Switching Frequency Filter - Control Techniques Unidrive Regen Installation Manual

5.6

Switching frequency filter

The AC input terminals of a Regen drive produce a PWM output voltage, which has a sinusoidal component at line frequency, plus significant
harmonics at the switching frequency and its multiples.
This filter prevents switching frequency harmonic currents getting back into the supply. If the filter is not fitted, the presence of currents in the kHz
region could cause supply problems or disturbance to other equipment.
N
NOTE
The switching frequency filter inductors need to be rated to the total current requirement.
The following inductors are standard 3-phase inductors (rated at drive rated current for a single Regen system or rated at total current requirement for
multiple Regen system), they carry only 50/60Hz current with a negligible amount of high frequency current.
The capacitors specified below are suitable for operation at any switching frequency. These capacitors are sized for operation at 3kHz however
operation above 3kHz is possible with the capacitors being more effective.
Table 5-6 Switching frequency filter
Drive
Rated
current
Model
A
UNI 1405 9.5
UNI 2401 12
UNI 2402 16
UNI 2403 25
UNI 3401 34
UNI 3402 40
UNI 3403 46
UNI 3404 60
UNI 3405 70
UNI 4401 96
UNI 4402 124
UNI 4403 156
UNI 4404 180
UNI 4405 202
UNI 5401 300
UNI 5402 600
UNI 5403 900
UNI 5404 1200
UNI 540 300 x
X X
= number of size 5 drives
X
5.6.1 Protection
An MCB should be fitted between the AC supply and the capacitor. This is to protect the wiring between the capacitor and the main bus bar.
N
NOTE
For multiple Regen systems, refer to Appendix B Component sizing calculations on page 36 for sizing of the MCB.
12
3-phase inductor
Lfilt
CT part
number
mH
3.160 4401-0162
2.500 4401-0163
1.875 4401-0164
1.200 4401-0165
0.880 4401-0166
0.750 4401-0167
0.650 4401-0168
0.500 4401-0169
0.390 4401-0170
0.315 4401-0171
0.240 4401-0172
0.190 4401-0173
0.165 4401-0174
0.135 4401-0175
0.100 4401-0176
0.050 4401-0177
0.034 4401-0178
0.025 4401-0179
0.100 /
X
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3-phase capacitor
Cfilt
CT part
number
µF
5.7 1610 - 5752
24 1665 - 2244
48 1665 - 2484
80 (x1)
80 (x2)
80 (x3) 1665 - 2804
capacitor
80 (x4)
80 (x )
X
MCB rating
rms Peak
current current
A A
28
31
2.1
36
45
106
115
15 124
142
160
252
262
25 325
348
385
580
580
35 per
580
580
580
Unidrive Regen Installation Guide
Issue Number: 2