Analog Input Signals; Harmonic Interference; Harmonic Current At The Power Supply Side; Suppression Of Harmonic Currents & Ac Reactor - Delta C2000 series User Manual

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.
5.2

Harmonic Interference

The AC motor drive's input current is non-linear, the input rectifier generates harmonics. Harmonics must
be limited to within a certain range to avoid impact the mains power and to avoid current distortion to
ensure surrounding devices are not influenced. An AC Motor Drive with built-in DC reactor suppresses
harmonic currents (Total Harmonic Current Distortion THID) effectively and therefore reduces the
harmonic voltage peaks (Total Harmonic Voltage Distortion).

Harmonic Current at the Power Supply Side

Suppression of Harmonic Currents
When a large portion of lower order harmonic currents (5
surrounding devices will be disturbed and the power factor will be low as a result of reactive power.
Installing a reactor at the AC Motor Drive's input effectively suppresses lower order harmonic currents.
AC Reactor
Installed in series with the power supply and is effective in reducing low order current harmonics.
Features of an AC reactor include:
1. Reduces the harmonic currents to the AC Motor Drive and increases the impedance of the power
supply.
2. Absorbs interferences generated by surrounding devices (such as surge voltages, currents, and
mains surge voltages) and reduce their effect on the AC Motor Drive.
3. Increases the power factor.
C
Ferrite core
(A) Fund amen tal Sin e Wa ve
(6 0Hz)
(B) Ha rmo nic
r d
3
(1 80H z)
(C) H armo nica lly
Di sto rte d Wa ve
AVI/ACI/AUI
ACM
th th th ,
, 7 , 11 etc) occur at the power input,
14
(A) Fund amen tal Sin e Wa ve
(6 0Hz)
(B) Ha rmon ic
th
5
(3 00H z)
(C) H armo ni ca lly
Di sto rted Wa ve