|
曝光台 注意防骗 网曝天猫店富美金盛家居专营店坑蒙拐骗欺诈消费者
Electronic Control Unit
The electronic control unit (ECU) is powered from two 28V inputs: primary, via the battery bus, and secondary, via the main battery direct bus. The PWR FUEL switch/light controls the primary power, and secondary power is directly connected via circuit breaker. Secondary power is used by the ECU as a backup when the ECU’s primary voltage drops below 22V. The ECU’s internal logic disconnects the secondary 28V input (removing power from the ECU) after shutdown, and when all ECU shutdown tasks are completed.
The ECU monitors APU sensors and switches, and sets the appropriate fuel and temperature schedules. The ECU senses changes in shaft or bleed load, and adjusts the fuel supply to maintain a constant RPM at 100%. In addition, the ECU sends APU operating data to the data concentrator units for EGT and RPM display on the EICAS page. The ECU also provides operating data for fault identification on the APU FAULT panel, located on the left aft fuselage (next to the ground air adapter).
APU Starter
The APU starter motor is DC-powered by the APU battery direct bus, and transfers cranking power to the APU drive shaft through the accessory gearbox. The white START legend in the upper half of the START/STOP switch/light illuminates whenever the starter motor is engaged.
Ignition System
The ignition system ignites the fuel/air mixture during start. The system is energized after the START/STOP switch/light is pressed in and APU rpm reaches 5%. Ignition is de-energized when the rpm reaches 99%.
AUXILIARY POWER UNIT Description Vol. 2 05.10.13
Oct 05/06
APU Start and Ignition
Figure 05.10.7
AUXILIARY POWER UNIT Description Vol. 2 05.10.14
Oct 05/06
APU Start
With the battery master switch ON, pressing the PWR FUEL switch/light results in the following:
.
APU ECU is powered, and after a 3-second BITE test, the APU EGT indication shows actual EGT (ambient temperature), and the rpm shows actual percentage;
.
APU fuel shutoff and negative-G shutoff valves open; and
.
APU fuel pump energizes.
Pressing the START/STOP switch/light signals the ECU to initiate the start sequence. The starter engages, the start legend is illuminated on the APU panel, and the following events occur:
.
5% rpm – Fuel and ignition energized (a rapid increase in temperature, as shown on the EGT gauge, indicates light-off);
.
35.45% rpm – Starter cutout – START (white legend) out;
.
95% rpm + 4 seconds (approx) – APU AVAIL (green legend) on;
.
99% rpm – Ignition deactivated; and
.
100% rpm + 15 seconds (approx) – APU GEN OFF caution message on EICAS (indicating that the APU generator has not been selected on).
中国公务机网 www.gongwuji.com
公务机翻译 www.aviation.cn
本文链接地址：庞巴迪挑战者605公务机机组操作手册 CL605-辅助动力装置 AUXILIARY_POWER_UNIT(6)
| 
