Use These Keys to Achieve Effective Balancing

Proper installation procedures can eliminate a number of machinery defects and associated problems early. Aligning equipment to the correct tolerances and true targets and balancing it correctly at the time of installation—before the equipment is put into service—can eliminate the root cause of many bearing, rotor, seal, and coupling failures.

Proper installation procedures can eliminate a number of machinery defects and associated problems early. Aligning equipment to the correct tolerances and true targets and balancing it correctly at the time of installation—before the equipment is put into service—can eliminate the root cause of many bearing, rotor, seal, and coupling failures.

Looking for keys to successful dynamic balancing of your plant’s equipment? Use the following eight points from Ludeca Inc.’s (Doral, FL) Gary James. More important, include them as must-do elements in your balancing procedures.
—Jane Alexander, Managing Editor

— Inspect the equipment structure/mounts to make sure no cracks or loose bolts are present.

— Confirm that the belt on belt-driven equipment is in good condition and properly tensioned. (Remember that the second harmonic of a belt frequency can be very close to the rotational speed of the drive.)

— Inspect the rotating element for build-up and clean as necessary. (Remember that even a slight dust build-up can cause an unbalance.)

— If the equipment’s rotating element is a blower, count the number of blades. (Since correction weights must frequently be attached to blades, it may be best to use a fixed-location balancing method.)

— If equipment is down when you arrive, replace the reflective tape or attach new tape as required. (This ensures accurate phase data.)

— If possible, when acquiring your initial phase data, turn off the averaging function and monitor the data for a brief time to ensure stability. Doing this could identify potential problems.

— Document, document, document. That means keeping written notes on your findings with regard to:

• phase and amplitude data
• number of blades
• correction locations
• when weights were attached or removed
• how much weight was attached or removed
• sensor placement
• tachometer placement.

— If the equipment is variable speed, with a variable-frequency drive (VFD) or DC drive, make sure the speed is repeatable to within 5% or less, run to run. MT

For more information on balancing and alignment issues, visit ludeca.com.