Handbook Of Shaft Alignment Episode 2 Part 7 docx

____ Print machinery drive train side view configuration ____ Print machinery drive train top view configuration ____ Print side view alignment model ____ Print top view alignment model

Shaft alignment software questionnaire

1 Are you a manufacturer or author or programmer of shaft alignment software programs? Yes

No

2 Are you a distributor of shaft alignment software programs? If so, please list the names ortitles of the software programs and who the manufacturer or creator of shaft alignmentsoftware program is Please indicate the company, address, phone number, contact person,and Web site (if applicable) of the manufacturer or creator If you are a distributor only,skip the remaining questions

Distributor for:

Software title Manufacturer=Creator name _Address

P O Box.Suite _City State=Province _Zip=Postal code Country Phone # Fax # E-mail address _Web site Manufacturer or author or programmer questions only

3 Does your software run on widely used personal computers or does it require a customcomputer?

Operates on standard computers

Requires a custom computer

4 If it requires a custom computer, please list the manufacturers of the custom computer andthe cost of the unit

Manufacturer of custom computer Cost _(U.S dollars)

5 If the software works on widely used personal computers, what computer operatingsystems will the software run on?

6 If the software operates on a custom computer, can it interface with a widely usedpersonal computer?

Yes

No (skip questions 7 and 8)

7 If it does interface with widely used personal computers, what computer operatingsystems will it interface with?

Firewire

PCMCIA card, specify Memory card, specify _ WiFi

Price _ (U.S dollars)

10 What was the release date of the programs?

Release date: _

11 Minimum RAM required

12 Minimum screen pixel density _ 640480

Others, describe

13 Special graphics required?

Yes, describe _ No

25 Editable side direction?

39 Input asymmetric bracket sag?

53 Alignment Bar (Dyn-Align=Dodd) input?

80 Shows bracket sag amount?

94 Aligns C-flanged and vertical machinery?

105 Selectable items for printout?

Print machinery drive train side view configuration

Print machinery drive train top view configuration

Print side view alignment model

Print top view alignment model

Print current alignment readings

Print stationary–movable or laser data

Print bracket sag amount

Print OL2R data

Print current maximum alignment on tolerance guide

Print gaps and shim shapes for soft foot correction

Print vertical allowable movement envelope

Print lateral allowable movement envelope

Print help screens

Print vertical and lateral movement corrections

106 Hard copy (printed) software manual included?

110 What is your warranty period? _

111 What are the recommended calibration intervals, does the unit have to be sent back tothe factory for calibration, and what is the charge for recalibration?

114 If you have introduced new shaft alignment systems models, do the people who ownyour original models have the option to trade in their older models to upgrade to anewer model? If so, what is the cost of the upgrade?

Yes, cost _ No

115 What is the price (or price range) of the software programs?

Boiler and Machinery Engineering Report—Shaft Alignment for Rotating Machinery, Section 4.0,

#4.26, October 1989, American Insurance Services Group, Inc., New York

Brotherton M., Masers and Lasers, McGraw Hill, New York, 1964

Evans, G., Casanova, P., Azcarate, A.M., The Optalign Training Book, Ludeca Inc., Miami, FL, 1990,Catalog #01-705-01

Franklin, D.E., Active Alignment, presented at the 10th Biennial Machinery Dynamics Seminar,September 1988, The National Research Council, Canada

Hecht, J., The Laser Guidebook, McGraw Hill, New York, 1992

Laser Diode User’s Manual, Ref No HT519D, Sharp Electronics Corporation, 22-22, Nagaike-Cho,Abeno-Ku, Osaka, 545-8522, Japan

Mims, F.M III, Getting Started in Electronics, Tandy Corporation, Fort Worth, TX, 1993, Catalog #276–5003

Murray, M G., OPTALIGN—Laser—Optic Machinery Alignment System—Report Following FourMonth Test, April 2, 1985, Murray and Garig Tool Works, Baytown, TX,

Murray, M G., Selecting Alignment Instruments, Maintenance Technology, July–August, 1996.Optoelectronics Components Catalog, UDT Sensors Inc., 12525 Chadron Ave., Hawthorne, CA 90250

2003 Precision Alignment and Balancing Guide, Maintenance Technology 8.5-200311-23-F, November 2003.Techniques for Digitizing Rotary and Linear Motion, Encoder Division, 4th printing, Dynamics ResearchCorporation, Wilmington, MA, 1992

16 Measuring and Compensating for Off-Line

to Running Machinery Movement

Up to this point in the book, we discussed how to align rotating machinery when it is shutdown and hopefully in a very stable position Once the shafts are aligned within acceptabletolerances, the coupling engaged, and the machinery started up, changes in the positions ofthe shafts may begin to occur that could alter the accuracy of the alignment when theequipment is running

