Electric Utility Glossary - Section M
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Mandrel – A cylindrical or cone-shaped device that is pulled through conduit (pipe) to remove debris.
Maxwell’s Equations – Maxwell’s Equations were created by James Maxwell and they include four concise ways to explain the fundamentals of electricity and magnetism in a mathematical form. Maxwell’s Equations include:
Gauss’ Law of Electricity
Gauss’ Law of Magnetism
Faraday’s Law of Induction
Ampere’s Law
Maxwell, James (1831-1879) – James Maxwell was a research scientist, physicist and mathematician. Maxwell is considered a pioneer in the world of electricity because he was able to apply a concise combination of mathematical equations that are considered the fundamentals of electricity and magnetism, known as Maxwell’s Equations. These equations influenced other pioneers in the field of electricity and theoretical physics.
MCM – An obsolete method of measuring conductor size that stands for thousand circular mils. M represents 1,000 (in roman numerals). C represents circular, and mil, M, is 1/1000 of an inch. A wire that is one mil in diameter has an area of one circular mil or 1 MCM. KCMil (see above) has replaced MCM for sizing conductors.
Microturbine – A tiny jet engine that uses the hot exhaust gas to spin an electric generator.
Mid-Span Tap - A connection from a secondary distribution line to customers that is made in between the poles. The connection in the middle of the span.
Midwest Reliability Organization (MRO) - See NERC.
MOAB – An acronym for a Motor-Operated Air-Break switch. The “Motor” is an electric motor that allows the switch to be remotely controlled by a system control center. The “Air Break” refers to a visible break in the air that allows crews to see that the switch is truly open.
MRO – Midwest Reliability Organization - See NERC.
MVAR – A unit of measure for reactive power representing megavolt amperes reactive. It is pronounced “mega-var.” (See reactive power)
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