17
SAFIR 5L
OPERATION AND ATTENDANCE MANUAL
PG 01-31
Fig. 5. APU Function Flow Chart
APU
- Auxiliary Power Unit SAFIR 5L
FP
- Fuel Pump
EV1
- Electromagnetic Fuel Valve of Filter and Servo Block
EV2
- Electromagnetic Valve of Oil Filter
EV3
- Electromagnetic Valve of Oil Tank - air vent.
EV4
- Electromagnetic Valve of Oil Drain
ES
- Electric Starter
EU
- Ignition Exciter
ATS
- Pneumatic Starter
TP
- Speed Transmitter
EC -Control
Box
EV1, EV2, EV3, EV4
-
open
FP, ES, EU
-
when nergized
Timing circuit
2 – 10 – 13 – 35 s
-
actuated
APU Start up
After 2s Control Systém
does not have adequate
signal from TP
Sub-speed reached in 35s ES, EU
disconected from the
power supply
Timing 13 s
reached at the exhaust
gases
temperature
˂
150°C
(302°F)
Timing 35
s finished before
reaching
sub-speed
The APU speed reached
idling
APU CUT – OFF
by pilot
Inadequate oil pressure
after 30s
of APU operation
By switching
off the svitch
„DELAY
STOP“
Decrease the rotational
speed at idle and two
minutes waiting at idle
in order to cool the
turbine.
EV1, EV2, FP
- disconnected from power supply
Timing 180s
- actuated
After 180s EV3, EV4 switched off
from the power supply
By switching off the svitch
„EMERGENCI STOP“
The APU reached
The operating speed
APU CUT – OFF
by automatic protection system
Two brakers and
switch switched
RUN
Push the
START BUTON
