SmartCockpit Dash8 Manual

12.5 (ATA 24) ELECTRICAL POWER
12.5.1 Introduction
The Electrical Power Generation and Distribution System (EPGDS) is used to supply the electri-
cal energy for all onboard electrical equipment. The EPGDS has DC and AC generating sys-
tems. The DC generation system includes a battery system. The EPGDS provides for energy
conversion, distribution, storage, control, protection, monitoring, and indication to the flight crew.
Provision is made for external connection of DC or AC external power while on the ground.
12.5.2 General
The DC generation system is supplied by three NiCad batteries, two engine driven starter/gener-
ators, two Transformer Rectifier Units (TRUs) and an optional Auxiliary Power Unit (APU). The
TRUs supply 28VDC and are powered by two engine driven Alternating Current (AC) generators
that supply 115Volts Alternating Current (VAC).
The power is distributed by an electrical bus system. It re configures for individual power source
and bus failures, by the automatic closing and opening of bus tie contactors.
There are both DC and AC external power receptacles for Ground Power Unit (GPU) connection.
All AC and DC aeroplane services can be operated from the AC generators or the AC external
power alone.
Dash8 - Q400 - Electrical
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