Siemens 1MB115 Installation And Maintenance Manual page 119

6.1.2 Hybrid mixtures
!
Explosion hazard from hybrid mixtures
Hybrid mixtures are mixtures of flammable dusts with explosive gas/
air atmospheres which can together create a dangerous explosive
atmosphere if they occur at the same time. Changes can arise in the safety
characteristics here, such as a change in the zonal classification, increase
in the explosion pressure, reduction in the minimum ignition energy and a
reduction in the maximum temperatures to be observed.
An explosion can result. This can result in death, serious injury or material
damage.
• For this reason, the relative characteristics must be considered both for
• Motors with dual plates for G ( "Gas" ) and D ( "Dust" ) may only be used
6.1.3 Motor overheating caused by dust
!
Explosion hazard due to overheating of the machine caused by a layer
of dust
Layers of dust thicker than 5mm can insulate the machine, resulting in
overheating. The maximum surface temperature of the machine cannot be
adhered to. The dust can ignite, resulting in an explosion. This can result in
death, serious injury or material damage.
• Dust the machine regularly.
• Do not allow dust layers thicker than 5 mm to build up on the machine
• Do not switch the machine on until the dust has been removed.
DANGER
gas (zones 0, 1 and 2) and for dust (zones 20, 21 and 22) where hybrid
mixtures arise. It is necessary for a competent assessor to determine in
the individual case whether the parameters determining ignition are
unfavorably affected in a particular hybrid mixture.
where these two occur after prior examination of the properties of the
hybrid mixtures by the user.
WARNING
surface.
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