Mains Input; General Requirements; Harmonics; Mains Configuration And Emc Effects - Danfoss VLT ISD 510 Design Manual

System Integration

4.4 Mains Input

4.4.1 General Requirements

Ensure that the supply has the following properties:
•
Grounded 3-phase mains network, 400–480 V AC
•
3-phase frequency: 47–63 Hz
•
3-phase lines and PE line
•
Mains supply: 400–480 V ±10%
•
Continuous input current SAB: 12.5 A
•
Intermittent input current SAB: 20 A
NOTICE
Use fuses and/or circuit breakers on the supply side of
the SAB to comply with CE or UL as detailed in
Table 4.10.
CE Compliance (IEC 60364)
Recommended Recommended
fuse size circuit breaker
gG-16 Eaton/Moller
PKZM0-16
Table 4.10 Fuses and Circuit Breakers
Maximum imbalance 3% of the rated supply voltage
temporary between
mains phase
True power factor [λ] ≥0.9 at rated current
Switching on input Maximum 2 times per minute
supply
•
Environment Overvoltage category III
according to
•
Pollution degree 2
EN60664-1
Mains drop out During low mains or a mains drop-out,
the SAB and the servo drives keep
running until the DC-link voltage drops
below 373 V. Full torque of the servo
drives cannot be expected at mains
voltage 10% below the rated supply
voltage.
Table 4.11 Additional Specifications

4.4.2 Harmonics

®
The VLT Integrated Servo Drive ISD 510 System takes up
non-sinusoidal current from the mains, which increases the
input current IRMS. A non-sinusoidal current is transformed
by means of a Fourier analysis and split up into sine-wave
MG36C102
Design Guide
UL Compliance
(NEC 2014)
Maximum Recommended
trip level maximum fuse
in [A] size
•
®
16
Littelfuse
KLSR015
•
®
Littelfuse
FLSR015
Danfoss A/S © 08/2017 All rights reserved.
currents with different frequencies, that is different
harmonic currents IN with 50 Hz as the basic frequency.
The harmonics do not affect the power consumption
directly, but increase the heat losses in the installation
(transformer, cables). Consequently, in plants with a high
percentage of rectifier load, maintain harmonic currents at
a low level to avoid overload of the transformer and high
temperature in the cables.
NOTICE
Some of the harmonic currents might disturb communi-
cation equipment connected to the same transformer or
cause resonance in connection with power factor
correction units.
To ensure low harmonic currents, the SAB is equipped with
intermediate circuit coils as standard. DC-coils reduce the
total harmonic distortion (THD) to 40%.
4.4.2.1 Mains Configuration and EMC
effects
Only TN mains systems are allowed for powering the VLT
Integrated Servo Drive ISD 510 System.
•
TN-S: A 5-wire system with separate neutral (N)
and protective earth (PE) conductors. It provides
the best EMC properties and avoids transmitting
interference.
•
TN-C: A 4-wire system with a common neutral
and protective earth (PE) conductor throughout
the system. The combined neutral and protective
earth conductor results in poor EMC character-
istics.
IT mains systems and AC mains systems with a grounded
mains are not allowed.

4.4.2.2 Mains Transients

Transients are brief voltage peaks in the range of a few
thousand volts. They can occur in all types of power distri-
bution systems, including industrial and residential
environments.
Lightning strikes are a common cause of transients.
However, they are also caused by switching large loads on
line or off, or switching other mains transients equipment,
such as power factor correction equipment. Transients can
also be caused by short circuits, tripping of circuit breakers
in power distribution systems, and inductive coupling
between parallel cables.
EN 61000-4-1 describes the forms of these transients and
how much energy they contain. Their harmful effects can
be limited by various methods. Gas-filled surge arresters
and spark gaps provide first-level protection against high-
energy transients. For second-level protection, most
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