Delta VFD300C43S-HS User Manual page 13

1-5 RFI Jumper
(1) In the drive there are Varistor / MOVs, which are connected from phase to phase and from phase to
ground, to protect the drive against mains surges or voltage spikes.
Because the Varistors / MOVs from phase to ground are connected to ground via the RFI jumper, the
protection will be ineffective when the RFI jumper is removed.
(2) In the models with built-in EMC filter the RFI jumper connects the filter capacitors to ground from a
return path for high frequency noise to isolate the noise from contaminating the mains power.
Removing the RFI jumper strongly reduces the effect of the built-in EMC filter. Although a single drive
complies with the international standards for leakage current, an installation with several drives with
built-in EMC filter can trigger the RCD. Removing the RFI jumper helps, but the EMC performance of
each drive would be no longer guaranteed.
Frame D0–H
Remove the MOV-PLATE by hands, no screws need to be loosen.
Isolating main power from ground:
When the power distribution system of the drive is a floating ground system (IT Systems) or an asymmetric
ground system (Corner Grounded TN Systems), you must remove the RFI jumper. Removing the RFI
jumper disconnects the internal capacitors from ground to avoid damaging the internal circuits and to
reduce the ground leakage current.
Important points regarding ground connection
 To ensure the safety of personnel, proper operation, and to reduce electromagnetic radiation, you must
properly ground the drive during installation.
 The diameter of the cables must comply with the local safety regulations.
 The shield of shielded cables must be connected to the ground of the drive to meet safety regulations.
 The shield of shielded power cables can only be used as the ground for equipment when the
aforementioned points are met.
 When installing more drives, do not connect the grounds of the drives in series but connect each drive
to ground. The following pictures show the correct and wrong ways to connect the grounds.
Figure 1-4
1-5
Chapter 1 IntroductionC2000-HS