Rfi Jumper Location; Rfi Jumper; Isolating Main Power From Ground; Important Points Regarding Ground Connection - Delta VFD-EL-W Series User Manual

RFI Jumper Location

NOTE
If it is required by the grounding system or the current leakage is too big and causes tripping, you can
remove RFI jumper which is near the input terminals (R/L1, S/L2, T/L3) by loosing screws. Once you
remove the RFI jumper, retighten the screws to keep good grounding to prevent electric shock.
Frame Power Range
0.25 - 1hp
A1
(0.2 - 0.75kW)
A2
2 HP (1.5 kW)
B 2–5.5 HP (1.5–4 kW)

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 filer capacitors to ground to form a return
path for high frequency noise to isolate the noise from contaminating the main power. Removing the RFI
jumper strongly reduces the effect of the built-in EMC filter.

Isolating main power from ground:

When the power distribution system for the motor drive is a floating ground system (IT) or an asymmetric
ground system (TN), 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


Do not remove RFI jumper while the power is ON.

Make sure that main power is OFF before removing the RFI jumper.

Removing the RFI jumper also cuts off the built-in EMC filter capacitors. Compliance with the EMC
specifications is no longer guaranteed.
If you remove the RFI jumper, you remove the reliable electrical isolation. In other words, all controlled inputs and
outputs become low-voltage terminals with basic electrical isolation. Also, when you remove the internal RFI
jumper, the motor drive is no longer electromagnetic compatible (EMC).

Do not remove the RFI jumper if the main power is a grounded power system to make EMC filter effective

You must remove the RFI jumper when conducting high voltage tests. When conducting a high voltage test for
the entire facility, disconnect the main power and the motor if the leakage current is too high.

To prevent damage to the drive, you must remove the RFI jumper connected to ground if the AC motor drive is
installed on an ungrounded power system or a high resistance-grounded (greater than 30 Ω) power system or a
corner grounded TN system.
VFD002EL21W(-1), VFD004EL21W(-1) / 43W(-1),
VFD007EL21W(-1) / 43W(-1),
VFD015EL43W(-1)
VFD015EL21W(-1), VFD022EL21W / 43W(-1), VFD040EL43W(-1)
RFI jumper
Grounding
Models
Chapter 1 Introduction VFD-EL-W

R/L1
S/L2
T/L3
1-5