Electrics 3 - battery / switches / generator Flashcards
Aircraft batteries are made of (3)
Lead-acid
nickel cadmium (NiCd)
Lithium (LiB)
Which types of battery are prone to thermal runaway?
nickel cadmium (NiCd)
Lithium (LiB)
Because they have a negative temperature coefficient of resistance
Batteries are comprised of cells. How are they wired, and why?
series, to reach the desired output voltage
A battery system will either be 12 or 24 vault. What will a battery read when being discharged?
What will the battery read when being charged?
Voltage will drop slightly when under load.
Will require 14v (ish) to charge
Battery capacity is measured in what unit?
What can reduce it?
Ampere hours
the cold. (also reduced the rate of discharge
Thermal runaway can be caused by (3)
excessive heat (internal or external)
damage / mechanical damage
Excessive battery charge
Lithium batteries are not just there to power the aircraft. Where else can they be found?
Passenger devices
The only way to extinguish a lithium battery fire is to…
cool it with water or non-flammable liquid
What is a bussbar
substantial connector, powered by an electrical source which has attachment points to allow connection of multiple loads.
What is nominal voltage, how does changing deviate from this?
Standard voltage, 12v or 24v but there is an operating range around this.
20% more for charging.
In a NiCad battery, what electrolyte is used?
The plates are made of Nickel Oxide and Cadmium which are both suspended in a electrolyte solution of potassium hydroxide.
Thermal runaway is?
Uncontrolled increase in temperature due to an uncontrolled increase in current.
The battery does not need to be damaged.
Thermal runaway can be seen as a cycle of what three things?
Current and temperature rise
resistance drops
Material Temperature Characteristics
…..
…..
As a rule.
Connecting batteries in series will increase _________
whereas connecting batteries in parallel will increase _________
Series - Increase voltage
Parallel - increase current
