38 | Flameproof motors
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- Clean the ribs in the frame for ribbed cooled
motors.
- Clean the heat exchanger for tube cooled
motors.
- All flameproof joints, after have been exposed
shall be covered with a corrosion inhibiting
grease (guarantee that they are free of rust
corrosion).
DANGER
In any circunstance, flameproof
motors can be operated in a
potentially
explosive
gas
atmosphere with an external surface
temperature above the certification
limit (ex. T4)
DANGER
In any circunstance, flameproof
motors for mining can be operated
in
a
potentially
explosive
atmosphere with an external surface
temperature above 150 ºC (on any
surface where coal dust can form a
layer) or 450º (where coal dust is not
likely to form a layer).
DANGER
In any circunstance, flameproof
motors can be operated in a
potentially
explosive
dust
atmosphere with an external surface
temperature above the certification
limit (ex. T135ºC).
LUBRICATION
8.2.1. GREASE LUBRICATED BEARINGS
The purpose of this maintenance is to lengthen
bearing life.
Depending on the application, load, speed,
temperature conditions and size, WEG motors may
be supplied with antifriction bearings lubricated by
grease.
Motor noise should be measured at regular
intervals from one to four months in order evaluate
the bearings conditon. A well-tuned ear is perfect
capable of distinguishing unusual noises, even with
rudimentary tools such as a screwdriver, etc. For a
more
reliable
analysis
of
the
bearings,
sophisticated equipment is required.
ATTENTION
Bearing temperature control is also
part of routine maintenance. Max.
absolute temperature shall not exceed
100ºC
(Absolute
temperature
=
temperature
rise
+
ambient
temperature).For
an
ambient
temperatuer of 40ºC, the temperature
rise of the bearings should not exceed
60K
Constant temperature control can be done by
means of external thermometers or by embedded
thermal elements.
ATTENTION
Alarm and tripping temperatures for
ball and roller bearings must be set for
110ºC and 120ºC respectively.
ATTENTION
Alarm and tripping temperatures for
sleeve bearings must be set for 100ºC
and 110ºC respectively.
ATTENTION
The alarm temperature should be set
at
10°C
above
the
working
temperature, not exceeding the limit of
110°C.
WEG motors are normally supplied with grease
lubricated ball or roller bearings.
Bearings should be lubricated to avoid metallic
contact of the moving parts, and also for protection
against corrosion and wear. In the course of time
and due to mechanical operation there is
deterioration of the lubricant properties and,
furthermore,
all
lubricants
are
subject
to
contamination under working conditions. For this
reason, lubricants must be renewed or replaced
from time to time.
NOTE
Protect the environment! The old
grease shall be correctly disposal.