compressor alignment

[Tycho]

Howden WRV 204 (don't remember, might be a 163)

alignment check after 1 year of running.

aligned to within 0.05 mm when cold, howden used to say 0.1 mm, company I work for says max 0.08 mm.

after running the compressor for 1 hour and checking the alignment again, it had moved 0.02 mm on the height, making it 0.06 mm.

http://www.youtube.com/watch?v=bj27sJU5V6Y

balanced a coin on the compressor just for fun

[Brian_UK]

Very smart Tycho.

[hendry]

that's when past experiences are put into practices...
guidelines could not expressedly derive solutions to each problem.

alignment also affected by how other internal parts are properly installed/fixed ...

[RANGER1]

Its a good advertizing for Howden , not that they need it .
It makes you wonder how we survived before lazer alignment .

[NH3LVR]

It makes you wonder how we survived before lazer alignment .

I do not understand the awe people have for laser alignment. (I am thinking of the customers who tell you "Do not move the alignment, it has been LASER ALIGNED).
I do understand that it is easier to learn than tha manual method, however I do not see it is more accurate.
The company I used to work for used the standard of .001 inches (.0254 MM).
But the film is impressive Tycho, good work.

[RANGER1]

Its like car air conditioning , once you have it there is no going back .
It can be more accurate and a lot faster ( all depends who is driving it ) .
I have done a fair share of alignments using double periferal method and can get it to great accuracy , but it takes time .
Lets face it though ,we have a flexible coupling for a reason .
You can nearly do the same with indicators but the beauty is you only have to get it sideways once ,at the end .
Have worked in some plant rooms where indicators flutter with plant vibration , so hard to do good alignment unless plant is off .
It also can give a print out for all to see .
I am only assuming Tyco used lazer .

Unfortunatally younger techs have never had to use indicators so cant appreciate skill in using indicators .

It can also look impressive to a lot of clients , as other companies have to bring in alignment company because they cant do indicators or lazer .
Lazer can measure 1000 th of mm

[RANGER1]

Taka a zero off 1000

[Tycho]

been using laser the last two years, before that it was the mitutoyo clocks.

I believe everybody should learn how to align by using clocks so they understand what they are doing.

But the laser is an awesome tool and I would hate to see the day when someone else is using it and I have to do with the clocks again

I can't see how the laser should be any more accurate than using clocks, the laser can be just as inaccurate, it all depends on the person using it.

[Josip]

Hi, Tycho

been using laser the last two years, before that it was the mitutoyo clocks.

I believe everybody should learn how to align by using clocks so they understand what they are doing.

But the laser is an awesome tool and I would hate to see the day when someone else is using it and I have to do with the clocks again

I can't see how the laser should be any more accurate than using clocks, the laser can be just as inaccurate, it all depends on the person using it.

Definitely.....

if you know what are you doing any tool is ok ... the most important is to have shims of all sizes or adjustable plates...


Always using dials, analog type in the past ... digital one today with big numbers, for easy reading

Best regards, Josip

[RANGER1]

Can i ask what methods you used using dial indicators and what tolerance you worked to ?

[Josip]

Hi, Ranger1

Can i ask what methods you used using dial indicators and what tolerance you worked to ?

I'm using mathematical method .... tolerance depends on manufacturer request and type of coupling ... possible to come down to 0,01mm, but usually is around 0,05mm


Best regards, Josip

[NH3LVR]

Here is a manual for those who are not experienced in shaft alignment, or need a refresher course.

http://www.carlylecompressor.com/Fil...ent_lowres.pdf

[Josip]

Hi all

I was requested from one valuable members of RE Forums to reopen this thread again.

I believe he has a lot of good things to tell us, so here we are.

Other members are also welcome to contribute...

Best regards, Josip

[RANGER1]

Have used dial gauges for years, but used laser for more than 15 years.
To me those who are sceptical of laser have not used one, if they have & don't like it I would say they
probably didn't have the right training.
ON average I would say it's 3 times quicker & twice as accurate.
You can get a print out to give client for records & accuracy..

