Aircraft Electrical Systems Flashcards
What is battery capacity measured in?
It is measured in amp-hours
What is the purpose of a circuit breaker?
To protect the circuits and wires from fire. The circuit breaker opens the circuit when an overload exists.
What are the two principles on which circuit breakers operate?
Thermal and magnetic.
What tool is used to measure the size of unmarked electrical wire?
A wire gauge
What are the colors of aircraft position lights and where are they mounted?
A green light is mounted on the right wingtip, a red light on the left wingtip, and a white light mounted in a position where it is visible from the rear of the aircraft.
What are the factors to be considered when selecting wire size for electrical power?
allowable power loss,permissible voltage drop, current-carrying ability of the conductor.
When is a circuit breaker or fuse designed to open the circuit?
When an overload or circuit fault exists
What type of breakers are not acceptable for use in aircraft?
Auto-reset type breakers.
What is a slow-blow fuse?
A fuse that compensates for surges and high inrush current by not blowing for several milliseconds.
What are the three most common faults that occur in an electrical circuit?
They are open circuits,shorted circuits,and low power in circuits.
What size electrical conduit should be used for a specific cable bundle?
25% larger than the maximum diameter of the wire bundle.
What color insulator on a solderless connector is proper for a 10-gauge wire?
Yellow.
How should electrical switches typically be oriented in the on position?
Up or forward.
When should electrical switches be de-rated from their normal current rating?
When using high rush-in circuits,inductive circuits,and for DC motor circuits.
When do DC electric motors draw several times their rated current?
During Starting
What would cause an AC electrical motor to run too fast?
An excessive supply of voltage, or the motor field windings shorted.
What would cause an AC electrical motor to run too slow?
Low applied voltage, defective wiring, or no lubrication.
How is the output voltage of an alternator controlled?
By using a voltage regulator to control the exciter field current and thus regulate the exciter output voltage applied to the alternator field.
What should be checked before any aircraft electrical load is increased?
The associated wires, conductors, and circuit protection devices should be checked to determine that the new load will not exceed the rated limits of these units.
What is the main advantage of using AC for aircraft electrical power systems?
The principal advantage is that the voltage of AC power systems is easily changed using transformers.
Therefore, you can transmit power at high voltage and low current, thus reducing the size and weight of the wiring in the circuit.
In AC power systems, how is DC obtained for battery charging?
By using rectifiers.
What warns pilots of overheating batteries?
A thermal sensor in the battery and a light in the cockpit.
How long should bonding jumper wires be made?
as short as possible to prevent an increase in resistance.
What are the two items that wear on a starter generator?
Commutator and the brushes.
What powers the ELT?
The ELT battery.
What is the purpose of a static wick?
It dissipates static energy from the aircraft to avoid damaging electrical components.
What are two types of AC generators?
Single phase and three phase
When repairing aircraft electrical components what reference do you use?
The manufacturers maintenance manual.
What is the preferred method of charging NICAD batteries?
Constant current charger.
What is the Max allowable voltage drop from a generator to a bus bar?
2%
What system components can be used for troubleshooting an aircraft electrical system?
Voltmeter and ammeter.
