NORD Drivesystems B1000 - Manual (Page 36)

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INTRODUCTION
G1000 – Subject to Change Without Notice
Production Type
Following the equipment category in the explosion
protection declaration is the lower case letters that
indicate the exact protection type of the equipment.
Depending on the zone and equipment category
different solutions are possible.
Motors:
Flameproof enclosure d
Increased safety e
Non-sparking n
Gear Units:
Constructional safety c
Liquid immersion k
Flameproof Enclosure “EEx d”
Flameproof motors are designed with stronger walls
and specifi c ignition gaps to prevent internal explo-
sions from transmitting to the surrounding atmo-
sphere. Flameproof motors are frequently used for
inverter operations, brakes, encoders and when a
very high degree of safety is required. Specifi cally
fl ameproof motors:
• Have housings that can withstand internal explosion
pressures
• Have ignition gaps designed to dissipate the pressure
arising from an internal explosion
• Are designed so that generated hot gases are
signifi cantly cooled by the time they escape the
motor body so they do not potentially ignite the
potentially explosive environment
Increased Safety “EEx e”
Increased safety motors are designed with higher
quality insulation and larger clearances between ro-
tating parts. This prevents sparking as well as high
surface and internal temperatures even during motor
malfunction. Increased safety motors are less expen-
sive than fl ameproof motors, but use special windings
that generally result in lower performance than
fl ameproof motors.
Non-Sparking “EEx n”
Non-sparking motors resemble increased safety “e”
motors, but do not achieve the same protection level.
They do however have the same power output of
fl ameproof motors and can be used in conjunction
with approved inverters.
Constructional Safety “EEx c”
Construction safety for gear units takes into account
measures including ignition protection from hot sur-
face temperatures, sparks, moving parts and adiabat-
ic compression even under expected gear unit fail-
ures. NORD provides gear units with constructional
safety protection.
Liquid Immersion “EEx k”
Liquid immersion protection type “k” ensures partial
or complete submersion in a protective fl uid or con-
stant wetting of a potentially combustible surface.
ATEX Temperature Specifi cation
In a dust-air mixture surface temperature is a critical
thermal factor, therefore the maximum surface tem-
perature is declared based upon the dust type that is
present. The goal is to keep surface temperatures be-
low the smoldering and ignition temperature of a
dust-air mixture. NORD displays a maximum surface
temperature on the reducer nameplate, typically
125ºC.
Gas-air mixtures are grouped into temperature class-
es. The following table shows the maximum surface
temperature and temperature ignition ranges and
the for each temperature class.
Temperature
Class
Maximum Surface
Temperature ºC
Ignition
Temperature ºC
T1 450 > 450
T2 300 300 … 450
T3 200 200 … 300
T4 135 135 … 200
T5* 100 100 … 135
T6* 85 85 … 100
* Not satisfi ed with AC gear drives
ATEX
Information