TO me it's a game to see how close you can get it (challenge).
We make money from alignments & look professional.
YOu include a fee to help pay for it anyway, part of the job, probably tax benefits anyway with depreciation.
A lot of clients would laugh if they saw us using dials as laser is now expected..

[RANGER1]

The Carlisle information is very good, thought I would add some more to it.
I wish I new about it when I was an apprentice!

Our apprentices only know Laser but seem to be OK at it.
I used to carry the dials in case laser had problems, gave that up a long time ago.

The double peripheral method would be the most accurate with dials, you can even
program a scientific calculator to put in readings instead of graph paper.


http://www.alignmentknowledge.com/dialrimface.html
https://www.youtube.com/watch?v=wnQ_2Jm7XTs
http://www.rexnord.com/sites/Process...0Alignment.pdf

http://wea-inc.com/pdf/pump-align.pdf

[NH3LVR]

Nice links RANGER1!
I remember the first one I did with very little coaching and a lot of frustration.
The only thing I have against Laser Alignment is that I never had one at my disposal.
If I need to align something now I borrow a set of dual indicaters from my former employer.
Or else make do with my single setup.
I have two guys here I have taught to do alignment with the single set.
We do not do much of that here though, but they understand it.

Retiring in 86 days!

[RANGER1]

Nice links RANGER1!
I remember the first one I did with very little coaching and a lot of frustration.
The only thing I have against Laser Alignment is that I never had one at my disposal.
If I need to align something now I borrow a set of dual indicaters from my former employer.
Or else make do with my single setup.
I have two guys here I have taught to do alignment with the single set.
We do not do much of that here though, but they understand it.

Retiring in 86 days!

Allthe best in your retirement hope to still hear from you with all your experience.

[Grizzly]

Retiring in 86 days!

Not from the Forum, I hope?
Grizzly

[Glenn Moore]

This brings back a lot of memories of my apprenticeship. During my time training at J&E Hall I used to build a variety of direct coupled chillers. The base frames were pre drilled for the compressor but the motor fixing bolts, we had to drill and tap the holes after doing a pre alignment of the motor to the compressor. This was done using a magnetic base drill . Some of the motor feet had only a small tolerance of the hole to the fixing screw diameter, so you had to be accurate in the drilling and tapping of the motor fixing screw holes to allow for adjustment. Then shimming the motor feet to align the motor coupling to less than a thou.
But the real art was lining up the Duplex machines, where you have 1 motor driving 2 compressors. The base frame had one compressor mount bolts drilled but the motor and the second compressor was drilled and tapped by us. For some reason I enjoyed lining these machines using a dial gauge and slip gauge with feelers and my lead hammer, all of which is still in my tool box gathering dust these days .
Lasers hadn,t been invented back then Oh happy days

[Tycho]

Can i ask what methods you used using dial indicators and what tolerance you worked to ?

First, Thanks Josip


Used dual indicators, one on the rim and one on the face, *edit* I said here that I used the TIR method but it seems to have been a combination of two methods, more info in a later post, sorry *edit*


after a while I made and machined my own rig to make it easier to attach to the kind of couplings we used, and also made a pin to make the coupling halves rotate together. others just used threaded bar that was locked on one half and floating on the other half, but I noticed that the threaded bar has a lot of give in it, and it annoyed me that the indicator pins would slide back and forth as the coupling was rotated.

Max deflection on all angles were 0.08mm, as in, it it was 0.08 then it was not good enough, but I'd accept 0.07mm if I had been struggling long enough

[Tycho]

Have used dial gauges for years, but used laser for more than 15 years.
To me those who are sceptical of laser have not used one, if they have & don't like it I would say they
probably didn't have the right training.
ON average I would say it's 3 times quicker & twice as accurate.
You can get a print out to give client for records & accuracy..

TO me it's a game to see how close you can get it (challenge).
We make money from alignments & look professional.
YOu include a fee to help pay for it anyway, part of the job, probably tax benefits anyway with depreciation.
A lot of clients would laugh if they saw us using dials as laser is now expected..

