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Thread: pully alignment

  1. #14
    Join Date
    Aug 2000
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    Austell, Ga.
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    Shame on all Ya'!!!!!

    Not one person mentioned one highly overlooked item...and to overlook this step by using Laser, straight-Edge or String is to have belt(s) up to 1/8" out of alignment!!!!

    The simple fact that the drive pulley or the driven pulley is of a different "Width"!!!

    The much thicker Cast pulleys on a single "A" belt unit using a thin Steel drive pulley & a Cast Driven pulley can...(and does) have a difference in width of up to .224"
    Should this combination be, then by aligning on either the outside or inside will throw you wayyy' out..

    The solution; Simply aling as stated by others....
    THEN!!!
    Check the opposite side to assure "IT" is also in alignement...
    If a difference exists, simply align with equal differences on the thinner pulley...

    Shame on all for not mentioning that Lil' tid-bit...
    Ain't "None" of us as smart as "All" of us..

  2. #15
    Join Date
    Dec 2001
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    Wink

    Originally posted by acddc

    this only works with motor and blower sheaves that have the same thickness wall.

    :-)

  3. #16
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    My most humble apologies...I plumb missed that post...
    Ain't "None" of us as smart as "All" of us..

  4. #17
    Join Date
    Nov 2001
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    east kansas
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    Originally posted by R12rules


    25 guys without a life apart from this, sleep and work

    You mean there is something else than this, sleep, and work?

  5. #18
    Join Date
    Dec 2002
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    davenport, iowa
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    sounds like the string (on both sides of the pulleys) is sufficient enough 'less you wanna spend the extra money for the same end result ???

  6. #19
    Join Date
    Aug 2003
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    S.W. Ontario,Canada
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    Originally posted by fixerup
    Laser alignment kit. A string will work until you can buy the kit.
    What kind of batteries does the string take?

  7. #20
    Join Date
    Mar 2004
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    Austin
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    O.K. So now that we seem to have exhausted the methods for aligning pullies on blowers, let me throw in a little different alignment that has been eating my lunch. But before I ask how you guys, and gals, do it, let me state that I have been successful at getting a good alignment, it just takes me forever to get it and I'm not sure I can explain "how" I get it. How do you align a motor with a pump? The kind of set up where the end of the motor shaft has a lovejoy coupling coupled to the shaft of the pump.

    Maybe I should have started a new post for this question...
    Def. of insanity: doing the same thing over and over again expecting different results!!

  8. #21
    Join Date
    Jan 2003
    Location
    San Jose, Ca
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    I like string, easy to carry up to machine room, easy to get rid of.
    Len
    Old snipes don't die they just loose their steam

  9. #22
    Join Date
    Sep 2004
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    pump to motor alignment, use laser alignment.Before we bought the laser tool we use a dial idicator set up always do angular set up first.

  10. #23
    an "expert" Guest
    Well, I've tried, laser, sting, staight edges, dial indicators and determined the best way ( at least it'll get out of warranty ) is to; loosen motor hold-down bolts and start pump. The motor will align itself and then tighten down motor bolts.
    Just kidding.......... LOL
    The cost and expense to align a pump, so seals won't wear out is an intesting subject. Petro chemical industry use various seals and various costs for certain seals. Some seals require great precision in alignment, others don't.
    Use the eqiupment that will provide the level of tolerance required for the seal. Any Risk Management guy ( person ) will have an interesting point of view on this.

  11. #24
    Join Date
    Nov 2004
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    String is one of my most important layout tools for many straitedge procedures

    [Edited by tin_fab on 12-22-2004 at 11:04 PM]

  12. #25
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    Apr 2003
    Location
    New York
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    Hmm pulley alingnment

    Wew, i must say after reading the experts reply i being a green tech found it spirit killing.for the short ime i been in this field i have grown to like it and yes it kind of make u not want to ask questions.I guess that is the objective of the person that comments in such a way.but u know what ill just keep on asking. "Carma" u will get back what u put out. Okay now how do u use that string again?? LOL.

  13. #26
    Join Date
    Nov 2004
    Location
    Anchorage Alaska / Seattle WA
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    Originally posted by ts ac tech
    O.K. So now that we seem to have exhausted the methods for aligning pullies on blowers, let me throw in a little different alignment that has been eating my lunch. But before I ask how you guys, and gals, do it, let me state that I have been successful at getting a good alignment, it just takes me forever to get it and I'm not sure I can explain "how" I get it. How do you align a motor with a pump? The kind of set up where the end of the motor shaft has a lovejoy coupling coupled to the shaft of the pump.

