Mains Chokes - Eaton PowerXL DB1 Installation Manual

2 Engineering

2.5 Mains chokes

2.5 Mains chokes
32
Mains chokes reduce the Total Harmonic Distribution (THD) and mains feed-
back. The apparent current on the mains side is then reduced by around
30 %.
The mains chokes dampen the interference from the supply network toward
the variable frequency drive. This increases the electric strength of the vari-
able frequency drive and lengthens the lifespan (diodes of the mains power
rectifier, internal DC link capacitors).
￫
It is not necessary to use mains chokes in order to run the DB1
variable frequency drive.
However, we recommend using a mains choke if the electrical
supply system's quality is not known:
• Large voltage peaks (e.g., when switching large loads
directly)
• Correction systems (without series inductors)
• Power supplied via conductor rail or slip ring systems
(e.g., traveling cranes)
While planning the project, consider that a mains choke is only
assigned to a single variable frequency drive for decoupling.
When using an adapting transformer (assigned to a single variable
frequency drive), a main choke is not necessary.
Mains chokes are designed based on the mains-side input current
(I ) of the variable frequency drive.
LN
￫
When the variable frequency drive is operating at its rated cur-
rent limit, where the u
choke causes a reduction of the frequency inverter's greatest
possible output voltage (U
voltage U
T
￫
For the rated mains contactors for DB1 variable frequency
drives, please refer to ￫ section 5.7, "Mains chokes",
page 86.
DB1 Variable Frequency Drives 09/17 MN040031EN www.eaton.com
-value is approximately 4 %, the mains
K
) to approximately 96 % of the mains
2
.
LN