Virtually all rotating equipments will undergo a change in position during start-up and whilerunning that affects the alignment of the shafts The driver machine may move a certain amountand in a certain direction as it goes from an off-line to a stable operating condition The drivenelements of the system may move different amounts and in different directions In order for theshafts to run collinear under normal operating conditions, it is desirable to know the amountand direction of this movement to properly position the machinery during what is commonlycalled the ‘‘cold’’ (i.e., off-line or not running) alignment process to compensate for this change

16.1 WHAT TYPE OF MACHINERY IS LIKELY TO CHANGE EQUIPMENT’S POSITION WHEN RUNNING?

The OL2R movement characteristics of the vast majority of rotating machinery drive systems

in existence have never been measured Based on observations made on a relatively smallpercentage of drive systems currently operating, it appears that perhaps on 60%–70% of thedrive systems in existence, the amount of movement is negligible and can basically be ignored

In the remaining cases however, this movement can make all the difference between a free drive system and one that is plagued with problems It is important to know how muchmovement is occurring before you deem it insignificant and ignore it The most bafflingquestion is which rotating machinery do you have that is moving enough from OL2Rconditions where you need to measure and compensate for this movement

trouble-Below is a broad list of machinery that is likely to change its position enough from OL2Rconditions to warrant measuring this occurrence:

. Rotating machinery drive systems running at or above 200 hp and speeds of 1200 rpm orgreater

. Machinery that undergoes a change in casing temperature

471

For example:

(1) Electric motors and generators

(2) Steam turbines

(3) Gas turbines

(4) Internal combustion engines (diesels, etc.)

. Speed changers (e.g., gearboxes and fluid drives)

. Machinery that is pumping or compressing fluids or gases where the fluid or gasundergoes a change in temperature by 508 or greater from intake to discharge (thiscould be either a rise or drop in temperature) For example:

(1) Centrifugal or reciprocating compressors

expan-16.2 WHAT CAUSES MACHINERY MOVEMENT TO OCCUR?

There are a variety of factors that cause machinery to move once it is on line and running Themost common cause is due to temperature changes in the machinery itself (as it compressesgases or heats the lubricant from friction in the bearings) and is therefore generally referred to

as ‘‘thermal’’ or ‘‘cold’’ to ‘‘hot’’ movement The temperature change in rotating machinery israrely uniform throughout the casing, which causes most equipment to ‘‘pitch’’ at some anglerather than grow (or shrink) straight up (or down) For compressors, turbines, and pumps,thermal expansion (or contraction) of the attached piping may also cause the equipment

to shift

Other sources of movement in machinery can be caused by loose foot bolts, varyingweather conditions for equipment located outdoors, heating or cooling of concretepedestals, changes in the operating condition of equipment from unloaded to loadedpostures, or casing and support counterreactions to the centrifugal force of rotors as theyare spinning

Special alignment considerations must be taken into account for equipment that is startedand stopped frequently or where loads may vary considerably while running In cases likethese, a compromise has to be made that weighs factors such as period of time at certainconditions, total variation of machinery movement from maximum to minimum, couplingand alignment tolerances, etc To properly observe and record these changes, periodicchecks should be made of this change in movement to fully understand how to effectivelyposition the equipment to minimize any damaging effects from running misalignment.Continuous shaft position monitoring systems are available and are explained later inthis chapter

It has been my experience however that the majority of rotating equipment will typicallymaintain one specific position regardless of varying loads What usually turns out to be abigger problem is that some equipment may have to be offset aligned ‘‘cold’’ by a considerabledistance making start-ups very nerve wracking In the majority of cases, equipment willundergo the greatest rate of change of movement shortly after start-up ‘‘Shortly’’ can

mean anywhere from 5 min to 1 h for most types of equipments and may settle at some finalposition several hours, days, or even weeks later.

