2 Engineering
2.2 Electrical power network
DC1 variable frequency drive 12/13 MN04020003Z-EN www.eaton.com 31
2.2.6 Mains chokes
Main chokes (also known as commutating chokes) increase the inductance
of the mains supply cable. This extends the current flow period and dampens
mains voltage drops.
Towards the variable frequency drive, the main chokes dampen the interfer-
ence from the supply network. This increases the electric strength of the
variable frequency drive and lengthens the lifespan (diodes of the mains
power rectifier, internal DC link capacitors).
￫
For the operation of the DC1 variable frequency drive, the
application of main chokes is not necessary. We do recommend
however that an upstream mains choke is used since the
network quality is not known in most cases.
While planning the project, consider
that a main choke is only
assigned to a single variable frequency drive for decoupling.
When using an adapting transformer (assigned to a single vari-
able frequency drive), a main choke is not necessary.
Main chokes are designed based on the mains-side input
current
(I
LN
) of the variable frequency drive.
The mains chokes recommended for DC1 variable frequency
drives are listed in the annex ( Table 32 and Table 33)
( Section 11.16, „Mains chokes“, page 215).
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