Introduction to Three-Phase Power and Controls

Vocabulary flashcards covering key definitions and concepts related to three-phase electrical systems, line-to-line/line-to-neutral voltages, wiring configurations, and lab equipment from the lecture.

Three-Phase Power

An electrical power system delivering three discrete sinusoidal waveforms separated in phase, providing smoother torque and three power kicks per cycle to operate heavy motors.

Line-to-Line Voltage

The voltage potential difference measured between any two phase lines ($L1$, $L2$, or $L3$) in a three-phase system, equal to $208\,\text{V}$ in the lecture example.

Line-to-Neutral Voltage

The voltage potential difference measured between any single phase line ($L1$, $L2$, or $L3$) and the neutral conductor ($N$), equal to $120\,\text{V}$ in the lecture example.

Four-Wire System

A three-phase wiring configuration consisting of three line conductors ($L1$, $L2$, $L3$) plus a neutral line, allowing both $208\,\text{V}$ phase-to-phase and $120\,\text{V}$ phase-to-neutral power delivery.

Three-Wire System

A three-phase wiring configuration consisting only of three line conductors ($L1$, $L2$, $L3$) without a neutral line, utilized where line-to-neutral voltage is unnecessary.

Neutral Conductor

The return line in an electrical circuit through which current exits back from a hotline after performing work.

Y-Configuration (Wye)

A circuit arrangement inside a transformer box or fuse box where three independent phase wires connect to form line-to-line and line-to-neutral power outputs.

85MT5

A modular electrical motor control training station manufactured by Ametrol featuring removable panels, indicator lamps, switches, and control transformers.

Overload Relay

A protective device that measures electrical current flow and trips the circuit to shut down a motor if excessive current is detected over a sustained period.

Phase Shift

The angular separation between waveforms in a multi-phase system, calculated as $360^\text{o} / 3 = 120^\text{o}$ between adjacent phases in three-phase power.