    Maybe I should have started a new post for this question...
    Well ts pump/motor alignment is the subject for many books and to get a complete answer you probably should get one - get a simple one that deals with principals and not tools. Every one try’s to sell these laser alignment tools. I have used dial indicators - direct reading method - reverse indicating method - lazar alignment tools - string - straight edge - eyeball - self alignment by running. If it is available I have used it. The simplest, least complicated and cheapest method is the direct reading dial indicator method. It’s easy to understand - easy to plot - easy to use. Misalignment is the biggest killer of seals and bearings in pump motors. The smaller motors and pumps do not have much protection associated with them [either electrical or vibration] so when they loose a coupling and it takes out the bearing, odds are the pump will run till the breaker trips when the rotor in the motor wipes out the stator. So instead of needing a coupling now you need everything except a pump body...
    The first this you need to do when faced with an alignment is to get yourself a shim kit. Depending on what size motor you’re dealing with determines which size of shims you need to use. Usually there is one stationary element in your equipment string. It’s usually the pump because of the piping that is used to attach it to the other equipment so it cannot be moved. Because you’re probably not dealing with pumps that are very big odds are they will have relatively small shafts that will be fairly close together. The first thing to do in the alignment is to determine what you are going to align to what. To me the best case is to have a coupling with two identical halves on each shaft. Like Lovejoy. If that is the case, just leave out the spider and you can start the alignment. Mark a spot on each element and take all your readings on these two spots every time. In other words rotate both the pump and the motor around with each set of measurements. I use a magnetic base and a dial indicator. Room plays a big part in which indicators you can use. There are 3 elements to an alignment, horizontal - vertical - and face. Because you are aligning a pump/motor combination the face alignment will not be important. Get a piece of paper and draw circles on it so you can keep up with your "moves." Attach your magnet to the pump and set your indicator on the motor. Align your marks on the top of the elements of the coupling and adjust your dial indicator to "0" - rotate both elements to 90* from TDC in the direction of rotation and take your first reading. Record it on your paper as + or - ?thousands of an inch. Then proceed to take readings at 180* & 270* and then come back to TDC and make sure your indicator comes back to 0. Now you can make an informed decision on how much you have to raise your motor. Generally when you take a motor off you will keep the old shims in relation to their former place to get a general idea on where you will have to go. I always try to get the height in the ball park before I go to the horizontal alignment. Just look at your dial indicator and see how many thousands you are low. Don’t worry about getting it perfect on the first try because as you move the motor from side to side it will affect your relative height also. So within a couple of thousands is fine. When you put the shims in don’t tighten the motor bolts too tight when doing an alignment - you will have to move the motor around some - generally with a hammer. Take another set of readings and see how much lateral movement you will have to make with the motor - I generally put the dial indicator on the side so I can take a direct reading as I tap it over. When you get it where you want it laterally take another set of readings and see where you are. You should be getting fairly close by now. If these two readings are fairly close you need to make sure the faces are parallel. You do this my placing your dial indicator on the face of the other coupling and rotating it around - Do this reading just like the others by rotating both the pump and the motor together - determine how much out it is and raise or lower the back of the motor to get them parallel. Take another set of rim readings and see if you changed things enough to cause another vertical change. If so that should be your last move. Check everything once again and get her tight. There are a few things that determine when you’re finished doing an alignment. First - the specifications of the coupling you are working with. Second the kind of equipment you are working with - third the speed that the equipment is operating at and finally your work ethic. Now Lovejoy couplings are pretty forgiving but on the other hand some of the other couplings with elements that do not like much misalignment will require a better alignment. The higher the speed of the equipment the closer the alignment must be. Just remember this - if you have .010 total run out in an alignment and your machine is rotating at 3600 rpm your coupling will have to absorb 36 inches per min of friction. A normal piece of equipment that is running all the time is generally considered to operate 8000 hours per year - that is equal to 1,440,000 feet per year or 272 miles of wear. So as you can see a few thousands of an inch does add up. With experience you will be able to get things right on pretty quick.. One thing to remember when doing alignments is the offset. If you are working with pumps of equipment that will change temperatures when it comes to operating temperature you will have to figure that into the alignment when you are doing it "cold" - Steel will grow at a rate of .000005 inch per degree. So if your aligning something at 70 degrees that will be pumping 180 degree hot water then you can expect that the pump will grow 180 - 70 x .000005 or .00055 per inch between the base and the shaft. So if your shaft on your pump is 12 inches above the metal base you can say .00055 x 12 or .0066 inches. So in your cold alignment you could align your motor about .007 high and let the pump "grow" into alignment. As you can see a cold alignment could generate several hundred miles of wear in your coupling if you fail to consider the growth of your mechanical elements. You can also see why a nuts on alignment will shake like a dog passing a peach seed if you are pumping a hot medium. Oh yes - as an after thought - don’t be afraid to drill out the bolt holes in a motor if you become "bolt bound" - It happens sometimes.
    I have a good alignment book at home but cannot remember the name of it. If I think if it I will post it for you.
    Hope this helps some.
    John

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