I have only used a laser the last 5-6 years, I was very skeptical the first time I used it, more on that further down

I feel that having used indicators for so long, I appreciate the good feeling of a near perfect alignment (close to 0.00 as possible) much more than the new guys that have grown up with laser tools that serve you everything on a silver plate on the display.

It's also much faster with a laser, but as I mention above, I feel a bit sad when the new guys aren't impressed by a 0.00 - 0.01 alignment, because I also make it a game to see how close I can get


so back to the story of how I immediately lost all trust in lasers the first time I used one

a father son team of electricians, that I have worked with many times and think very highly of, had done a bearing change on the electro motor for an XRV204.
on this unit the plate heat exchanger was placed so close to the back of the motor that they had to lift the motor and turn it 45 degrees on the frame to get access.

they were packing up when I got there, and we chatted for a while and I saw that they had used a permanent marker on the shims on all 4 corners, jokingly I said "Oh, I see you have marked the position, so I guess I don't have to align it after all" hahaha right
they said they had locked the adjusting screws with locknuts before lifting the motor and only removed them after tightening the foundation bolts, to save me too much trouble.

So I unpacked the laser and set it up, making all the measurements and punching them in to the display, trying not to read too much in the instruction manual as the machinists were watching.

went through the 3-9-12 routine, pressing all the correct buttons, only to get a reading saying that the motor was 0.02mm too high from the center.

*scratches head*

*reads manual* yes I have done everything by the book.

I try again 3 more times and get the same result.

*gets frustrated*

so I went to the car and brought my trusted dial indicators on board, only to get the same result.

I even did it twice to make sure the dials were touching the coupling all the way around

So that's how I went from instant distrust to instant liking of laser alignment tools

-----------------------------------------------------

Another story that just came to mind about lasers happened when I was servicing three XRV204 compressors on a ship in las palmas, and an electrician that was also there asked me if I knew about aligning motors or had any experience with laser alignment tools, because he had been struggling to align the motor of a low pressure hydraulic pump and wondered if I could help.

I said sure and we got to work... First thing I noticed was that his laser was way more advanced than the one we use, and you could get a reading with only 45 degree rotation of the coupling, but there was the option to use 3-9-12, so I set it to that because I was most comfortable with that way.

I spent nearly 2 hours with him, sweating and swearing as the motor seemed to slide out of alignment by us just looking at it.

the coupling was this type:
rubber_coupling.jpg

so I was kind of guessing that the tolerance limits were high enough to be done by eyeball MkI,
but the perfectionist in me and wanting to impress, we soldiered on, in the beginning trying to get it below 0.08mm, but after a while struggling to even get everything under 0.1mm

I must have checked that the measuring heads were secured properly, and that the part of the coupling they were on, were straight and not conical or slanted a hundred times.

A suspicion of a dodgy laser or a very dodgy foundation started filling my mind as I had noticed on a few occasions that the measurements had changed between two readings and the only difference was on which side of the pump I had been standing when doing the readings.

I capitulated and went to get my own laser, hooked it up and got a reading of 0.00 - 0.00 - 0.00

A light bulb started dimly glowing in the back of my mind, so just out of curiosity we set up his laser again, went through all the measurements and came to the screen to start taking readings.

In tiny little text in the bottom right of the screen it said 0/000, so we did an alignment, saved it to the memory card, then found a menu and changed it to 0/00 then did another that we saved to the memory card.

both laughing, we went to his computer and loaded files that would give us the overview of the alignment with all values on and found that we had aligned a 25 year old low pressure hydraulic pump to within 0.0012mm...

