Glossary of Terms - M
MagneX®
Interrupter - CPS's primary breaker/switch which takes the
place of a weak link and secondary breaker in a CSP (completely
self-protected) transformer.
Margin or Protection - The difference between
arrester characteristics and equipment withstand level at any
given instant of time. This is a factor of safety when
considering equipment protection. The margin of protection
accounts for various unknowns, such as unusually high magnitudes
of lightning current, separations of transformer and equipment,
and voltage withstand reduction caused by deterioration of old
equipment.
Maximum Continuous Operating Voltage - The
maximum designated root-square (rms) value of power frequency
voltage that may be applied continuously between the terminals of
the arrester.
Maximum Time Current Curve - A curve plotted
on log-log paper that describes the time to complete interruption
at a particular current for a specific device; a complete set of
points (curve) containing the absolute maximum time to circuit
interruption at a specific current for a particular device.
MCM - Thousand circular mils-conductor sizing
above 4/0.
MCOV - Refer to Maximum Continuous Operating
Voltage.
Metal Enclosed - Surrounded by a metal case of
housing, usually grounded.
Metal Oxide Surge Arrester - A surge arrester
utilizing valve elements fabricated from non-linear resistance
metal oxide materials.
Metalclad - Devices in which the conducting
parts are entirely enclosed in a metal casing.
Mini-ELSP - CPS's small amperage rated ELSP
fuses, i.e., 30, 40, 50 A. The term "mini" comes from
the reduction in size compared to the standard ratings.
Minimum Melt Time Current Curve - A curve
plotted on log-log paper that describes the time to complete
melting for a specific interrupter; a complete set of points
(curve) containing the absolute minimum time to melt at a
specific current for a particular device.
MOV - Metal Oxide Varistor arrester
technology/design.
M.O.V.E. - CPS's Metal Oxide Varistor Elbow
(Deadfront) Arrester.
M-Spot - A globule of metal attached to the
main element of a fuse used to lower the melting temperature of
the main element at that point through an amalgamation process
(used in the NX fuse design).
Glossary Index