Electrical and Other Power Systems Practice Flashcards

Vocabulary flashcards covering electrical theory, circuit components, building wiring systems, communication facilities, and mechanical systems like elevators and HVAC, based on the Module 2A lecture notes.

Dynamic Electricity (Electrodynamic)

One of the two general classes of electricity, characterized by the flow of electric charge.

Direct Current (DC)

Electricity that flows in one direction (negative to positive), is uniform in strength, and can be continuous or pulsating.

Alternating Current (AC)

Electricity that reverses its direction of flow at regular intervals, typically with a commercial frequency of $60\text{ Hertz}$ (cycles per second).

Three-Phase Alternating Current

Electricity transmitted as three separate single-phase currents following separate sine curves, with peaks one-third of a cycle apart, requiring at least three conductors.

Electromotive Force (EMF)

The force which causes the movement of electricity in a conductor.

Ampere (Amps)

The unit used to measure the magnitude of an electric current, representing the specific quantity of electrons passing a point in one second.

Ampacity

The current-carrying capacity of a wire or conductor without undergoing undue heating.

Ohm's Law

The relationship between EMF ($V$), Current ($I$), and Resistance ($R$), defined by the formula $V = IR$ or $I = V/R$.

Watt

The unit of power measurement representing the rate of power consumption, calculated as $\text{amperes} \times \text{volts} = \text{watts}$.

Alternator

An electrical generator that produces alternating current ($AC$) by rotating a magnet past stator windings.

Step-up Transformer

A device used to increase electrical power to very high voltages for long-distance transmission.

Service Entrance (SE)

The point where power is supplied to a building, involving wires (the drop) extending from a utility pole or underground source.

Ground-Fault Circuit Interrupter (GFCI)

A device designed to cut off current at an outlet in $1/40\text{ second}$ when a ground fault of $0.0005\text{ amps}$ is reached.

Thhn

Thermoplastic high heat-resistant nylon jacketed wire used in dry and damp locations, primarily in conduit and cable trays.

Mineral Insulated (MI) Cable

A fire-resistant, waterproof cable assembly with an extruded copper sheath, used for emergency generators and fire pumps.

Rigid Metal Conduit (RMC)

The heaviest-weight and thickest-wall steel conduit, which can be used indoors, outdoors, or underground.

Condulet

A type of conduit fitting, such as type LB (location behind), used where a run of conduit must pass through a wall or ceiling.

Private Branch Exchange (PBX)

A private telephone exchange that serves a specific business or office, connecting internal telephones to the public switched telephone network (PSTN).

Coaxial Cable

A transmission line for radio frequency signals where the electromagnetic field exists only between the inner and outer conductors.

Public Address (PA) System

An electronic amplification system comprising a sound source (microphone), an amplifier, and a loudspeaker.

Photoelectric Smoke Detector

A detector that uses an optical beam to search for smoke particles and is most responsive to smoldering fires.

Ionization Chamber Smoke Detector (ICSD)

A detector that uses radioactive material to ionize air and is quicker at sensing flaming fires.

Elevator Governor

A mechanical speed control mechanism used in elevator systems to govern safety.

Escalator

A vertical transport device with an angle of inclination that must not exceed $30^{\text{o}}$ from the horizontal.

Convection

The transfer of heat by the circulation of air around the body.

Variable Air Volume (VAV) System

An HVAC system that keeps air temperature constant while varying the supply air volume to achieve cooling or heating.

Heat Pump

A reversible refrigeration unit that provides both heating and cooling from a central system.

Fusible Link

A component in fire dampers or sprinkler heads that melts when temperatures exceed safe levels, triggering a closure or water flow.