Case Analysis & Practical Application Flashcards

A conveyor drive gearbox operating in a food processing plant shows elevated iron particles in oil analysis. The plant requires H1-rated lubricants. Which corrective action is most appropriate?

Answer: Switch to a higher-viscosity H1-rated gear oil and monitor wear trend

Selecting a higher-viscosity H1-rated gear oil addresses the wear trend while maintaining food-safety compliance, and monitoring confirms whether the change is effective.

An electric motor bearing running at 3600 RPM is being re-greased. The technician notices the grease fitting is packed solid with hardened grease. What is the best first step?

Answer: Clean and clear the fitting before introducing fresh grease

A blocked fitting must be cleared first so new grease actually reaches the bearing; forcing grease through a blockage can over-pressurize seals.

Oil analysis on a hydraulic system reveals a particle count of ISO 23/21/17. The system specification calls for ISO 16/14/11 cleanliness. What action should be taken?

Answer: Flush the system and pass fluid through a kidney-loop filtration unit until target cleanliness is reached

Offline (kidney-loop) filtration is the most effective method to rapidly reduce particle counts to the target ISO cleanliness code.

A plant engineer notices that two similar compressors have very different oil consumption rates. Compressor A uses twice the oil of Compressor B despite identical operating hours. What is the most likely root cause to investigate first?

Answer: Compressor A has worn piston rings or valve seals causing oil carry-over

Worn piston rings or valve seals allow oil to pass into the gas stream, dramatically increasing oil consumption in reciprocating compressors.

During a lubrication audit, a technician finds that multiple lube routes mix NLGI 2 lithium-complex grease and NLGI 2 polyurea grease in the same bearing housings. What is the primary concern?

Answer: Incompatible thickener systems can cause grease softening and loss of lubrication

Lithium-complex and polyurea thickeners are often incompatible, and mixing them can cause the grease structure to collapse, leading to lubrication failure.

A plant switches from mineral oil to a polyalkylene glycol (PAG) fluid in a worm gear drive. What precaution is most critical before filling?

Answer: Thoroughly flush residual mineral oil because PAG and mineral oil are immiscible

PAG fluids are incompatible with mineral oils and will form sludge if mixed, so thorough flushing is mandatory before filling.

Vibration analysis on a pump bearing shows a spike at bearing defect frequency corresponding to the outer race. Oil analysis shows no elevated metals. Which lubricant-related issue should be investigated?

Answer: Inadequate grease quantity leading to inadequate film formation on the outer race

An outer-race defect without metallic wear particles suggests inadequate film thickness rather than active corrosive wear, pointing to insufficient lubrication.