Filter Selection; What This Chapter Contains; Output Voltage Of The Drive; Graphs - ABB ACS800 Hardware Manual

Filter selection

What this chapter contains

The chapter advises on selecting the appropriate du/dt filter for the drive.

Output voltage of the drive

The output voltage waveform of an IGBT inverter generates voltage spikes higher
than the intermediate circuit DC voltage of the drive at the motor terminals. The
voltage spikes with the high du/dt values of the inverter can cause additional stress
on the motor and motor cable insulation. This may shorten the motor life. Optional
ABB du/dt filters protect the motor insulation system.

Graphs

The graphs below show the peak line-to-line voltage (Û
dt) at the motor terminals as a function of the motor cable length. Û
scaled to the nominal line-to-line voltage (U
value in volts and du/dt value in volts per microsecond, multiply the values of the
graph by the supply voltage (U
The values in the first graph are measured with an ABB du/dt filter while the second
graph without any output filtering. The values in the second graph are only
representative. The actual unfiltered du/dt values depend on the ACS800 drive type,
and are usually in the range of 1 to 5 kV/microsecond.
In case of drives with an IGBT supply unit or resistor braking, the Û
values are approximately 20% higher.
The voltage rise time can be calculated as follows: t = 0.8 · Û
). To calculate the actual peak voltage
N
).
N
) and voltage change (du/
LL
and du/dt are
LL
and du/dt
LL
/(du/dt).
LL
Filter selection
9