310102jA Fundamentals of Alternating Current Part A 2015 (TF)

Alternating Current (ac)

A type of electrical current that reverses direction periodically.

Electromotive Force (emf)

The voltage generated by a battery or by the magnetic force according to Faraday's Law.

Frequency (f)

The number of cycles per second, measured in hertz (Hz).

Sine Wave

A mathematical curve that describes a smooth periodic oscillation.

Peak Voltage (Emax)

The maximum voltage in a waveform.

Instantaneous Voltage (e)

The voltage at a specific instance of time in the cycle.

Root Mean Square Voltage (Vrms)

The effective value of an ac voltage.

Phase Angle

The fraction of a cycle represented by the angle at any point in time.

Magnetic Flux Density (β)

The measure of the magnetic field strength, typically expressed in teslas (T).

Mechanical Degrees vs Electrical Degrees

Mechanical degrees refer to rotation in degrees, while electrical degrees refer to the equivalent cycles in electrical circuits.

Conductor

A material that permits the flow of electric current.

Ohm's Law

A basic principle stating that current is proportional to voltage in a resistive circuit.

Calculation of Frequency

Determining frequency by dividing the number of cycles by the time period.

One Cycle

Occurs when a periodic wave returns to its initial starting point.

Phasor Diagram

A graphical representation of the magnitude and phase of a sinusoidal function.

Voltage Peak (Vpeak)

The maximum instantaneous value of voltage in an ac wave.

Voltage Alternation

Refers to the sections of the sine wave representing positive and negative cycles.

Oscillation

A repetitive variation in a system about its equilibrium position, in this context refers to the cycles of ac.

Cutting Lines of Flux

The process where a conductor moves through a magnetic field, inducing voltage.

Voltage at Various Angles

Calculating instantaneous voltage using the maximum voltage and the sine of the angle.

Electrical Cycle

A complete sequence of an alternating current from positive to negative and back again.