The RMS value of line current is affected not only by Altivar size but also by harmonics.
In drives up to 22kW (up to D22N4/E), the charging current during ATV power-up is limited by a pre-charging resistor that is bypassed after charging the DC bus.
In drives above 22kW, there is no pre-charging resistor but there is a semi-controlled input rectifier (thyristor + diode bridge) and moreover built-in DC choke. This DC choke is responsible for a significant drop in harmonics when comparing:
ATV340D22N4/E with THDi above 100% in HD (at 400V/50Hz)
ATV350D30N4E with THDi below 48% (at 400V/50Hz)
To express the exact ratio between ATV340D30N4E and ATV340D22N4(E) line current look at attached file.
In drives up to 22kW (up to D22N4/E), the charging current during ATV power-up is limited by a pre-charging resistor that is bypassed after charging the DC bus.
In drives above 22kW, there is no pre-charging resistor but there is a semi-controlled input rectifier (thyristor + diode bridge) and moreover built-in DC choke. This DC choke is responsible for a significant drop in harmonics when comparing:
ATV340D22N4/E with THDi above 100% in HD (at 400V/50Hz)
ATV350D30N4E with THDi below 48% (at 400V/50Hz)
To express the exact ratio between ATV340D30N4E and ATV340D22N4(E) line current look at attached file.
Опубликовано для:Schneider Electric Казахстан