[Tycho]

This brings back a lot of memories of my apprenticeship. During my time training at J&E Hall I used to build a variety of direct coupled chillers. The base frames were pre drilled for the compressor but the motor fixing bolts, we had to drill and tap the holes after doing a pre alignment of the motor to the compressor. This was done using a magnetic base drill . Some of the motor feet had only a small tolerance of the hole to the fixing screw diameter, so you had to be accurate in the drilling and tapping of the motor fixing screw holes to allow for adjustment. Then shimming the motor feet to align the motor coupling to less than a thou.
But the real art was lining up the Duplex machines, where you have 1 motor driving 2 compressors. The base frame had one compressor mount bolts drilled but the motor and the second compressor was drilled and tapped by us. For some reason I enjoyed lining these machines using a dial gauge and slip gauge with feelers and my lead hammer, all of which is still in my tool box gathering dust these days .
Lasers hadn,t been invented back then Oh happy days

Always nice to hear stories of the golden days

When I first started in refrigeration, we used Hall monoscrews as well as Howden, I don't know who built the units for us, but back then two of the feet on the motor and the foundation would have conical holes and a tap that fit into the hole that locked the motor in place after the manufacturer had done the alignment, same on the compressor but mostly on only 1 of the feet.

The pins were h... to get out after a few years, but the alignment seemed to keep over time, and didn't even shift when the units were welded to the deck of the ship.

Nowadays, the units are also pre-aligned, but in 100% of the installations we have, we see that the motor has shifted, either during transport, when they put it in the ship, or when the unit is welded to the deck.

It's usually sideways or angular so I'm guessing transport or when they lift it into the ship.

I have thought about those conical pins a few times, but upon inspection I notice that most motor feet are not solid steel any more, just the bare minimum to keep it from cracking when you torque the foundation bolts


When I was new in the game, I was also on a few jobs where we were aligning motors after the compressor had been replaced or had been off the frame for an overhaul, and during the alignment, because the compressor had shifted from it's original position there was the choice between:
1: moving the compressor
2: enlarge the bolt hole in the motor
3: use a lathe and make the diameter of the bolt smaller the place it hits the motor foot

Option 3 was mostly used, I was skeptical the first time we turned 4 M24 bolt down to a diameter of 15mm just below the head, but they held up when we torqued them, and the guy I was with had been doing this thing for a whole year longer than me, so it was ok

Done it myself a few times, but not in the last 15 years

[Tycho]

Retiring in 86 days!

Noooooo!

You still have at least 30 years of work left in you all those refrigerants and other stuff we have been breathing in during our time in the field acts as a preservative, but scrambles our brains, the way it works is that a refrigeration technician never grows old, he only looks that way on the outside, the ability to say "no" when presented with a problem isn't there, and if a refrigeration technician has spare time, he spends it thinking about the last job he was on, if he caught everything... while at the same time already foreseeing the next problem and planning what tools or parts he might need to fix a problem a customer still doesn't know he has

[Tycho]

The Carlisle information is very good, thought I would add some more to it.
I wish I new about it when I was an apprentice!

Our apprentices only know Laser but seem to be OK at it.
I used to carry the dials in case laser had problems, gave that up a long time ago.

The double peripheral method would be the most accurate with dials, you can even
program a scientific calculator to put in readings instead of graph paper.


http://www.alignmentknowledge.com/dialrimface.html
https://www.youtube.com/watch?v=wnQ_2Jm7XTs
http://www.rexnord.com/sites/Process...0Alignment.pdf

http://wea-inc.com/pdf/pump-align.pdf

thanks for the links, some nice information there

However

in this link http://www.rexnord.com/sites/Process...0Alignment.pdf

it says

First, correct the vertical misalignment by shimming under the
equipment
feet.

That is wrong, as wrong as it can get in my book...

1 - Align it sideways
2 - Align the sideways angular
3 - work out the up and down angular with the height

if you do as they say and align the height first, it will be wrong with both dual indicators and a laser, because once you shift the motor sideways it will move the point of reference for the top and bottom of the couplings.

it's always always always sideways first

--------------------------------------------------

Same document, that is a very cumbersome way to find a soft foot, having to have an indicator with a magnetic foot and check each of the motor feets.

