Delta CT2000 Series, User Manual

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Chapter 19 EMC Standard Installation Guide

CT2000 Series
19-17
AC Motor Drives with Built-in Filter
1.
Since interferences are suppressed by installing an earthed capacitor in the filter, the amount of current to
ground (leakage current) could result in electric shocks to personnel or the power system. Please be aware of
this problem.
2.
Since the leakage current to ground can be high, it is crucial to implement protective earthing to prevent
electrical shocks.
Filter Installation (With and Without)
Zero Phase Reactor (Choke)
Interferences can also be suppressed by installing a zero phase reactor at the power supply side and/or the
AC Motor Drive’s output, depending on where the interference is. Since currents are large at the power input and
the AC Motor Drive’s output, please carefully select the magnetic core with suitable current handling capability. An
ideal magnetic material for large currents is compound magnetic powder. It has a higher current handling capability
and higher impedance compared to pure metallic magnetic cores. It is therefore suitable to implement in a high
frequency environment. The impedance can also be enhanced by increasing the turn ratio.
Zero Phase Reactor Installation
There are two installation methods, depending on the size of the zero phase reactor and the motor cable length.
1. Wind the motor cable through the middle of a zero-phase reactor 4 times. Place the reactor and the AC Motor
Drive as close to each other as possible.
Power
Supply
Zero Phase Reactor
MOTOR
U/T1
V/T2
W/T3
R/L1
S/L2
T/L3
2. Place all wires through the middle of four zero-phase reactors without winding.
U/T1
V/T2
W/T3
R/L1
S/L2
T/L3
Power
Supply
Zero Phase Reactor
MOTOR
Analog Input Signals
If the analog input signals are affected by noise from the AC motor drive, please connect a capacitor and a
ferrite core as indicated in the following diagram.
Wind the wires around the core in same direction for 3 times or more.