Danfoss VLT AHF 005, Руководство по конструкции

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The EN 50598 standard for Ecodesign of Power Drive
Systems allows the use of reference values. Determine the
motor cosine phi value by the motor nominal power rating
as kVA and with linear interpolation from the reference
values in
Table 3.2 .
Nominal power [kVA] Current [%] Cosine phi
0.278 100 0.73
1.29 100 0.79
7.94 100 0.85
56.9 100 0.86
245 100 0.87
Table 3.2 Motor Reference Values from EN 50598
3.2.6.1 Calculation Example
The frequency converter used in the example is a VLT
®
AutomationDrive FC 302, T5, 22 kW with Class A1/B RFI
filter and enclosure protection rating IP20.
Frequency converter values
•
I
out,VLT
=44 A.
•
Cos phi=0.85.
•
f
motor
[%]=25 Hz, resulting in 50%.
•
load
motor
[%]=33 A, resulting in 75% (33 A/44 A x
100).
In the example, VLT
®
Advanced Harmonic Filter AHF 010
with ordering number 130B1111 is selected as filter. See
Table 5.3 for further specifications of the filter.
AHF values
•
40 A nominal current.
•
AHF 010, THDi = 10%.
•
IP20.
Calculating the frequency converter input current
I
In,VLT
=I
out,VLT
x cos(phi) x f
motor
[%] x load
motor
[%] x 1.02
I
In,VLT
=44 x 0.85 x 0.50 x 0.75 x 1.02=14.3 A
Calculating the AHF input current
I
In,AHF
=I
In,VLT
=14.3 A
Calculating the power loss
Matching values from Table 9.2
•
127 W power loss at 10 A current loading.
•
177 W power loss at 20 A current loading.
Determining the power loss, Loss
OPT
, in AHF point of
operation load
OPT
using 2-dimensional interpolation
•
Loss
2
=177 W.
•
Loss
1
=127 W.
•
Load
2
=20 A.
•
Load
1
=10 A.
•
Load
OPT
= Load
AHF
= Load of AHF in point of
operation = 14.3 A.
•
Loss
OPT
= Loss
AHF
= Loss in AHF in point of
operation.
Loss [W]
Loss
2
177 W
Loss
OPT
Loss
1
127 W
Load
1
10 A
Load
OPT
14.3 A
Load
2
20 A
Load [A]
130BE895.10
Illustration 3.13 Determining Power Loss with 2-dimensional
Interpolation
Loss
OPT
= Loss
1
+ (Loss
2
- Loss
1
) x ((Load
OPT
– Load
1
) /
(Load
2
– Load
1
))
Loss
OPT
= Loss
AHF
= 127 + (177 - 127) x ((14.3 - 10) / (20 -
10)) = 149 W
The power loss of the frequency converter provided by
VLT
®
ecoSmart:
•
Power loss @ 50% motor frequency and 50%
motor current = 249 W.
•
Power loss @ 50% motor frequency and 100%
motor current = 490 W.
The power loss of the frequency converter at 50% motor
frequency and 75% torque-producing current are found by
2-dimensional interpolation as 370 W.
Loss
VLT
= 370 W.
Alternatively, identify the power loss of the frequency
converter by entering the point of operation in VLT
®
ecoSmart as a user-defined operating point.
To determine the power loss of the CDM, sum up the
power losses in the operating point of the AHF and the
frequency converter:
Loss
CDM
= Loss
AHF
+ Loss
VLT
= 149 W + 370 W = 519 W
Basic Operating Principle o... Design Guide
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