Here is an easier way:

1 - Tighten all motor feet to torque, or pounded into place depending on what tool fits.
2 - Position indicator on top of coupling in 12 position.
3 - loosen one bolt, note the reading. Lets say this was back left and the reading was -0.03mm
4 - tighten bolt again and loosen bolt diagonally oposite
5 - so I loosen the front right bolt and the reading is 0.07 mm.
6 - A general acceptance of a soft foot is 0.06mm, however here we have a total difference of 0.1 mm (though both feet are within tolerances).
To rectify this, I would have placed a shim of 0.05 under the front right foot (because we all know that if we shim something the size of the shim is never 100% no matter what they say if you need to lift the motor 0.1mm on all four feet, then you put 0.07 on all feet and everything will be perfect
7 - rinse and repeat on all four feet


I am however glad that they mentioned "thermal growth", something that is, I think, overseen in many cases.
on the units we use, the motor and compressor foundations are welded directly to the oil separator.
this is also part of why I make it a challenge with myself to get as close to zero as I can when I do the cold alignment.

usually the shell of the oil separator will be 35-40C along the bottom (due to the oil heater) when we do the cold alignment, and put to the extreme this means that the oil separator is curved like a banana
making the compressor and motor on top, closer together.

Once we start it up, the oil separator will be uniformly heated and "stretch" into the form it will have in 98% of the running time of the compressor, and it is when the system is at this stage we want the alignment to be within limits.

So when we have done the cold alignment, we leave the coupling cover off and then start the system and run the compressor to max capacity and speed (we use frequency converters on all compressors), and when all temperatures have stabilized, we shut it down and get the laser back on as quickly as possible, because it cools down incredibly fast
and make another alignment check.

I have seen a few times that the warm alignment would be off if the cold alignment was "within 0.07mm", over time I have learned that if you are within 0.03 - 0.04mm the alignment will not go outside of 0.08mm once you have had a warm run

Out of curiosity I have done some alignment checks before a ship went into dry dock, printing the results, then checking it again when the ship is floating and from experience, if the systems are close to midships, and a deck up from the engine room, it will be way out of alignment once the ship is floated again. if it is low down it will be out of alignment in around 60% of the cases.
However if the system is forward or aft of the center of the ship, they seem to keep the alignment.


-----------------------------------
This one: http://wea-inc.com/pdf/pump-align.pdf

was very informative on a basic level, and I have saved it for further use

-----------------------------------

This one: http://www.alignmentknowledge.com/dialrimface.html

Was very informative and is definitely saved for further use
(thanks for giving me material for one of the lessons I have to hold )

However, why does none of the links say that you have to "lock" the two coupling halves together to make sure that you measure the misalignment of the two halves and not dirt or machining faults on the coupling halves?
0.1mm is not that much, if you rotate just the one half of the coupling, a fleck of paint or some rust on the coupling could easily give you a 0.5mm false reading.

------------------------

This link: https://www.youtube.com/watch?v=wnQ_2Jm7XTs

I'm sorry but I didn't make it to the 2 minute mark before I lost interest

-----------------------------------------


My apologies for being such a negative nancy

However, it lead me to find this youtube video.
https://www.youtube.com/watch?v=8A2kpOad4VA
Which I find gives a much better picture of how to work dial indicators

I was familiar with the TIR (which is what I used myself when using dual indicators), I was not aware of the "validity rule" or the "true position sensing", but I have however used the TPS rule without being aware of it.
so I guess you learn something every day

When he said that his vertical alignment was 5 on one side and 25 on the other side, I instantly though he would say that the total deflection, since it's positive on both sides, is highest number minus lowest number and gives 20 and that the coupling should be moved towards the side with the lowest number by half of the result

By "feel" looking at the readings he are getting, I think that motor only needs to be moved sideways before it is aligned

[Tycho]

took a while with the last reply, because I had used too many smily faces... and had to go through the whole post to find and delete some
I use them a lot, because sometimes when I go on a "novel writing spree" it might seem like I am taking a harsh stance against your viewpoints, while in reality I might just be sparking a discussion

and also because the written word even if it is written with a light heart and a smile on your lips might be read in a completely different way by someone who doesn't know the person behind the words

seems like we are the same old gang of misfits in here, so at least you all know that I don't have a single bone of malice in my body


I originally asked Josip to reopen this so I could answer RANGER1's question of

Can i ask what methods you used using dial indicators and what tolerance you worked to ?

