Danfoss VLT AQUA FC 202 Design Guide

10.12 Eciency
Eciency of the drive (n
VLT
)
The load on the drive has little eect on its eciency. In general, the eciency is the same at the rated motor frequency f
M,N,
even if
the motor supplies 100% of the rated shaft torque or only 75%, for example if there are part loads. This also means that the ecien-
cy of the drive does not change even if other U/f characteristics are selected. However, the U/f characteristics inuence the ecien-
cy of the motor. The eciency declines a little when the switching frequency is set to a value of above 5 kHz. The eciency is also
slightly reduced if the mains voltage is 480 V, or if the motor cable is longer than 30 m (98 ft).
Drive eciency calculation
Calculate the eciency of the drive at dierent speeds and loads based on the graph in Illustration 79. Multiply the factor in this
graph by the specic eciency factor listed in the specication tables in :
e30bd198.10
1
0% 50% 100% 150% 200%
100% Load
75% Load
50% Load
25% Load
1.02
Relative efficiency
0.98
0.96
0.94
0.92
0.9
% speed
Illustration 79: Typical Eciency Curves
Example: Assume a 160 kW, 380–480/500 V AC drive at 25% load at 50% speed. The graph shows 0.97 - the rated eciency for a
160 kW drive is 0.98. The actual eciency is then: 0.97x0.98=0.95.
The MyDrive
®
ecoSmart
™
tool helps to calculate the eciency, refer to www.ecosmart.danfoss.com.
Eciency of the motor (η
MOTOR
)
The eciency of a motor connected to the drive depends on the magnetizing level. In general, the eciency is as good as with
mains operation. The eciency of the motor depends on the type of motor. In the range of 75–100% of the rated torque, the e-
ciency of the motor is practically constant, both when the drive runs the motor and when it runs directly on mains. In small motors,
the inuence from the U/f characteristic on eciency is marginal. However, in motors from 11 kW (15 hp) and up, the advantages
are signicant. Typically, the switching frequency does not aect the eciency of small motors. Motors from 11 kW (15 hp) and up
have their eciency improved (1–2%) because the shape of the motor current sine-wave is almost perfect at high switching fre-
quency.
Eciency of the system (η
SYSTEM
)
To calculate the system eciency, the eciency of the drive (η
VLT
) is multiplied by the eciency of the motor (η
MOTOR
):
η
SYSTEM
= η
VLT
x η
MOTOR
10.13 Acoustic Noise and Airow
Table 89: Acoustic Noise Ratings
Enclosure size
50% fan speed [dBA]
(1)
Full fan speed [dBA]
(1)
A1
51
60
A2
51
60
A3
51
60
A4
51
60
A5
54
63
B1
61
67
B2
58
70
B4
52
62
C1
52
62
AJ300847815559en-000101 / 130R0337144 | Danfoss A/S © 2020.09
Electrical Installation
Considerations
VLT® AQUA Drive FC 202
Design Guide

Danfoss VLT AQUA FC 202 Specifications

General

Brand	Danfoss
Model	VLT AQUA FC 202
Category	DC Drives
Language	English