2. Continuous laser monitoring system: Permalign laser monitors and reflectors from Ludeca (www.ludeca.com) were installed in standard configuration. A biaxial photo detector gives measurement resolution of 1 micron, and system accuracy is better than 2% of displayed value.
3. Periodic laser measurement of casing position: A standard laser shaft alignment system (Rotalign Pro from Ludeca) was used on a bracket to obtain periodic relative positions between machine assembly casings. Sensor resolution is 1 micron and 10 micro-radians. Displayed values are accurate to within 2%.
The unit was taken offline two days before installing instrument bracketing and monuments to be sure the metal casing reached ambient temperature.
Offline positional data was recorded using standard methods. The continuous laser monitoring system was initiated to automatically record alignment changes every 10 seconds throughout the measurement cycle.
The motor was energized and brought to full load. Heat soak conditions were achieved after about four hours of operation. Periodic laser measurements and optical data were collected at this time to serve as the stable online position.
Specifications verified
Table 1 compares the various measurement methods to each other and to the manufacturer's recommended cold alignment target.
Differences recorded generally fall within the tolerance range for this category of equipment with the exception of the manufacturer's horizontal alignment targets. Notwithstanding this exception, it was determined that adherence to the manufacturer's alignment targets should not have been sufficient to cause the experienced level of premature bearing failures.
Most bearing failures are observed to occur on outdoor units. The agricultural products company is currently considering the following actions:
1. Determine seasonal alignment targets and increase frequency of machinery alignment to those targets.
2. Construct enclosures around all outdoor units and align to adjusted manufacturer's alignment target.
