MEASURING POSITIONAL CHANGE By LUDECA, INC.

Positional Change  After startup, machines grow warmer or colder, undergo thermal gradients, and may suffer dynamic load shifts.  This may cause their shaft centerlines to move from the position they were in when stopped.  Therefore, a good shaft alignment done when cold and stopped may result in a poor alignment when the machines are running and under load! Do you need to know if this is happening to your machines?

ObjectivesObjectives objective alignment targets  Your objective is to find out if your machines move between the stopped condition and the running condition, in order to establish good alignment targets.  The machines can then be misaligned to these alignment targets when ‘cold’ and stopped to compensate for the measured change.

Understanding what you need Measurement Measurement allows you to compare data at two different points in time with no knowledge of the intervening events which may impact the data. Monitoring Monitoring allows you to establish the trend of a change over time and observe the influences of given events.

Determining Positional Change four There are several ways to determine positional change. We will only discuss the following four:  Calculating “TLC” method  Calculating the changes theoretically from the observed changes in temperature using the “TLC” method.  Checking “Hot Alignment Check”  Checking the difference in the results from two separate rotational readings on the shafts, both taken stopped, one “cold”, and one right after shutdown “hot”. This is the so-called “Hot Alignment Check”.  Measuringrotational M 3 (Measuring Machine Movement) Brackets  Measuring the change with two separate rotational readings with special brackets mounted on the bearing housings, one taken hot and running, one taken cold and stopped, using the M 3 (Measuring Machine Movement) Brackets.  MonitoringPERMALIGN ®  Monitoring the change continuously with PERMALIGN ®.

The “TLC” calculation method The “TLC” method only looks at the theoretical projected growth from changes in temperature. TLC = T × L × C, where: T =  in Temperature, L = Length, C = Coefficient of Expansion  Positional shifts due to dynamic load are not considered.  Cooling influences of fans, and influences on machine shape of thermal gradients from process flows are not considered.  Unless specifically factored in, the expansion or contraction of connected piping will not be considered.

The “hot alignment check” The ‘hot check’ results will not be the same as that of the running machines because the machines are not running!  Positional shifts due to dynamic load are gone.  Too much time will elapse in locking out the machines, removing the coupling guard, setting up the system and taking readings. The temperature is quickly changing from what it was when the machines were running, so they are contracting or expanding, changing the alignment.  Process flows and cooling fans have stopped. This means thermal gradients have shifted, again changing the shape of the machines and their alignment. The same may apply to connected piping.

The M 3 Bracket

The M 3 Brackets The M 3 Brackets can be used with: ROTALIGN ® /PRO, SMARTALIGN ®, OPTALIGN ® PLUS and MASTERLIGN ® /BASIC ROTALIGN ® /PRO, SMARTALIGN ®, OPTALIGN ® PLUS and MASTERLIGN ® /BASIC Laser Shaft Alignment Systems The M 3 (Measuring Machine Movement) method:  Mount the M 3 brackets on the bearing housings of the machines.  Take a rotational reading when machines are cold and stopped.  Take another while they are running under load.  Compare the results. Any difference means positional change may have taken place.

Measuring with the M 3 Brackets

M 3 Brackets – Limited Monitoring Limited Continuous Monitoring with ROTALIGN ® /PRO:  If conditions are stable, ROTALIGN ® /PRO allows you to monitor positional change continuously in both planes with its Move Function, because of its unique five-axis sensor.  This capability eliminates the need to take rotational readings and remove and replace the components between the hot and cold readings, helping to control data quality.  You can also store and annotate the data in the Measurement Table.  Adjustable averaging in the Move Function helps limit the influence of vibration and heat on the readings.

PERMALIGN ®

Why monitor with PERMALIGN ® ? PERMALIGN ® only PERMALIGN ® is the only laser-based positional change monitoring system.  Quality assurance  Quality assurance of data.  Completeness of data.  Trending of data over time.  Full documentation capability.

PERMALIGN ® ’s unique features  PERMALIGN ® ’s patented concentric reflected beam technology is impervious to any influence on beam movement from heat waves or particles in the path of the beam.  Its components are thermally stable. They will not distort with temperature changes, so the beam will not be moved.  The laser transducer and prism are specifically designed to withstand heat and vibration over time.  PERMALIGN ® permits you to establish precisely which machine is moving, how much and which way.  In the event any bracket movement occurs, you can determine this from the data collected and trended with WINPERMA ® software and correct for it.

What about extreme heat? PERMALIGN ® components can be air-cooled or cooled by running tap water through cooling tubes.