Operating the Drive
890CS Common Bus Supply - Frames B & D; 890CD Common Bus Drive and 890SD Standalone Drive - Frames B, C & D
Page
7-43
8
9
10
11
A
B
C
D
1
2
3
4
5
6
7
E
3-Phase Choke Sizing
One of the benefits of the 890 4-Q Regen drive is the reduction in the levels of harmonic currents drawn
from the supply. The total harmonic distortion (THD) of the mains current is related to the PWM switching
frequency, the supply voltage, the supply frequency and the inductance of the 3-phase line choke. The
maximum allowed PWM carrier frequency in non-overload conditions, for each frame size is given below:
890 Frame Size
PWM Carrier
Frequency
B to F
3kHz
G and H
2.5kHz
J 2kHz
The IEEE 519 standard (IEEE Standard Practices and Requirements for Harmonic Control in Electrical
Power Systems ) requires a THD of current of 5%. The tables below show the recommended 3-phase line
chokes (5% and 3% in series) and expected THD of current for 400V and 230V drives.
The PWM switching produces high levels of harmonic current in the 3% chokes. It is essential to have these
properly rated to avoid significant overheating. Suitable chokes have been developed for Parker SSD Drives
and their Part Numbers are provided below.