User's Manual

SYSTEM DESCRIPTION, INSTALLATION, AND MAINTENANCE MANUAL
eNfusion® HSD-440 Mark 2 Terminal
23-15-30 3-4
3 JUN 10
C. Chassis Grounding
The HSD-440 Mark 2 Terminal tray-mounted assemblies must be electrically bonded to
the airframe. Make sure that the mating surfaces are free from contaminants such as
paints or other non-conductive elements. Where surface preparations are insufficient to
ensure a proper bond, EMS Aviation recommends using a short, tin-coated, copper
bonding strap of at least 6.35 mm (0.25 in.) in width. The LRU and tray assemblies should
provide a low impedance path of <0.2 ohms.
4. Electrical Installation
This section provides electrical installation details for HSD-440 Mark 2 Terminals.
A. Cabling and Connector Requirements
This section provides general electrical installation information on power, ground,
shielding requirements, and cabling.
(1) Power Requirements
The HSD-440 Mark 2 Terminal can operate from the aircraft’s +28 V dc or 115 V ac,
400
Hz (nominal) power supply. If both power sources are connected, the terminal
will use the 115
V ac supply.
(2) Ground Requirements
Improper grounding can lead to ground loops and induced Electromagnetic
Interference (EMI) or Radio Frequency Interference (RFI). When installing an
HSD-440 Mark 2 Terminal, follow standard grounding practices for both chassis and
cabling shields. Refer to
"Chassis Grounding" on page 3-4 for chassis and tray
grounding instructions.
(3) Cable Shielding and Termination
The preferred method of cable shield termination is in accordance with NEMA WC
27500:2000 and ARINC 741. ARINC Report 413A—Guidance for Aircraft Electrical
Power Utilization and Transient Protection provides more detailed information in
Attachment 3-2, Wire Shielding and Grounding Requirements and in Appendix 7.
Unless otherwise stated, all cable shields must be connected to the closest aircraft
ground at both ends of the cable and on both sides of any production break in the
cable. Where applicable, terminate shields with connectors via the backshell or via
a pigtail with a suitable termination to the closest aircraft ground.
General aviation cable-routing guidelines apply. See Table 3-1 for detailed
information.
NOTE: Typically, Ethernet and ISDN cables have multiple shields; terminate each
shield separately.