I was pleasantly delighted when I saw all the replies as soon as the thread was opened

I think I am done here, unless any one of you want's to start a discussion of "how small it is"

[Tycho]

so as a reply to my reply to RANGER1 in this post, at first I said I used the TIR method when I did alignments.

Turns out I use the validity rule

I set both indicators to 0 at 12 o'clock position, then I take readings at 3 - 6 - 9 on both indicators.

To make it simple, let's use just the rim readings, let's say they are

0

-5 +15


+20


(made up the numbers according to his theory)


so -5 and +15 makes a total difference of 25, and the laws of refrigeration works in alignment as well... - wants to go to + and + wants to go to -

so sideways the total difference is 20 (0.20 mm) and the smallest number always wants to be bigger so divide the total difference by half, and then move the motor towards the side that has the smallest reading

it works the same if you have a reading like this


0

20 40


60

(still following the rule from the video - side + side = top-bottom)

So here we have +20 and +40, the difference is 20, and the motor should be moved towards the lowest number reading, because even if it is not in minus, the lowest number always wants more so the difference divided by half, we end up with this reading:

0

30 30

40


Some of you may just now say that we have disproved the theory of the guy in the video, since the numbers don't add up anymore, but I just took these numbers out of the air, and with the 6 o'clock reading of 40, the side to side numbers should have been in - in my example, since they would be out of center readings (my apologies)

so we have now ended up with side to side readings that are similar, but still outside of an acceptable reading, that means the motor is perfectly aligned to the compressor, but you need to raise or lower it

and if the reading was according to the video it would be like this:


0

-0.30 -0.30

0.60


Meaning that you should remove 0.3mm shims from all four feet of the compressor, to give you a TIR change of 0.6mm on the dial indicator.
And gods be willing if the world was perfect then you would end up with a reading of

0

0 0

0

And the same evening you would also win the lottery, without paying for a ticket, win a free lifetime supply of beer at your local waterhole, win a free paid for vacation for two persons, where you could send your wife to one place and yourself to another place and then you'd snap to and realize that the only person to appreciate this perfect alignment is yourself, and you'd go "He** yeah, whos the man!" and do a fist pump in the air


and last but not least, I like the laser so much more because there is no cheating on the results.


Back then, using dial indicators for alignment when we were asked by the client when we would be done, the closest answer we could give was "we are doing the alignment, it can be anything between 30 minutes and 24 hours, all depending on the compressor motor" back then, none of them had the adjustment screws, so it was all lead hammer and 2X4 or a crowbar trying to shimmy it all into place.

With the laser, combined with the fact that all our compressor units now have adjustment screws, I can say "maximum an hour"

[Tycho]

I see that I am swamping this thread I hope I am spreading some knowledge with all my ranting


Worst alignment I had was on a hall V92 piston compressor with direct drive where the compressor unit was placed abeam (for the nautical challenged, compressor on starboard and motor on port, or sideways in the ship)

I had been overhauling the tops (suction and discharge valves/springs) on the compressor.

This was a compressor on an RSW ship, (they are probably called something else in english, but I cant find it)
For some reason these ships are very high on the bow when the tanks are empty and they are in port. Something that has led us to redesign the heating elements on our compressor units because the element on the port unit (where the heating element would be to the front) isn't touching the oil in the oil separator when the RSW tanks are empty....

Oppsss, sidetracked, so this ship was back at shore, all tanks were empty and the ship was waaay high in the front, almost to the point where I was leaning forward when standing on deck. no adjustment screws, and the compressor kept sliding back into "misalignment" no matter what I did and ended up with using pullies and ropes, but I beat that sucker into submission... using three pullies on the motor of a v92 hall piston may seem like overkill, but I managed it in the end

Another novel by Tycho-

[RANGER1]

Tyco,
You certainly studied the links more than I did, as I was mainly interested in finding double peripheral method.
After looking a bit further & the link you added, it is true you learn something new everyday.
Before the internet how could you possibly find all these methods, probably through word of mouth, luck or never.

