Omron J7 series, User Manual

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25
Wiring
Chapter 2-2
Causes of Harmonics
Generation Usually, electric machines have built-in circuitry that converts commercial AC
power supply into DC power.
Such AC power, however, contains harmonics due to the difference in current
flow between DC and AC.
Obtaining DC from AC Using Rectifiers and Capacitors
DC voltage is obtained by converting AC voltage into a pulsating one-side
voltage with rectifiers and smoothing the pulsating one-side voltage with
capacitors. Such AC current, however, contains harmonics.
Inverter
The Inverter as well as normal electric machines has an input current
containing harmonics because the Inverter converts AC into DC. The output
current of the Inverter is comparatively high. Therefore, the ratio of harmonics
in the output current of the Inverter is higher than that of any other electric
machine.
Voltage
Voltage
Voltage
Current
Time
Rectified
Smoothed
Time
Time
Time
A current flows into the
capacitors. The current is
different from the voltage
in waveform.