2 Flashcards
Contactors
A kind of Power Relay wherein it operates for as long as the current flows
If current flows, contactors are closed but when power is cutoff, it is opened disconnecting from the circuit.
The electromagnetic operating device of a contactor consist of a coil and the iron armature. When a current is switched on for the coil, a magnetic field is generated which moves the armature and the contacts. The contacts are operated for as long as the current flows.
Breaker
Needs a short pulse to close and another pulse to open the circuit.
The electromagnetic operating device of the breaker type power relay works in a different way. It needs only a short current pulse to close the contacts and a second pulse to open or trip the contacts again.
Fuse and Circuit breaker
Both are used as protective devices. Fuses are less accessible because you need a replacement for each busted fuse and it is time consuming in changing them. Circuit breakers can be reset multiple times and can be used as a switch making it more efficient than the fuse.
TRU (Transformer Rectifier Unit) and Static Inverter
TRU convert AC to DC to provide 28V DC power for the DC consumers during flight while the Static inverter converts DC to AC to provide 115V / 400Hz AC power for some AC consumers duting flight.
Two types of continuos loops
Pnuematic pressure loop and Semiconductor Loop
Pnuematic pressure loop operates when the temperature is high, the pressure of gas in sealed tube will closed the pressure switch to trigger the alarm via the control unit. While Semiconductor loop have a material that decreases its electrical resistance with increasing temperature. The trigger will alarm when the resistance is decreases below the threshold
Two types of smoke detectors
Smoke detectors are usually use in cargo compartment, toilet, and avionic compartment. One type of smoke detector is optical system, it uses infarared lazer. If the laser is blocked it will sense and trigger an alarm. While Ionization uses radioactive source to detect smoke and it is rarely used
Differentiate lighting technologies available
Types of light sources:
Incandescent Light - light is produced by temperature radiation, it uses tungsten filament, it is encased in a gas filled bulb.
Halogen Incandescent lamps - it is the improve incandescent lamp. It has 50% more effectiveness and it has longer lifetime because it is filled with halogen gas.
Gas discharge lamp - gas atoms generate light when ionized by an electric current
High intensity discharge lamp - it is a gas discharge lamp type. It produces light when gas is heated.
Light Emitting Diode - it is a special type of semiconductor diode. It releases energy in the form of photons.
External Lighting
Navigation lights- is to mark aircraft position and give an indication of its orientation. Red for left side, Green for right side, and white rear side of the aircraft.
Anti Collision Light- has three white flashing strobe light. It helps to mark the aircraft position.
Landing light - to provide sufficient illumination to flight crew during landing
Runway turnoff and taxi lights- used to ensure sufficient illumination of all taxiways during taxiing operations on ground.
Ice inspection lights - used to provide sufficient illumination for the crew to examine the area for ice formation
Logo lights- it is installed on trimmable horizontal stabiliazer to light the airline logo.
Internal light
Enable the flight crew to operate the aircraft safely, the cabin crew to carry out their duties effectively, and the passenger to feel comfortable.
Instrument light
To ensure that the cockpit instruments are readable during all ambient lighting conditions.
Storm lighting
Provides maximum lighting in the cockpit to ensure main instrument panel lights and ambient lights are at their maximum brightness
Type of ice
Clear Ice or Glaze - If the temperature of the droplets is between zero and minus 10 degrees celcius.
Rime Ice - if the temperature of the droplets is below minus 10 degrees celcius.
Frost- builds on the surface of aircraft that are parked outside in cold nights.
Cons.- increase in drag, weight, and decreased lift
