15.20 Flashcards
Engine fire or overheat detection sensors are always what type?
Continuous loop
Two different types of continuous loop systems?
Semiconductor loop
Pneumatic pressure loop
Pneumatic pressure loop called a what loop?
Systron and donner
The semiconductor loop is named what after manufacturers?
Kidde
Graviner
Edison
Fenwal
The switch located in the thicker end of the loop is called what?
The responder
High resistance is what type of condition
Normal
Low resistance condition is what?
Alarm condition
What type of system areall essential fire warning systems?
Dual loop system
How does dual loop system work?
Two sensors
Fire warning only triggered if both sensors are triggered
The ceramic material functions like a what?
An endless number of resistors
Ceramic materials have what type of coefficient?
Negative temperature coefficient characteristics
To prevent the situation of a fire which cannot be detected due to an open loop what is done?
The end of loop is connected to beginning and closed loop is formed
A short circuit would trigger a fire warning in a simple system like the wheel well system because resistance decreases below what?
Alarm threshold of 500 ohms
If only one loop reports an alarm for a longer time than 15 seconds the pilot gets what message?
Loop fault message
What does the two switches do in a gas pressure loop?
First one is the monitor and integrity switch
Second one is an alarm switch and closes at a higher gas pressure
