Application Note

Fluke Corporation
PO Box 9090, Everett, WA 98206 U.S.A.
Fluke Europe B.V.
PO Box 1186, 5602 BD
Eindhoven, The Netherlands
For more information call:
In the U.S.A. [phone] or
Fax [phone]
In Europe/M-East/Africa [phone] or
Fax [phone]
In Canada (800)-36-FLUKE or
Fax [phone]
From other countries [phone] or
Fax [phone]
Web access: http://www.fluke.com
©2014 Fluke Corporation.
Specifications subject to change without notice.
Printed in U.S.A. 10/2014 6003638b_en
Modification of this document is not permitted
without written permission from Fluke Corporation.
Fluke. Keeping your world
up and running.
®
3 Fluke Corporation Temperature and vibration send maintenance signals
Effects of machine faults
The effects of faults identi-
fied by vibration can be severe.
Unchecked machine faults can
accelerate rates of wear (i.e.
reduce bearing life), damage
equipment, create noise, cause
safety problems, and degrade
plant working conditions. In the
worst cases, a fault can knock
equipment out of service and halt
plant production.
Measured and diagnosed cor-
rectly, vibration can be used in a
preventive maintenance pro-
gram as an indicator of machine
condition, and you can target
remedial action before disaster
strikes.
The handheld Fluke 810
Vibration Tester is designed
and programmed to diagnose
the most common mechanical
problems of imbalance, loose-
ness, misalignment, and bearing
failures in a wide variety of
mechanical equipment, including
motors, pumps, fans, blowers,
and more.
The Fluke 810 quickly detects
vibration along three planes
of movement, then provides
a plain-text diagnosis with a
recommended solution. The
diagnostic technology in the
Fluke 810 analyzes machine
operation and identifies faults by
comparing vibration data to an
extensive set of rules developed
over years of field experience.
It’s all done with the intelligence
built into the tester, without the
long-term monitoring, recording,
and analysis required for typical
long-term vibration monitoring
programs.
An ideal solution
It was the ideal solution for the
area logistics manager for a
major oil company. For the past
year he’s been using the Fluke
810 Vibration Tester to diagnose
issues in pumps, blowers and
motors up to 3,500 horsepower
that pump 8,000 barrels an hour.
“This is something I’ve been
waiting on,” he said. “The neat
thing about it is the Fluke will
give you its idea of what it
thinks is wrong.” he said. “But it
also gives you that signature you
can give to the engineers.
“We went down to our trans-
port station and were able to find
some bearing problems on one of
our units,” he said. The Fluke 810
“called out for a bearing problem.
Once we got the pump into the
shop we found out the shaft was
out of round, which took the bear-
ing out.”
Ease of use is another advan-
tage. “You can give this thing to
just about anybody, and they can
learn how to use it in a matter of a
few minutes. You can log all your
equipment, you can pair it up with
Fluke’s infrared camera and it will
give you a full picture.”
Used together with a Fluke
infrared camera, the Fluke 810
delivers results fundamental to the
company maintenance program.
“With the big motors, we do the
vibration analysis, we look every-
thing over on an annual basis with
the Fluke imager so we can see if
there’s any heat rise, and we use it
on all the switch gear,” he said. “I
call it shoot—fix—move on.”
Characteristics of vibration
To understand how vibration shows
up, consider a simple rotating machine
like an electric motor. The motor and
shaft rotate around the axis of the
shaft, which is supported by a bear-
ing at each end. One key consideration
in analyzing vibration is the direction
of the vibrating force. An imbalance
would most likely cause a radial vibra-
tion as the “heavy spot” in the motor
rotates. A shaft misalignment could
cause vibration in an axial direction
(back and forth along the shaft axis),
due to misalignment in a shaft coupling
device.
Another key factor in vibration is
amplitude, or how much force or mag-
nitude the vibration has. The farther
out of balance a motor is, the greater
its amplitude of vibration. Other factors,
such as speed of rotation, can also
affect amplitude. As rotation speeds up,
the imbalance force increases.
Frequency patterns in the data can
be related to machine fault templates.
By looking at the patterns, the user can
identify the source of the vibration and
therefore the machine fault. Examples
of this include: motor shaft, compo-
nents in the roller bearing, fan blades,
gear teeth, and pump vanes.
Frequency refers to the oscilla-
tion rate of vibration, or how rapidly
the machine tends to move back and
forth under the force of the condition
or conditions causing the vibration.
Frequency is commonly expressed in
cycles per minute or hertz (CPM or Hz).
One Hz equals one cycle per second or
60 cycles per minute.
Even a simple motor could be vibrat-
ing in multiple directions (radially and
axially), with several rates of ampli-
tude and different frequency patterns.
Imbalance vibration, axial vibration,
and vibration from deteriorating roller
bearings could combine to create a
complex vibration spectrum.