The minimum length of motor cables from the power unit to a common point of coupling is
10 m. When a du/dt filter is used, the cables can be less than 10 m long.
Fig. 30: The 12-pulse operation of MR12
A. The MR12 drive
With MR12 you can also use a 12-pulse connection to reduce the harmonics level in the
supply side of the drive. In the 12-pulse connection, the parallel drives are cabled to the
transformer's secondary windings that have a 30-degree phase shift.
5.1.2 CABLE AND FUSE SIZES, IEC
We recommend the fuse type gG/gL (IEC 60269-1) for mains fuses (-F1). Use only fuses that
have a sufficient voltage rating according to the mains voltage. Do not use larger fuses than
what is recommended in Table 8. The fuses are selected for short circuit protection only.
NOTE!
The overcurrent protection of parallel cables must be done with separate fuses.
Make sure that the operation time of the fuse is less than 0.4 seconds. The operation time
agrees with the fuse type and the impedance of the supply circuit.
The table also shows the typical symmetrically shielded copper and aluminum types of the
cables that can be used with the AC drive.
NOTE!
The mains cable and fuse sizes are valid up to a cable length of 100 m, with mains
I
K
= 20 kA.
Fig. 31: The location of the fuses, MR8-MR10
A. The mains fuses B. The cabinet
POWER CABLING VACON · 51
LOCAL CONTACTS: HTTP://DRIVES.DANFOSS.COM/DANFOSS-DRIVES/LOCAL-CONTACTS/
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