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1: Electrical Terms and Definitions

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    18013

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    • 1.1: Ohm’s Law and Watt’s Law
      This page explains Ohm's Law, which connects voltage, current, and resistance, using a water tank analogy to illustrate how resistance impacts current flow. It also discusses Watt's Law, which defines electrical power as the rate of energy transfer, calculated as the product of voltage and current. An example shows that a 10-volt source with 10 amps results in 100 watts of power.
    • 1.2: Overload and Overcurrent Terms
      This page discusses electrical overload and overcurrent, defining inrush current as a high initial draw from motors that can cause disturbances if protective devices are not adequately sized. Overload is characterized by a gradual current rise from excessive load, while overcurrent involves rapid spikes often due to faults. Both situations can inflict damage on equipment through thermal and mechanical stress, highlighting the necessity of protective devices like fuses and circuit breakers.
    • 1.3: Overload and Overcurrent Protection Devices
      This page covers overload and overcurrent protection devices, highlighting fuses and circuit breakers. Circuit breakers automatically open circuits to prevent faults and can be reset, while fuses melt under fault conditions and come in fast-acting and time-delay varieties. Key ratings for these devices include voltage rating, continuous-duty rating, and interrupting capacity, which determines the maximum fault current they can safely handle.
    • 1.4: Single-Phase Systems vs. Three-Phase Systems
      This page compares single-phase and three-phase electrical systems. Single-phase systems use two wires and are suitable for control circuits, while three-phase systems, with three conductors and a 120° phase shift, are designed for complex loads like motors. Balanced loads in three-phase systems cancel out currents, negating the return conductor's necessity, while unbalanced loads may require a neutral.
    • 1.5: Low-Voltage Release vs. Low-Voltage Protection
      This page explains the concepts of low-voltage release (LVR) and low-voltage protection (LVP) in circuit design related to power restoration. LVR enables automatic restarting of loads when voltage returns, enhancing safety, while LVP necessitates manual intervention to avoid risks. Magnetic contactor designs support LVP, whereas maintained contact designs usually provide LVR.
    • 1.6: Self Test 1
      This page outlines an interactive practice quiz that allows for multiple attempts. It provides a link for online access, and notes that quiz questions are also available in the accompanying book for offline use.

    Thumbnail: Circuit Breakers (Unsplash License; Markus Spiske via Unsplash)

    This page titled 1: Electrical Terms and Definitions is shared under a CC BY 4.0 license and was authored, remixed, and/or curated by Aaron Lee (BCcampus) via source content that was edited to the style and standards of the LibreTexts platform.