Block III (2b Electrical System)

What is the negatively charged part of an atom?

Electron

What is the flow of electrons through a conductor?

Current

What unit is current measured in?

Amperes (AMPS)

What are the two types of current?

Direct Current (DC) and Alternating Current (AC)

Which type of current is a continuous flow of electrons in one direction through a circuit?

Direct Current (DC)

What type of current reverses direction in a circuit at regular intervals (back and forth)?

Alternating Current (AC)

What is the electromotive force that pushes current through a conductor?

Voltage

What is the opposition of current flow called?

Resistance

What unit is resistance measure in?

Ohms (Ω)

What is the number of complete cycles AC makes per second called?

Frequency

What unit is frequency measured in?

Hertz (Hz)

What is a material that permits the flow of electrical current called?

Conductor

What is a material that prevents or isolates the flow of electrical current called (Typically found around a conductor to contain electrical current)?

Insulator

What protective device has a metal strip that melts when enough heat is generated by excess current?

Fuse

What protective device trips and opens the circuit when there is excess current flow (can be reset after cool-down period)?

Circuit Breaker

What component can stop, start, vary, or change the direction of current flow?

Control Device

What type of control device operates by moving a toggle (lever) to open or close a circuit?

Toggle Switch

What type of control device is a micro switch: requires a small movement to contact linkage to a moving surface which opens or closes a circuit (refrigerator)?

Limit Switch

What is installed to protect toggle switches from accidentally being activated/ deactivated (e.g. flight controls, landing gear, high voltage electrical currents)?

Guard Switches

What color is the guard switch that closes over a toggle switch without affecting the position (on/ off)?

Black

What color is the guard switch that closes over a switch and forces a specific (defaulted) position?

Red

What kind of guard switch uses cover guards with a hole for finger access or will hinge to the side for access?

Push-Button Switch

What component of an AC system contains controls and indicators necessary to operate and monitor the electrical system?

Electrical Control Panel

What component of an AC system is the power distribution point for all AC circuits?

AC Bus Bar

What component mechanically generates AC electrical power to operate aircraft systems?

AC Generator/ Alternator Drive Units

What component is engine driven and uses oil pressure to rotate the AC generator at a constant speed maintaining frequency (Hz)?

Constant Speed Drive (CSD)

What is the combination of a CSD and AC Generator called?

Integrated Drive Generator (IDG)

What component regulates generator output to protect the electrical system?

Generator Control Unit (GCU)

What component steps down voltage and converts AC to DC power?

Transformer Rectifier (TR)

What component is the connection point for an external electrical cord?

External Electrical Power Receptacle

What system provides electrical power in emergencies and contains an emergency generator and emergency generator control unit?

Emergency Power System

What electrical system uses a battery to provide initial, emergency, or auxiliary power?

Direct Current (DC)

How many volts is an aircraft battery normally rated at?

28 Volts

What is the power distribution point for DC Systems?

DC Bus Bar

What uses graphic/ electronic symbols to trace circuits and learn the overall system operation (is a simple version)

Electrical Schematic

What uses graphic/ electronic symbols to trace circuits, identify types and sizes of wires, and is used to troubleshoot and repair systems (more detailed)?

Wiring Diagram

True or False:

Schematics and Wiring Diagrams are often used in conjunction to troubleshoot and repair an electrical system

True