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Inrush current. Inrush current, input surge current, or switch-on surge is the maximal instantaneous input current drawn by an electrical device when first turned on. Alternating-current electric motors and transformers may draw several times their normal full-load current when first energized, for a few cycles of the input waveform.
Ampacity rating is normally for continuous current, and short periods of overcurrent occur without harm in most cabling systems. Electrical code rules will give ratings for wiring where short-term loads are present, for example, in a hoisting motor.
Electromagnetism. In electromagnetism, current density is the amount of charge per unit time that flows through a unit area of a chosen cross section. [1] The current density vector is defined as a vector whose magnitude is the electric current per cross-sectional area at a given point in space, its direction being that of the motion of the ...
The prospective short-circuit current (PSCC), available fault current, or short-circuit making current is the highest electric current which can exist in a particular electrical system under short-circuit conditions. It is determined by the voltage and impedance of the supply system. It is of the order of a few thousand amperes for a standard domestic mains electrical installation, but may be ...
Current limiting is the practice of imposing a limit on the current that may be delivered to a load to protect the circuit generating or transmitting the current from harmful effects due to a short-circuit or overload.
Three-phase electric power (abbreviated 3ϕ[1]) is a common type of alternating current (AC) used in electricity generation, transmission, and distribution. [2] It is a type of polyphase system employing three wires (or four including an optional neutral return wire) and is the most common method used by electrical grids worldwide to transfer power. Three-phase electrical power was developed ...
Maximum power transfer theorem. In electrical engineering, the maximum power transfer theorem states that, to obtain maximum external power from a power source with internal resistance, the resistance of the load must equal the resistance of the source as viewed from its output terminals. Moritz von Jacobi published the maximum power (transfer ...
The graph opposite shows that there is a minimum in the frequency response of the current at the resonance frequency when the circuit is driven by a constant voltage. On the other hand, if driven by a constant current, there would be a maximum in the voltage which would follow the same curve as the current in the series circuit.