12-Pulse Transformer Selection Guidelines; Shielding Against Electrical Noise; External Fan Power Supply - Danfoss VLT AutomationDrive FC 300 Design Manual

Electrical Installation

7.1.4 12-Pulse Transformer Selection Guidelines

Transformers used in conjunction with 12-Pulse frequency converters must conform to the following specifications.
Loading is based on 12-pulse K-4 rated transformer with 0.5% voltage and impedance balance between secondary windings.
Leads from the transformer to the input terminals on the frequency converter are required to be equal length within 10%.
Connection
Phase shift between secondaries
Voltage difference between secondaries
Short-circuit impedance of secondaries
Short-circuit impedance difference between secondaries
Other

7.1.5 Shielding against Electrical Noise

7 7
F-frame Size Units Only
Before mounting the mains power cable, mount the EMC
metal cover to ensure best EMC performance.
NOTICE
The EMC metal cover is only
included in units with an RFI filter.
Illustration 7.33 Mounting of EMC Shield
188
®
VLT AutomationDrive FC 300 Design Guide 90-1200 kW
No grounding of the secondaries allowed. Static screen recommended

7.1.6 External Fan Power Supply

Frame Sizes E and F
In case the frequency converter is supplied by DC or if the
fan must run independently of the mains supply, an
external power supply can be connected via the power
card.
The connector located on the power card provides the
connection of line voltage for the cooling fans. The fans
are connected at the factory to connect to a common AC
line. Use jumpers between terminals 100-102 and 101-103.
If external supply is needed, the jumpers are removed and
the supply is connected to terminals 100 and 101. Use a 5
A fuse for protection. In UL applications, use a LittelFuse
KLK-5 or equivalent.
Terminal no.
100, 101
102, 103
Table 7.26 External Power Supply
MG34S202 - Rev. 2013-08-19
Dy11 d0 or Dyn 11d0
<5% of short-circuit impedance
Function
Auxiliary supply S, T
Internal supply S, T
30°
<0.5%
>5%