Electrical installation and wiring
4-8 Chapter 4: Installation 98-145168-A
4.3.3 To wire the CSDU with AC input
ARINC-781 compliant.
The aircraft power bus provides the electric power required to operate the CSDU, and a
chassis connection to the aircraft chassis and the installation tray. The +115 VAC power
wire must include a circuit breaker capable of carrying the required current continuously
under the required environmental conditions.
The following drawing shows the wiring of the CSDU AC power supply. Requirements to the
wiring are stated in the notes on the drawing and in the section To wire the SCM on page 4-
10.
The COLD does not need to go through a break.
The COLD must not be connected to chassis ground. Connect the COLD to the aircraft
power bus as stated in the following table.
Pins for AC power
The following list shows the pins used for the AC power supply.
Figure 4-3: Wiring AC power
CSDU
BP1 +115 VAC Neutral (Cold)
Aircraft power Bus
115 VAC
(360 Hz to 800 Hz)
[1] + [2] Total resistance (Hot and cold) max. 1 Ohm incl. circuit breaker.
[3] Directly to installation tray and aircraft chassis, max. 25 mOhm resistance.
[4] Compatible with an aircraft circuit breaker of the following characteristics: 115VAC /
5A Solid state power controllers (SSPC)
BP3
BP5 +115 VAC Line (Hot)
Chassis
[4]
5 A
[1]
[3]
[2]
CSDU pin Name Description
BP1 +115 VAC Line (Hot) +115 VAC Line (Hot) power input from aircraft
power bus.
BP5 +115 VAC Neutral (Cold) +115 VAC Neutral (Cold) return from aircraft
power bus.
BP3 Chassis Ground Chassis connection, connect to the installation
tray and Aircraft chassis.
Table 4-2: CSDU pins (AC input)
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