August 26, 2015
Performing Alignment Checks as Part of Your Preventive Maintenance.
By James Pekarek
A systematic preventive maintenance plan is crucial to the operation and reliability of rotating equipment in factories and power plants. In addition any building or company that has HVAC equipment, water and sewer systems or hydraulic systems requires people with good mechanical skills to keep the rotating machinery running.
Most preventive maintenance programs include pump oil level checks, greasing motor bearings, checking reservoir levels in automatic lubrication systems and a host of others for specific equipment. Another important preventative maintenance item that is very often overlooked is checking the shaft alignment of said rotating equipment.
Maintaining precision shaft alignment of rotating equipment is very critical to the proper operation, reliability, and longevity of the equipment. Unfortunately this simple step is very often overlooked. In my training classes one question I ask of the technicians is “how often do you perform shaft alignment checks”. The most common answer is “usually only when something fails”. The second most common answer is “maybe once or twice a year”.
So why not incorporate a precision shaft alignment check into your periodic maintenance procedures? Studies have shown misalignment is the cause of 50% to 70% of rotating equipment failures! Including a precision laser alignment check takes very little time to perform, 5 to 10 minutes after the coupling guard is removed. (and lock out/tag out)
This small step could uncover a potential problem that will cost hundreds or thousands of dollars in unscheduled downtime and equipment repairs. You already have the alignment equipment, why not use it?
The VibrAlign Trainers have performed training at companies where machines have been running out of alignment for years and they just continually replace the coupling inserts and pump seals as this is “normal”.
During a Fixturlaser NXA Pro training class at a factory in California, we checked the alignment of a machine they claimed is running fine “it’s just very hard on the rubber inserts, so we replace them about twice a month”.
The mechanics mounted the NXA Pro for an alignment check which took about three minutes. The initial results showed the vertical offset to be +42.0 mils with a horizontal angularity of 0.16 mils/inch. (1.0 mil = .001”). The vertical offset was 21 times the allowable tolerance with the horizontal angularity more than 3 times tolerance!
We completed a precision laser shaft alignment in about 15 minutes with these final results.
As you can see the alignment numbers are well within the 3600 RPM tolerance. The technicians were actually surprised at how quiet the system ran afterward!
Had they incorporated a quick alignment check into their preventive maintenance procedure, this problem would have been discovered years ago saving thousands of dollars in couplings, man-hours, and lost time, just for a 20 HP motor connected to a little water pump.