3Ph du/dt output inductor 3x400V 50Hz; 90A; 0.065mH

dU/dt output chokes (also known as output chokes or du/dt filters) are installed downstream of frequency converters or pulse inverters, i.e. between the converter and the motor.

They are designed to limit the rate of voltage rise (du/dt) at the motor output.

'du/dt' means: the change in voltage over time (in V/µs).

Frequency converters generate steep-edged PWM voltages (pulse width modulation), which cause very rapid voltage rises.

With long motor cables or sensitive motor windings, these steep voltage peaks can:

Generate overvoltages at the motor terminals (due to reflections in the cable),

Cause insulation damage to the motor windings,

Cause bearing currents and electromagnetic interference (EMC problems),

Significantly shorten the service life of the motor.

Use of choke or sine wave filter:

for cable lengths <5m: du/dt filter

for cable lengths 5-20m: du/dt choke

for cable lengths >20m: sine wave filter