Phase III Block IV - Electrical Systems Flashcards
What are some hazards when dealing with electrical system?
- Avoid Contact with energized electrical circuits 2. Pull and Tag-out circuit breakers on equipment being repaired.
- If it is not unsafe to do so, work only with one hand, keeping the other hand at your side, away from conductive materials.
- If an individual comes in contact with a live electrical conductor, do not touch the equipment, cord or person. Disconnect the power source from the circuit breaker or pull out the plug using a belt.
What is voltage?
Voltage is the electrical force which causes current to flow in a circuit. Voltage is measured in volts (v)
Explain electrical current?
Current is the movement of electrical charge through the electronic circuit. Current is measured in amperes (AMPS A).
What is resistance?
Resistance causes an opposition to the clow of electricity in a circuit. Resistance controls the amount of voltage and/or amperage in a circuit. Resistance is measured in ohms (X).
What is the definition of Hertz?
Hertz is an electrical unit of frequency equal to one cycle per second. Cycles per second are measured in hertz (Hz).
What is an electrical bus?
An electrical bus is a distribution point in an aircraft electrical system to which the battery and the generator(s) are connected. Components derive their power from a Bus.
Explain the Generators?
An air-cooled, engine driven AC generator, rated 40 KVA at 200/115 volts, is mounted on the engine accessory drive pad of each engine.
Explain the aircraft battery system?
The battery system provides a means of operating certain essential DC equipment when external power from the transformer-rectifier system is not available. A 24 volt battery is installed in a recessed compartment on the lower left side of the nose section.
What are the four main distribution buses?
Essential, main, left hand and right hand AC buses. On aircraft 165313 and up there are also essential and main avionics bus.
What is AC power distribution controlled by?
It is controlled by contactor relays so that essential aircraft systems are powered at all times. With one engine driven generator the essential and main AC buses will be powered. With two generators all AC buses will be powered.
How is circuit protection provided?
It is provided by circuit breakers, fuses and current limiters. The main location is in the flight station on the pilots and co-pilots circuit breaker panels. There is also circuit protection on the upper main distribution panel, located on the forward side of the 245, and the aft junction box located in the cargo compartment.
How is AC power regulated?
It is regulated through the use of five voltage regulators. One for each AC generator provides automatic regulation of generator output voltage. On aircraft 165313 and up power is regulated through generator control units. The units are mounted on the electrical control and supply rack.
