Delta MS300 Series User Manual page 17

Chapter 1 IntroductionMS300
suppression. If in doubt, install an extra electrostatic shielded cable on the power supply side
between the main circuit and the control terminals to increase shielding.
Asymmetric Ground System (Corner Grounded TN Systems)
Caution: Do not remove the RFI jumper while power to the input terminal of the drive is ON.
In the following four situations, you must remove the RFI jumper. This is to prevent the system from
grounding through the RFI and filter capacitors and damaging the drive.
You must remove the RFI jumper for an asymmetric ground system
1. Grounding at a corner in a triangle configuration
Figure 1-9
3. Grounding at one end in a single-phase
configuration
Figure 1-11
You can use the RFI jumper for a symmetrical grounding power system
In a situation with a symmetrical grounding power system, you
can use the RFI jumper to maintain the effect of the built-in EMC
filter and surge absorber. For example, the diagram on the right
is a symmetrical grounding power system.
2. Grounding at a midpoint in a polygonal
configuration
L 1
L 2
L 3
4. No stable neutral grounding in a three-phase
autotransformer configuration
L 1
N
8
Figure 1-10
L 1
L 2
L 3
Figure 1-12
Figure 1-13
L 1
L 2
L 3
L 1
L 2
L 3