The only thing I might disagree with is getting sideways correct first with a laser

The ones we have it can be done last, unless you want to get it close to see if it can be aligned easily without fouling on bolts etc , dials yes totally agree.
We have a lasers, all slightly different. The original with one with clock face plotting 0, 3, 6, 9 & in between point.
The latest one which is Bluetooth (handy on big motors) which when rotated can take hundreds of readings.

In some cases a ruler can be used first to get it within reason so dials or laser can be used
Type of coupling to know what limitations are, but always align better than acceptable if possible
Spacer couplings can have a larger of misalignment but as above.

Have you been in the position with soft foot but not even all around under foot?
Motor foot might be touching on one side but 0.2 mm gap on the other. When you tighten holding down bolt it tries to bend foot/base or basically cause tension/stress, not allowing for good alignment.
You can get laminated shims to correct (very expensive) or cut pieces of shim or in some cases part shims to rectify soft foot.
Carrying out soft foot on compressor can also be good practice so no distortion there (screw or reciprocating).

Side adjustment screws, tighten against motor or back off?
I would lightly do up finger tight, as if thermal growth occurs, who knows.
If you do very tight, then stress on everything.

Spacer coupling measure very accurately so laminated shim packs drive straight (find from manufacturer) when installed, otherwise hub/s have to be moved or corrected on moter/compressor shaft to get correct DBSE (DISTANCE BETWEEN SHAFT ENDS).

With all methods if motor cannot be moved sideways because of bolt binding, then in some cases compressor can be moved to avoid this (especially if it was removed for service & not in same spot).

[Tycho]

Tyco,
You certainly studied the links more than I did, as I was mainly interested in finding double peripheral method.
After looking a bit further & the link you added, it is true you learn something new everyday.
Before the internet how could you possibly find all these methods, probably through word of mouth, luck or never.

The only thing I might disagree with is getting sideways correct first with a laser

The ones we have it can be done last, unless you want to get it close to see if it can be aligned easily without fouling on bolts etc , dials yes totally agree.
We have a lasers, all slightly different. The original with one with clock face plotting 0, 3, 6, 9 & in between point.
The latest one which is Bluetooth (handy on big motors) which when rotated can take hundreds of readings.

In some cases a ruler can be used first to get it within reason so dials or laser can be used
Type of coupling to know what limitations are, but always align better than acceptable if possible
Spacer couplings can have a larger of misalignment but as above.

Have you been in the position with soft foot but not even all around under foot?
Motor foot might be touching on one side but 0.2 mm gap on the other. When you tighten holding down bolt it tries to bend foot/base or basically cause tension/stress, not allowing for good alignment.
You can get laminated shims to correct (very expensive) or cut pieces of shim or in some cases part shims to rectify soft foot.
Carrying out soft foot on compressor can also be good practice so no distortion there (screw or reciprocating).

Side adjustment screws, tighten against motor or back off?
I would lightly do up finger tight, as if thermal growth occurs, who knows.
If you do very tight, then stress on everything.

Spacer coupling measure very accurately so laminated shim packs drive straight (find from manufacturer) when installed, otherwise hub/s have to be moved or corrected on moter/compressor shaft to get correct DBSE (DISTANCE BETWEEN SHAFT ENDS).


With all methods if motor cannot be moved sideways because of bolt binding, then in some cases compressor can be moved to avoid this (especially if it was removed for service & not in same spot).

I have learned to read everything before I dismiss it or agree with it (the hard way) been proven wrong a few times *gasp*


Before the internet, how did we manage to get information?
Learn from the old hands and keep malpractice going

A laser gives you all the changes you need on the screen, it doesn't say you need to do it sideways first, but old habits die hard, so I always do the sideways first to mmake sure me and the laser is on the level when it comes to the height

when the motor is clearly out out of alignment I use a steel ruler to get the couplings within "laser range" +/-1mm


Not sure I understand your point about soft foot, back when I used my indicator, but today, most lasers have a "soft foot" function that guides you through the whole checklist. when mounting the compressor, it's pretty much the same compressor on the same frame, in most cases the compressor has never left the frame.