As equipment goes from a running to an off-line (R2OL) condition (i.e., coast down toshutdown), a wide variety of movement amounts and directions can occur Some equipmentmay make a very rapid change immediately after shutdown Other drive systems may flounderaround and then slowly move back near their original position To my knowledge, there hasnever been any published information where someone has observed several start-up andshutdown sequences to see if the machinery continues to attain exactly the same positions inthe off-line and in the running conditions Most people just assume and hope that this happens

16.3 CONDUCTING THE OFF-LINE TO RUNNING MACHINERY

MOVEMENT SURVEY

Observing the movement of rotating machinery may seem quite complicated at first glance,but these measurements are nothing more than a comparison between the position of thecenterlines of rotation when the machinery is off-line to the position of the centerlines ofrotation when the machinery is running, frequently referred to as off-line to running (OL2R)condition Therefore, data must be taken when the machinery is off-line (cold) and then againwhen the machinery is running (hot) It is also feasible to reverse the sequence of datacollection In other words, take measurement readings when the machines are running, shutthe machinery down, and take readings again (i.e., R2OL) In fact, it is recommended thatboth OL2R and R2OL measurements be taken just to see if the movement is consistent andrepeatable

There are many inventive ways to measure shaft alignment positions from OL2R (or viceversa) and this chapter will review several techniques The OL2R movement data that aretypically measured are often quite surprising and there is a great tendency not to believe theresults Each OL2R method has its advantages and disadvantages and it is a good idea tocompare the measurements from two or more methods just to see if the results are similar.There are currently 11 different techniques that have been used to measure this movementthat will be explained in greater detail in this chapter One very popular practice is notrecommended since there are a number of potential problems with it as explained herein

16.4 TAKING ‘‘HOT’’ ALIGNMENT MEASUREMENTS IMMEDIATELY

AFTER SHUTDOWN

One popular, but relatively inaccurate method people have done is to take a quick ‘‘hot’’alignment reading with their shaft alignment measurement system immediately after a unithas been shut down There are some problems doing this however

Safety tagging the machinery to prevent them from inadvertently starting up with ment measurement devices attached to the shafts, removing the coupling guard, mounting theshaft alignment measurement system quickly enough to get a set of readings, and then getting

align-an accurate align-and repeatable set of readings while the shafts are still moving proves to be a realchallenge for the personnel doing the work

This method is not recommended for the following reasons:

1 The machinery is no longer running You cannot assume that the machinery is in exactlythe same position as when it was running Reactionary moments of the rotating elementsand reactionary moments when fluids were flowing through the machine and the

attached piping will not be present with the equipment off-line On small drive systems,

it can take but a few seconds for the shafts to stop turning On larger drive systems with

a lot of rotating momentum, it can take several minutes for the shafts to stop turning.The instant you press the stop button, the equipment begins moving By the time theshafts stop rotating, the equipment is properly safety tagged, the coupling guard isremoved, a shaft alignment system is attached to the shafts, and a complete set ofalignment readings have been taken so that a period of 15 min to 1 h has alreadyelapsed What happened during that time frame?

2 There is a safety related issue here The equipment you will be working around may verywell be physically hot from a temperature standpoint and hot enough to physically harmyou What if somebody forgets to safety tag the machine and it starts backup while youare trying to attach the alignment tooling (or have already attached the tooling)? Youare more apt to make a mistake if you are in a hurry

3 The shafts are probably moving while you are taking the alignment readings If you plan

to attempt this, it is suggested that you take a series of readings, say every 15 to 30 min,during the cooldown period to plot the movement and extrapolate them back to theinstant when the unit was first shut down to determine the actual shaft positions whenrunning The data are usually nonlinear and guessing the slope of the curve during thefirst 15 min to 1 h period after the unit has been shut down is a hit or miss proposition.For the above reasons, this technique is not recommended but if this is all you arewilling to do, then it is better than guessing or doing nothing at all

16.5 FOUR GENERAL CATEGORIES OF OL2R MEASUREMENTS

There are four broad classifications of measurement techniques employed to capture OL2Rmachinery movement:

. Movement of the centerlines of the machine cases with respect to their baseplate or frame. Movement of the centerlines of the machine cases with respect to some remote reference

or observation point

. Movement of one machine case with respect to another machine case

. Movement of one shaft with respect to another shaft

Just as there are advantages and disadvantages of each of the shaft alignment measurementtechniques, there are advantages and disadvantages of each of the OL2R techniques shown inthis chapter After conducting these surveys for many years on a wide variety of equipment,there is always a certain level of uncertainty in the measurement data or in the setup of theequipment Since the results of these surveys can be quite surprising, there is a tendency todisbelieve the first set of measurements So, what do you do?

Often you repeat the test again and see if the results of the second set of measurementssomewhat agree with the results of the first set If there is a wide variation between both sets

of results (e.g., the inboard end of the compressor looked like it moved 62 mils upward thefirst time and 38 mils downward the second time), you need to carefully review every aspect ofthe OL2R equipment setup, the measurement sensors, when and how you collected the data

to determine how this occurred

One of the reasons why several methods are shown in this chapter is to give you theopportunity to compare the results from two or more different techniques It is not uncom-mon to repeat the OL2R survey two or three times getting very similar results each time butthe information you gather may appear to be unbelievable to you and other people So, now