Search results
Results from the WOW.Com Content Network
In Canada and the United States, the Canadian Electrical Code (CEC) and the National Electrical Code (NEC), respectively, use the circular mil to define wire sizes larger than 0000 AWG. In many NEC publications and uses, large wires may be expressed in thousands of circular mils, which is abbreviated in two different ways: kcmil [1] or MCM. [2]
The volt-ampere (SI symbol: VA, [1] sometimes V⋅A or V A) is the unit of measurement for apparent power in an electrical circuit. It is the product of the root mean square voltage (in volts) and the root mean square current (in amperes). [2] Volt-amperes are usually used for analyzing alternating current (AC) circuits.
Electrical code rules will give ratings for wiring where short-term loads are present, for example, in a hoisting motor. For systems such as underground power transmission cables, evaluation of the short-term over-load capacity of the cable system requires a detailed analysis of the cable's thermal environment and an evaluation of the ...
In polyphase electrical systems, generally phase-to-phase, phase-to-ground (earth), and phase-to-neutral faults are examined, as well as a case where all three phases are short-circuited. Because impedances of cables or devices varies between phases, the prospective short-circuit current varies depending on the type of fault.
In the power systems analysis field of electrical engineering, a per-unit system is the expression of system quantities as fractions of a defined base unit quantity. . Calculations are simplified because quantities expressed as per-unit do not change when they are referred from one side of a transformer to t
Calculation of the required breaking capacity involves determining the supply impedance and voltage. Supply impedance is calculated from the impedance of the elements making up the supply system. Customers of an electrical supply utility can request the maximum value of prospective short-circuit current available at their point of supply.
In electrical engineering, the output impedance of an electrical network is the measure of the opposition to current flow (), both static and dynamic (), into the load network being connected that is internal to the electrical source.
In electrical engineering and electronics, a network is a collection of interconnected components. Network analysis is the process of finding the voltages across, and the currents through, all network components. There are many techniques for calculating these values; however, for the most part, the techniques assume linear components.