Application Note

Using the SKF Machine Condition Advisor in a successful grease lubrication programBy Torsten Bark • SKF Reliability Systems

BenefitsSimple application makes monitoring easy for non-experts•Helps prevent over- and under-lubrication•Provides advice on machine condition•Measures machine vibration and temperatures•Assists in reducing the number of machine repairs•Helps to avoid costly unplanned downtime due to early warnings•

Typical applicationsRotating equipment lubrication programs•Fans, pumps, motors•

Do you want to improve your grease lubrication program?

The SKF Machine Condition Advisor is an essential tool used to successfully detect machinery vibration problems; however, one of the most valuable and often understated uses of this simple tool is the monitoring of grease lubrication programs.

Lubrication and bearing failureRolling contact bearings can fail due to over lubrication as well as lack of lubrication. In many industrial environments, the grease lubrication program is virtually unmonitored. Operators are not aware that over greasing (typically using the grease gun) can destroy bearing seals, permits introduction of contaminants and unwanted solvents and introduces so much grease into the bearing that heat transfer and friction reducing design characteristics are dangerously disrupted. Following is a method which will improve the quality of a grease lubrication program in virtually any industrial application.

The SKF Machine Condition AdvisorThe new SKF Machine Condition Advisor is simple to use and has many benefits. When held against the machine surface at bearing locations, the SKF Machine Condition Advisor simultaneously provides three measurements – overall velocity, enveloped acceleration enveloping and infrared temperature measurement.

Its size and rugged nature make the SKF Machine Condition Advisor well suited to supplement any tool box, or it can be easily carried in the pocket of the lubricator, mechanic, or the floor supervisor.

The SKF Machine Condition Advisor’s vibration velocity measurement is designed to detect general machine faults such as unbalance, misalignment and mechanical looseness.

The SKF Machine Condition Advisor compares the velocity readings to ISO guidelines (International Organization for Standardization 10816-3) and displays an “A” for Alert or “D” for Danger when measurements exceed these guidelines.

Guidelines do not substitute for experience and good judgment. The most reliable method of determining alarm conditions is to trend the SKF Condition Advisor vibration readings over time, establish baseline values and set alarm levels above baseline values.

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The SKF Machine Condition Advisor offers a versatile evaluation since it contains the overall velocity measurement, the overall enveloped acceleration value (gE) and an infrared temperature measurement.

Commonly, higher than normal enveloped acceleration readings provide early indication of bearing failure.

Temperature measurements enhance the early warning benefit of the instrument by offering indication of the mechanical condition or the load applied to a specific component. As a bearing or its lubrication fails, increased friction causes temperature to rise.

The ProcedureWith proper use, the SKF Machine Condition Advisor can be a valuable tool for managing a grease lubrication program. The following general procedure is recommended:

If the bearing exhibits a low amplitude velocity measurement •(<0.25 ips derived peak/4.5 mm/s RMS, for example), but has a relatively high enveloped acceleration overall (>1.0 gE), inadequate lubrication may be the cause.Using a grease gun, apply a single shot of grease into the bearing •grease nipple.Take another set of measurements. If the enveloped acceleration •level remains high, repeat the above step, checking the enveloped acceleration vibration level after each shot of the grease gun. The first time a drop in the enveloped acceleration measurement is observed, stop pumping grease to the bearing.

After the machine has been in operation for a full shift, repeat the •enveloped acceleration measurement. If vibration levels have not increased, the job is complete. Do not apply any further lubrication until the enveloped acceleration level increases again.

If the enveloped acceleration level has increased over the shift to previous levels, further diagnostic analysis should be performed.

Proper lubrication of rolling element bearings is absolutely essential. Over lubrication of rolling element bearings can drastically reduce bearing life. Proper usage of the SKF Machine Condition Advisor can make the difference between a successful grease lubrication program and repeated machine failure.

Cost saving of machine repair – parts (estimate, average) …… $1,950Cost saving of machine repair – labor (estimate, average) ………. $500Total cost savings per machine …………………………………. $2,450

Savings per machine by eliminating downtime not considered.

Number of machines measured per month ………………………………… 40Number of machines measured per year …………………………………. 480Percentage of machine saved (estimate) …………………………………….. 3%Number of avoided downtime per year ………………………………………. 14Total savings per year (14 times $2,450) ………………….. $34,300

Investment in SKF Machine Condition Advisor …………………….. $1,690Labor time increase for measurements per year ………………… $4,800Total investment per year ………………………………………… $6,490

Total savings per year …………………………………………… $27,810

Return on Investment ROI ………………………………………….. 428%

Please contact: SKF Reliability SystemsSKF Condition Monitoring Center – San Diego5271ViewridgeCourt•SanDiego,California92123USATel:+1858-496-3400•Fax:+1858-496-3531Web Site: www.skf.com/cm

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© SKF Group 2010The contents of this publication are the copyright of the publisher and may not be reproduced (even extracts) unless prior written permission is granted. Every care has been taken to ensure the accuracy of the information contained in this publication but no liability can be accepted for any loss or damage whether direct, indirect or consequential arising out of the use of the information contained herein. SKF reserves the right to alter any part of this publication without prior notice.

PUB CM3129 EN · June 2010