Unit 1-10 Part 2 Flashcards
What charges the battery?
Generator or alternator
How much voltage should the alt/gen put out to charge the battery?
If you have a 24 volt battery, what should the output voltage from the alt/gen be?
Should always put out more than the battery can hold to keep the battery charged
28 V system → 24 V battery
What does the system do in the event of a failure of the alternator or any power producing device?
Automatically diverts all power to essential bus and begins to shed loads
List some examples of non-essential loads/buses
Transponders
Communications radios (after telling ATC)
Landing lights
Cabin fans
Non-essential navigation-radios
Interior lights
Why does the inverter output 2 voltages?
Its a lot easier to take items that are cheaper and lighter (coffee pot, lights, tv, tec.) and plug them into the wall instead of purchasing DC powered items, which are a lot heavier
What type of system is DC power distribution?
What makes up this system?
“Split bus” system
Battery bus
2 battery emergency buses
Left main bus
Right main bus
2 sub panel buses
What is an advantage of the split bus system?
One entire bus can fail and all other systems run normally
What is a starter generator?
What type of aircraft use this?
Both a starter motor and a generator
One unit
Direct drive (no disconnect; goes right into the engine)
Saves more weight
Less complex
Turbine powered twins
Turboprop or turbine powered aircraft
What are parallel generators?
What are some advantages?
What is the main disadvantage?
Twin engine = two generators
Generators operated in parallel
May be connected to one bus simultaneously
Both generators “carry the load equally”
Safer
More power
Unable to maintain full output at a low rpm
Describe bus tie breakers and what they look like on a schematic
Same thing as circuit breakers
A half circle that can open or close a connection
What type of battery do piston engines use?
Why?
Lead Acid
They must be checked and replaced more often, usually can be found in small aircraft
What type of battery do turbine engines use?
Why?
Nickel Cadmium (NiCad)
Contains a greater power to weight ratio than lead acid batteries (more power, less weight), normally seen on large aircraft
Describe a split bus system
How would you prevent reverse current flow?
What does this do?
Each alternator has a respective bus
The alternator and busses are “tied together”
Diodes
Keeps a high priority bus from feeding a low priority bus
What is used for “automatic” protection in most aircraft?
How do they provide protection?
Can they be reset?
Fuse (blown fuse)
The filament inside the fuse breaks at a certain current rating
Can’t be reset
Circuit breaker (popped circuit breaker)
The circuit breakers pop open when current is too high
Can be reset (pushed in)
What do ACUs and GCUs do?
If a problem occurs…?
Monitor the bus voltage, amperage, and voltage spikes (interference)
Alt/gen disconnects
