WEG W22 Premium E3 Manual De Instalación, Operación Y Mantenimiento página 69

[IEC 60050 IEV number 426-06-01]
Increased safety "e" (Ex e): type of protection applied to electrical apparatus in which additional measures
are applied so as to give increased security against the possibility of excessive temperatures and of the
occurrence of arcs and sparks in normal service or under specified abnormal conditions.
[IEC 60050 IEV number 426-08-01]
Type of protection "n" (Ex n): type of protection applied to electrical apparatus such that, in normal operation
and in certain specified abnormal conditions, it is not capable of igniting a surrounding explosive gas
atmosphere.
[IEC 60050 IEV number 426-13-01]
Dust ignition protection by enclosure "t" (Ex t): type of protection for explosive dust atmosphere where
electrical equipment is provided with an enclosure providing dust ingress protection and a means to limit
surface temperatures.
[IEC 60079-31 item 3.1]
Gas groups: are subdivided according to the nature of the explosive atmosphere for which they are intended:
Group I: coal mines susceptible to firedamp (methane).
g
Group II: areas not susceptible to firedamp. This group is subdivided into:
g
Group IIA (IEC) / D (NEC): propane, acetone, butane, combustible gas, gasoline, ethyl alcohol, methyl
g
alcohol, benzene, etc.
Group IIB (IEC) / C (NEC): ethylene, cyclopropane, butadiene 1-3, etc.
g
Group IIC (IEC): hydrogen, acetylene, etc.
g
Group B (NEC): hydrogen.
g
Group A (NEC): acetylene.
g
Dust groups: are subdivided into (excepting mines susceptible to firedamp (methane)):
Group IIIA (IEC): combustible fibers / combustible flyings – solid particles, including fibers larger than 500 μm
g
Group IIIB (IEC): electrically nonconductive dusts – solid particles smaller than 500 μm, with electrical
g
resistivity ≤ 10³ Ω.m
Group IIIC (IEC): electrically conductive dusts - solid particles smaller than 500 μm, with electrical resistivity >
g
10³ Ω.m
Group E (NEC): combustible metallic powders, for example: aluminum, magnesium and their commercial
g
alloys.
Group F (NEC): combustible carbonaceous dusts that have more than 8% total entrapped volatiles.
g
Group G (NEC):atmospheres containing dusts not included in Group E and F, including flour, grain wood ,
g
plastic, chemicals, etc.
Flameproof joint: place where the corresponding surfaces of two parts of an enclosure, or the conjunction of
enclosures, come together, and which prevents the transmission of an internal explosion to the explosive gas
atmosphere surrounding the enclosure.
[IEC 60050 IEV number 426-06-02]
Symbol "X": symbol used to denote special conditions for safe use.
[IEC 60050 IEV number 426-04-32]
Equipment Protection Level - EPL: level of protection assigned to equipment based on its likelihood of
becoming a source of ignition and distinguishing the differences between explosive gas atmospheres, explosive
dust atmospheres, and the explosive atmospheres in mines susceptible to firedamp. These EPLs are classified
into:
EPL Ga: equipment for explosive gas atmospheres, having a "very high" level of protection, which is not a
g
source of ignition in normal operation, during expected malfunctions ou during rare malfunctions.
EPL Gb: equipment for explosive gas atmospheres, having a "high" level of protection, which is not a source
g
of ignition in normal operation, during expected malfunctions.
EPL Gc: equipment for explosive gas atmosphere, having a "enhanced" level of protection, which is not a
g
source of ignition in normal operation and which may have some additional protection to ensure that it
remains inactive as an ignition source in case of regular expected occurrences (for example failure of a lamp).
www.weg.net
Manual of Electric Motors 69