Delta CT2000 Series User Manual page 7

Chapter 1 IntroductionCT2000 Series
Main power isolated from earth:
When the power distribution system of the AC motor drive is a floating ground system (IT) or an
asymmetric ground system (TN), the RFI jumper must be removed. After removing RFI jumper, cuts off
the internal RFI capacitor (filter capacitor) between the system's frame and the central circuits to avoid
damaging the central circuits and (according to IEC 61800-3) reduce the ground leakage current.
Important points regarding ground connection
 To ensure the safety of personnel, proper operation, and to reduce electromagnetic radiation, the AC
motor drive must be properly grounded during installation.
 The diameter of the cables must meet the size specified by safety regulations.
 The earthing cable must be connected to the ground of the AC motor drive to meet safety regulations.
 The earthing cable can only be used as the ground for equipment when the aforementioned points are
met.
 When installing multiple sets of AC motor drive, do not connect the grounds of the AC motor drive in
series. As shown below
Pay particular attention to the following points:
 After turning on the main power, do not remove the RFI jumper while the power is on.
 Make sure the main power is turned off before removing the RFI jumper.
 Removing the RFI jumper will also cut off the conductivity of the capacitor. Gap discharge may occur
once the transient voltage exceeds 1000V.
If the RFI jumper is removed, there will no longer be reliable electrical isolation. In other words, all
controlled input and outputs can only be seen as low-voltage terminals with basic electrical isolation. Also,
when the internal RFI capacitor is cut off, the AC motor drive will no longer be electromagnetic
compatible.
 The RFI jumper may not be removed if the main power is a grounded power system.
 The RFI jumper may not be removed while conducting high voltage tests. When conducting a high
voltage test to the entire facility, the main power and the motor must be disconnected if leakage
current is too high.
Floating Ground System(IT Systems)
A floating ground system is also called IT system, ungrounded system, or high impedance/resistance
(greater than 30Ω) grounding system.
Disconnect the ground cable from the internal EMC filter.

In situations where EMC is required, check whether there is excess electromagnetic radiation

affecting nearby low-voltage circuits. In some situations, the adapter and cable naturally provide
Ground terminal
Best wiring setup for ground wires
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