Application Note

2 Fluke Corporation Temperature and vibration send maintenance signals
What to look for
Use your handheld infrared
camera to look for hot spots, cool
spots and other anomalies. Be
especially aware of similar kinds
of equipment operating under
similar conditions but at differ-
ent apparent temperatures. Such
deviations might signal problems.
A good approach is to create
inspection routes that include
all critical assets. Each time
you inspect a piece of equip-
ment, save a thermal image of it
and the associated data on the
computer and track its condi-
tion over time. That way, you’ll
have a baseline for comparisons
that will help you determine
whether a hot spot (or cool
spot) is unusual. You’ll also be
able to verify when repairs are
successful.
Whenever you use a infra-
red camera and find a problem,
use the associated software to
document your findings in a
report that includes a digital
photograph as well as a thermal
image of the equipment. That’s
the best way to communicate the
problems you find and to suggest
repairs.
Many Fluke infrared cameras,
like the Ti400 have both IR-
Fusion technology, IR-PhotoNotes
photo annotation and voice
recording to make communica-
tion effective and easy.
When vibration indicates
a problem
Vibration isn’t the cause of the
problem it is the indication that a
problem exists. Vibration can be
normal in machine operation—or
it can be a sign of trouble. Most
industrial devices are engineered
to operate smoothly and AVOID
vibration, not produce it. In
electric motors, rotary pumps and
compressors, fans, and blow-
ers, low vibration is the ideal. In
these machines, vibration can
indicate problems or deterioration
in the equipment. If the underly-
ing causes are not corrected, the
unwanted vibration itself can
cause additional damage.
But how can the plant
maintenance professional tell
acceptable, normal vibration
from the kind of vibration that
requires immediate attention,
to service or replace troubled
equipment?
Common causes to look
for in machine vibration
• Imbalance – A “heavy spot”
in a rotating component
will cause vibration when
the unbalanced weight
rotates around the machine’s
axis, creating a centrifugal
force. The cause could be a
manufacturing defect or a
maintenance issue. Imbalance
can severely reduce bearing
life and cause undue machine
vibration and heat.
Rising heat becomes
visible with a Fluke Ti400
Infrared camera, which
captures infrared images
of the apparent surface
temperatures of all types
of equipment.
• Misalignment/shaft runout –
Angular misalignment occurs
when the axes of a motor and
pump are not parallel. When
the axes are parallel but not
exactly aligned, that’s parallel
misalignment. Misalignment
may be caused during assem-
bly or develop over time, due
to thermal expansion, com-
ponents shifting, or improper
reassembly after maintenance.
The resulting vibration may
be radial or axial (in line with
the axis of the machine) or
both. Misalignment can cause
coupling wear and failure.
• Wear – As components such
as bearings, drive belts or
gears wear, they may cause
vibration. When a roller bear-
ing race becomes pitted, for
instance, the bearing rollers
will cause a vibration each
time they travel over the dam-
aged area.
• Looseness – Vibration that
might otherwise go unnoticed
may become obvious and
destructive if the component
that is vibrating has loose
bearings or is loosely attached
to its mounts. Looseness can
allow any vibration present
to cause wear and fatigue in
bearings, equipment mounts,
and other components.