting surge absorbers, take into account the varistor voltage, the amount of surge
immunity, and the amount of energy resistance. For 200-VAC systems, use a varistor voltage of 470 V.
The surge absorbers shown in the following table are recommended.
2-36
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Control panel
Oil-proof
packing
Conductive
packing
Case
Conductive
Oil-proof
packing
packing
Chapter 2
Cover