Electrical Flashcards
Max continuous amperage of the engine driven generators
300 amps
The two main aircraft batteries and emergency battery can be charged by..
GPU, APU, and one or both engine driven generators
(PTM pg 2-4)
Each engine has an alternator which provides
AC power to heat the same-side windshield
The voltage readings on the EICAS are taken from (3)
the Left Essential Bus, Right Essential Bus, and Emergency Battery Bus
(E3)
When the main aircraft and emergency batteries are providing power to their respective busses
the EICAS voltages will read approx. 24 volts
(PTM pg 2-12)
When the aircraft generators, APU generator, or a GPU is powering the aircraft
the voltage readings on the EICAS will read approx. 28 volts
During engine start, the amperage readout for the APU or the starter/generator driving the starter will
exceed 300 amps
(AFM pg 1-13)
In the event of a single generator failure, the bus tie should
close after a 5 second ground fault check
(PTM pg 2-34)
Which busses are auto-shed during a single generator failure?
Left and Right Non-Essential Busses
(PTM PG 2-34)
Which busses are auto-shed after a dual generator failure?
Left and Right Main
Left and Right Avionics
Left and Right Non-Essential
(MAN)
(PTM PG 2-36)
During a dual generator failure, the bus tie
remains open
(PTM PG 2-36)
What is auto-shed during a dual generator failure?
Outside (exterior) lights
Wing/Stab Heat
Left and Right Main
Left and Right Avionics
Left and Right Non-Essential
(OH MAN)!
(PTM PG 2-36, 3-12)
In the event of a dual generator failure, a left and right amber NAC on the EICAS will appear because
the NAC SOV’s fail open, but the P2T2 probes are auto-shed
When connecting a GPU, the bus tie should
close
When connecting the APU generator before the left generator comes online, the bus tie should
Close
PTM p2-9
How many times can a circuit breaker be reset, if popped?
One time
Circuit breakers with red rings denote
equipment powered by the Emergency Battery Bus
During engine start, the Left and Right Essential contactors open to prevent
voltage spikes from damaging sensitive avionics components
(PTM pg 2-30)
During engine start, the Left and Right Essential contactors open resulting in the Emergency Battery powering the
Left and Right Essential bus
Left and Right Essential Avionics bus
Emergency Battery bus
(PTM pg 2-30)
The voltage reading on the EICAS should read 24 volts across all busses during engine start showing the voltage output of
Only the Emergency Battery Bus
In the event of a loss of both generators and both main batteries, the first step is to
select each battery “ON,” one at a time
During initial power up, the batteries should be selected on
simultaneously
The GPU is limited to
1500 amps
When the GPU is powering the aircraft, the
Left Generator, Right Generator, and APU Generator cannot come online
When the APU generator is powering the aircraft, the engine driven generators will come on line
automatically once the engines are running
The APU generator will share the amperage load with
the right generator
(PTM pg 2-23)
A GPU or APU should be used for engine start
below 0°C
(PTM pg 2-52)
The APU has been demonstrated to start
at -23°C
The Lear 45 electrical system is a _____-bus system, with the _____ powering the left side of the aircraft, and the _____ powering the right side of the aircraft and the emergency battery bus
Split-bus
Left generator
Right generator
During normal operation with both engines running, the voltage readout on the EICAS for the Left Essential Bus reflects the voltage output of the
Left Generator
During normal operation with both engines running, the voltage readout on the EICAS for the Right Essential Bus reflects the voltage output of the
Right Generator
During normal operation with both engines running, the voltage readout on the EICAS for the Emergency Battery Bus reflects the voltage output of the
Right Generator
A green AVAIL light on the EXT PWR switch indicator, indicates
the GPU is providing good voltage and polarity
The aircraft batteries require ( ) in order for the battery contactors to close on the ground
14 volts minimum
Following a dual generator failure with a subsequent loss of both main aircraft batteries, what radio communications will be available?
All radio communications will be lost
Following a dual generator failure with a subsequent loss of both main aircraft batteries, will an IAP be possible?
No, the aircraft will be unable to fly an instrument approach
How long will the aircraft batteries last after a loss of both generators and completion of the appropriate checklist?
30 min (28 amp hour batteries)
50 min (38 amp hour batteries) - OURS
How long will the emergency battery last after a loss of both generators and completion of the appropriate checklist?
60 minutes
What indications will you have if the emergency battery is discharging?
- Emer battery S/I will say EMER
- White message on CWP (only white one)
Following a single generator failure, can you select the non-essential buses back on?
Yes
Following a dual generator failure, can you select any of the autoshed buses back on?
Yes, you can select the L and R main buses back on, but NOT the non-essential buses.
