Selection Of Transformer - Danfoss VLT AFE 302 Operating Instructions Manual

Crane System Design
NOTE
The fan runs for the following reasons:
1. AMA
2. DC Hold
3 3
3. Pre-Mag
4. The frequency converter current exceeds 60% of
the its nominal current rating.
5. The heat sink temperature exceeds its limit. The
limit depends on the power size.
Once the fan is started it will run for minimum 10min.
External ducts
If additional duct work is added externally to the Rittal
cabinet the pressure drop in the ducting must be calculated.
Use the charts below to derate the frequency converter
according to the pressure drop.
(%)
90
80
70
60
50
40
30
20
10
0
0 0.5
Illustration 3.1 D frame derating vs. pressure change
frequency converter air flow: 450cfm (765m
(%)
90
80
70
60
50
40
30
20
10
0
0 0
Illustration 3.2 E frame derating vs. pressure change (small fan),
P250T5 and P355T7-P400T7
frequency converter air flow: 650cfm (1105m
10
4.9 13 27.3 45.9 66 89.3
Pressure Increase
3 /h)
0.1 3.6 9.8 21.5 43.4 76 147.1
Pressure Change
3 /h)
MG.33.X2.02 - VLT
®
VLT Active Front End AFE 302 Operating Instructions Liebherr
(%)
90
80
70
60
50
40
30
20
10
0
0
Illustration 3.3 E frame derating vs. pressure change (large fan),
P315T5-P400T5 and P500T7-P560T7
frequency converter air flow: 850cfm (1445m
(%)
90
80
70
60
50
40
30
20
10
0
0
115.7 147
(Pa) Illustration 3.4 F1, F2, F3, F4 frame derating vs. pressure change
frequency converter air flow: 580cfm (985m

3.1.9 Selection of Transformer

•
•
NOTE
Danfoss will review/evaluate the LCL filter design for each
237.5 278.9
application, especially with a new transformer used.
(Pa)
®
is a registered Danfoss trademark
0.2 0.6 2.2 5.8 11.4 18.1 30.8
Pressure Change
25 50 75 100 125 150
Pressure Change
The output of the HT-transformer must be
specified for 630V.
It is recommended to use 2 separate transformers
for 630V and the 400V and these transformers
should be physically separated. The 400V
transformer must be close to or in the E-house to
have a short ground cable.
69.5 152.8 210.8
(Pa)
3
/h)
175 200 225
3
/h)