Rockwell Automation 8520 9/Series Hardware TAB 5 - Manual (Page 134)

Section 5B
9/440HR CNC/Drive System
5B-60
Grounded Power Configuration
As shown in Figure 5B.46, the grounded power configuration allows you
to ground your 3–phase power at a neutral point. Each 1394 system
module has a factory–installed jumper configured for grounded power
distribution. If you determine that you have grounded power distribution
in your plant you do not need to modify your system. For detailed
information about 1394 grounded power configuration, refer to your 1394
Digital AC Multi-Axis Motion Control System Users Manual (publication
1394-5.0).
Figure 5B.46
Grounded Power Configuration
Ungrounded Power Configuration
As shown in Figure 5B.47, the ungrounded power configuration does not
allow for a neutral ground point. If you determine that you have
ungrounded power distribution in your plant, you need to move the
factory–installed jumper to the ungrounded power distribution position to
prevent electrostatic buildup inside the 1394. Refer to the ground jumper
procedures for the system module you need to configure.