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Tedeco Products

Lubrication System Diagnostics - Introduction

Duplex Debris Monitor | Electric Chip Detectors
Quantitative Debris Monitors | Cyclonic Debris Monitors

Lube system components, particularly rolling element bearings and gears, will generate magnetic particles in certain predominant, commonly occurring, failure modes, primarily spalling and skidding. Oil debris monitors, such as magnetic particle collectors and sensors, have long been used to detect failure onset in critical applications, particularly where undetected failures can lead to safety problems or economic loss. Over 50 years' experience in providing lube system failure detecting sensors for aerospace, marine, power generation and industrial applications, has provided Tedeco with a wealth of applications knowledge and a broad array of products to suit almost every monitoring need. In certain instances, for example, it may be possible to sense and collect these particles for visual examination and laboratory analysis, without interference with system operation.

On-Line Debris Monitoring has been successful in many critical lubrication system diagnostic applications, primarily due to its ability to overcome the shortcomings of other techniques. It is so reliable for predominant gear and bearing failure modes, for example, that its use on helicopter gas turbine engines and gearboxes has been mandated by federal authorities for over 30 years! Sensor technology advancement has resulted in the increased reliability of this instrumentation, particularly when used with the traditional techniques previously discussed.

Tedeco on-line lube debris monitoring components are grouped by sensor technology, presented in increasing levels of sophistication, magnetic chip collectors, electric chip detectors and quantitative debris monitors (QDM); all sensors are available with self-closing valves to permit removal; for particle retrieval, inspection and analysis, with minimal loss of oil.

Also presented are standard fittings for sensor mounting, to enhance sensor efficiency in particle capture and indication, such as the Lubriclone Cyclonic Debris Monitor and Duplex Debris Monitor.

1. Spalling

Spalling occurs as a result of sub-surface cracks in gear teeth or bearing rollers, balls or races which propagate just under the work hardened surfaces; where these microscopic cracks intersect the surface, flakes begin to form. The flakes are generated in very small quantities, early in the failure cycle. The flakes themselves leave behind a relatively "rough" surface patch, (the “spall”). Eventually, the further working of the bearing elements contribute to undermining of the spall circumference, resulting in further flake generation and growth of the spall itself. Failure to halt this process will eventually result in cracked ball, roller, cage or race and potential catastrophic failure.

2. Bearing Cage Failure

Bearing cage failure results from overloaded bearings, misalignment, excessive heat, particulate contamination or poorly toleranced components. Whatever the cause, small fractures result in bending, melting or cracking of the bearing cage, leading to generation of ferrous and non-ferrous debris. Early detection of these particles could prevent the bearing cage from catastrophic failure.

3. Skidding

Skidding results from lightly loaded bearings or poorly toleranced bearing components where there is a type of sliding motion between the balls/rollers, raceway and cage. This can generate very fine, almost "chalk-like", debris particles that grind away at the bearing element surfaces. Eventually, this grinding results in a loss of tolerance sufficient to cause the ball/rollers, to begin "squirming" and tumbling within the raceway, generating even more, and larger, particles, from the balls/rollers, the raceway, and the cage. If not stopped at this point, seizure of the bearing and subsequent catastrophic failure will occur.

Please contact us for free literature or to discuss your early-failure detection needs.

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