Danfoss VLT 2800 Design Guide

Typical values for the rise time and peak voltage U
PEAK
are
measured on the motor terminals between 2 phases.
To obtain approximate values for cable lengths and
voltages not mentioned below, use the general principle:
1. Rise time increases/decreases proportionally with cable
length.
2. U
PEAK
= DC-link voltage x 1.9
(DC-link voltage = Mains voltage x 1.35).
3.
dU / dt =
0.5 × U
PEAK
Risetime
Data are measured according to IEC 60034-17.
Cable
length[m]
Mains
voltage[
V]
Rise time
[μs]
Peak
voltage[V
]
dU/dt
V/[μs]
5 220 0.137 348 2.116
42 220 0.362 460 1.016
5 240 0.129 365 2.294
42 240 0.310 498 1.303
Table 5.1 VLT 2803-2815
Cable
length[m]
Mains
voltage[
V]
Rise time
[μs]
Peak
voltage[V
]
dU/dt
V/[μs]
5 380 0.081 680 6716
15 380 0.167 960 4593
30 380 0.306 992 2593
5 480 0.086 840 7778
15 480 0.177 1168 5279
30 480 0.323 1232 3050
Table 5.2 VLT 2805-2840
Cable
length[m]
Mains
voltage[
V]
Rise time
[μs]
Peak
voltage[V
]
dU/dt
V/[μs]
5 380 0.120 772 4438
40 380 0.188 1004 3482
78 380 0.220 1012 2854
5 480 0.120 920 4667
40 480 0.245 1252 3646
78 480 0.225 1220 3168
Table 5.3 VLT 2805-2840
5.1.7
Acoustic Noise
The acoustic noise from the frequency converter comes
from 2 sources:
•
DC intermediate circuit coils.
•
Integral fan.
Below are the typical values measured at a distance of 1 m
from the unit at full load:
•
VLT 2803-2815 1x220 V: 52 dB(A).
•
VLT 2822 1x220 V PD2: 54 dB(A).
•
VLT 2840 1x220 V PD2: 55 dB (A).
•
VLT 2840 3x200 V PT2: 54 dB (A).
•
VLT 2803-2822 3x220 V: 52 dB(A).
•
VLT 2805-2840 3x400 V: 52 dB(A).
•
VLT 2855-2875 3x400 V: 54 dB(A).
•
VLT 2880-2882 3x400 V: 55 dB(A).
5.1.8
Derating for Ambient Temperature
The ambient temperature (T
AMB,MAX
) is the maximum
temperature allowed. The average (T
AMB,AVG
) measured over
24 hours, must be at least 5 °C lower. If the frequency
converter operates at temperatures above 45 °C, a derating
of the rated output current is necessary.
Illustration 5.1 Derating for Ambient Temperature
5.1.9
Temperature-Dependent Switching
Frequency
This function ensures the highest possible switching
frequency without the frequency converter becoming
thermally overloaded. The internal temperature is the
actual expression of the degree to which the switching
frequency can achieve based on the load, the ambient
temperature, the supply voltage and the cable length.
All about VLT 2800
Design Guide
MG27E402 Danfoss A/S © Rev. May/2014 All rights reserved. 129
5 5

Danfoss VLT 2800 Specifications

General

Brand	Danfoss
Model	VLT 2800
Category	DC Drives
Language	English