Siemens SINUMERIK 808D ADVANCED Training Manual page 50

Commissioning
of Prototype
Machine using
Sample PLC
Electrical cabinet design
Correct installation of fans
For cabinets it is possible that the cooling can be achieved with fans
drawing air from the outside via a filter. Natural convection causes the
warm air to exit via a filter.
The fact that air is being drawn directly from the outside means that this
system can never be airtight. Having a fan for the inlet side only ensures
that the cabinet is positively
pressurised which helps keep
contaminants from entering.
It is extremely important that
the filters are service regularly
to avoid ingress of
contaminants and to maintain
the efficiency of the cooling
process.
Fan & filter type cooling
system
Commissioning Guide
Step 10
Outlet
via filter
Drive
equipment
Temperature
Measuring points
Inlet via
Fan &
filter unit
Correct installation of cooling units
The cool air should be directed to the bottom of the drive. The natural
convection will draw the air through the drives.
The cool air from the cooling unit should not be directed straight onto/into
the drives, it should be allowed to mix with the warmer air already in the
cabinet, this will minimise the risk of condensation forming.
Cabinet top mounted
cooling units require
a method of directing
the cool air from the
cooling unit to the
bottom of the drives.
In the case of a door
mounted unit it may
be necessary to
direct the cool air
with the use of a
baffle.
Cabinet door
mounted cooling unit.
Page 50
s
≥ 200mm
Drive
equipment
Baffle
Temp.
Meas.
point
808D ADVANCED Turning and Milling
Outlet
Cooling
unit
Inlet