Calculation Example - Danfoss VLT AHF 005 Design Manual

Basic Operating Principle o...
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 [%]
0.278 100
1.29 100
7.94 100
56.9 100
245 100
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 =44 A.
out,VLT
•
Cos phi=0.85.
•
f [%]=25 Hz, resulting in 50%.
motor
•
load [%]=33 A, resulting in 75% (33 A/44 A x
motor
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 =I x cos(phi) x f
In,VLT out,VLT motor
I =44 x 0.85 x 0.50 x 0.75 x 1.02=14.3 A
In,VLT
Calculating the AHF input current
I =I =14.3 A
In,AHF In,VLT
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
operation load using 2-dimensional interpolation
OPT
•
Loss =177 W.
2
•
Loss =127 W.
1
•
Load =20 A.
2
•
Load =10 A.
1
•
Load = Load = Load of AHF in point of
OPT AHF
operation = 14.3 A.
MG80C502
Design Guide
Cosine phi
0.73
0.79
0.85
0.86
0.87
®
[%] x load [%] x 1.02
motor
, in AHF point of
OPT
Danfoss A/S © 10/2016 All rights reserved.
•
Loss = Loss = Loss in AHF in point of
OPT AHF
operation.
Loss [W]
Loss
2
177 W
Loss
OPT
Loss
1
127 W
Load Load
1 OPT
10 A 14.3 A
Illustration 3.13 Determining Power Loss with 2-dimensional
Interpolation
Loss = Loss + (Loss - Loss
OPT 1 2
(Load – Load ))
2 1
Loss = Loss = 127 + (177 - 127) x ((14.3 - 10) / (20 -
OPT AHF
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 = 370 W.
VLT
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 = Loss + Loss = 149 W + 370 W = 519 W
CDM AHF VLT
Load Load [A]
2
20 A
) x ((Load – Load ) /
1 OPT 1
®
19
3 3