In This Issue:

• Up Front: Quick Inspection Saves Motor Bearings

• Book Bits: How Particle Contamination Wreaks Havoc

• Today's Tip: Adjusting Air Line Oilers
  

• Q & A: Improving Oil Sampling Results
  

Up Front

Quick Inspection Saves Motor Bearings

I’ve made it a practice of checking the zerk fill holes in the endbells of new motors for obstructions and contaminants. In the last year, approximately four to five new motors had metal shavings in the holes – a result of tapping the holes. If these holes hadn't been checked, our lube pm’s would have pushed the metal shavings into the bearing, setting up a possible failure mode or premature failure.

We’ve also found that after having the endbells of refurbished motors bored and bushinged, there were shavings left in the bearing housing, zerk and purge holes. This was after a clean dip and bake and finding the endbells out of tolerance.

Submitted by Marty Nelson, JEA. Thanks Marty!

Each Up Front story published will earn the sender $50. To submit a case study, experience or lesson learned click here or e-mail mramsey@noria.com.

Book Bits

How Particle Contamination Wreaks Havoc

From "Oil Analysis Basics":

How particles affect the oil - Particles, especially catalytic metal particles like copper, iron and lead increase the rate at which oxidation occurs. Particles also strip the oil of its polar additives, including anti-wear additives, extreme pressure additives, rust inhibitors and dispersants. Also, numerous very small particles in stable suspension can cause the oil’s viscosity to increase.

How particles affect the machine - Abrasive particles are responsible for much of the wear leading to premature failure of mechanical components. Under sliding conditions, clearance-sized particles enter the oil film between surfaces and cut away material much like a lathe cuts metal. Under rolling contact conditions, particles transfer concentrated load between two surfaces in relative motion, resulting in surface fatigue, pitting, and spalling. Particle-contaminated oil traveling at high velocity can also cause erosive wear.

Click here for more information about "Oil Analysis Basics".

Today's Tip

• After installation of an air line oiler, ensure the drip rate is adjusted properly. This is normally accomplished by using a 1/16" diameter orifice at a fixed pressure. Example:

  10 PSI = 32 Minutes/Drop
  20 PSI = 16 Minutes/Drop
  30 PSI = 11 Minutes/Drop
  40 PSI = 8 Minutes/Drop
  50 PSI = 7 Minutes/Drop
  60 PSI = 6 Minutes/Drop
  70 PSI = 5 Minutes/Drop
  80 PSI = 4 Minutes/Drop
  90 PSI = 3 Minutes/Drop
  100PSI = 3 Minutes/Drop

  Also to be considered is the relationship between the Filter/Regulator/Oiler and the use of the proper oil specification. Air line oilers are often improperly adjusted. In some cases, they are not opened at all. (Tip submitted by Richard Evans, Plant Engineer, TECT-Utica. Thanks Richard!)

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Q & A

Improving Oil Sampling Results

"We have a quarterly oil sampling program at our mill on many of our critical systems. We have installed sampling ports on our hydraulic and oil circulation systems but rarely see an advance warning of equipment problems. Consequently we have unexpected failures on sampled systems. What can we do to improve our results?"

There are many factors that can influence the effectiveness of an oil analysis program, including test slate selection, alarm levels, laboratory quality, sample frequency, sample location and equipment operational factors to name a few. Two common problems that programs encounter include poor test selection and poorly selected sample port locations.

While both of these can confuse the outcome and minimize the effectiveness of analysis, a properly selected sample location is vital for trending changing equipment condition. It is possible to assess lubricant and contamination conditions with samples taken from many locations in most reservoirs. However, sampling for evidence of mechanical problems requires a sample to be collected from a location that contains the highest concentration of 'evidence' of a problem. The evidence is of course the wear metals.

Often samples are collected from a pressure line after a filter, or from a drain line toward the bottom of a reservoir. This is generally because these locations enable low cost installation, easy access and low cost sample collection. However, these common locations are far from ideal because the 'evidence' may be filtered or settled out of the lubricant, leaving the program with little more than fluid properties information. Sample ports must be configured to enable collection of lubricant in close proximity to the mechanical components in question.

We have heard the axiom about factors influencing real estate transactions: The top three factors in maximizing real estate value are Location, Location and Location. The same concept applies to oil analysis-based equipment condition monitoring programs.

Mike Johnson, Sr. Technical Consultant, Noria Corporation

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