Not sure about what you mean about soft foot, are you saying that one foot might not have been machined properly? because either way, it would have been picked up if you did a proper check for soft foot on the motor.

even if one foot on the motor was machined wonky, if you did it correctly it should have been picked up..

and if I understand what you are trying to say, that one foot was machined improperly, and that one foot was so wonky that when I tightened the bolt caused my alignment to be outside of 0.08mm, that motor would have been replaced, me, nor the company I worked for would gave accepted "special shims" on a motor foot...

I have to bold out this last bit
Side adjustment screws are just that, side adjustment screw, the alignment reading should be done with the screws slacked off, and they should be locked with a lock nut to keep them from working their way into the motor during operation

[RANGER1]

Tyco,
Would you believe some screw compressor manufacturers do not machine motor & compressor mounting feet!
Alignment then requires all your skills to get it right.
Some feet may even suffered corrosion of feet or very average construction, mounting on plinth, causing twisting.
Some packages are not strong or rigid enough, weather we or someone else made it.
Call it circumstances or cheap construction, but you have to deal with it.

[RANGER1]

http://www.pruftechnik.com/products/.../lamibloc.html
http://reliabilityweb.com/index.php/...ment_shimming/

TYCO & others please look at at second link "unusual circumstances" alignments "step" shimming.
This is life in Australia that I come across regularly.

[Glenn Moore]

Hi Ranger &Tycho
experienced all these problems especially with motor feet being machined uneven and thin undercut feet will very small mount surfaces. But this is where your experience and knowledge kicks in. We used to use sheet tin or steel plate shims, but still great fun when the dial says 0 all round. GREAT STORIES AND INFO Glenn

[Josip]

Hi, all


nice reading and lot learned ...


I never used laser type, but I believe it is very accurate and fast ...

for decades I use simple procedure ...

y=x (b/2a)

Coupling scheme.png


Alignement scheme.png

where

y = thickness of shim under motor feet

b = distance between the fastening bolts on the motor
2a = diameter described by the measuring pin when rotated 180⁰

all in 3 basic steps

1. obtaining parallel shafts on the horizontal plane
2. obtaining parallel displacement for correct centre height
3. obtaining parallel shafts on the vertical plane

Also sometimes fight wit uneven motor feet, sometimes corroded ... or some other funny thing very similar as described within earlier posts ....

but job must be done ...

thanks to all for contribution ...


Best regards, Josip

[Tycho]

Tyco,
Would you believe some screw compressor manufacturers do not machine motor & compressor mounting feet!
Alignment then requires all your skills to get it right.
Some feet may even suffered corrosion of feet or very average construction, mounting on plinth, causing twisting.
Some packages are not strong or rigid enough, weather we or someone else made it.
Call it circumstances or cheap construction, but you have to deal with it.

The worse I have come across is the Gram compressor frame for their screw compressor packages, it's less stable than a mechano kit you would give your kid for christmas.
(I hope they are no longer in production)
We had a specialist on site, he spent a week aligning one unit, and when he was finally done he asked me to verify the results (he used dual indicators).

I knew not to touch the frame while getting the readings, and my readings were way off from his, because he had been leaning on the frame the entire time.

so when he didn't believe my readings, I set the indicator to the 3 o'clock position, zeroed it and told him to watch, then I leaned over the frame the same way he had been doing and the indicator moved 0.4mm and I wasn't a big guy back then

His eyes went like saucer plates, because he had spent his whole life aligning units in the workshop where he could stand on the floor next to it

so every time he moved around the unit he shifted the alignment

[Tycho]

http://www.pruftechnik.com/products/.../lamibloc.html
http://reliabilityweb.com/index.php/...ment_shimming/

TYCO & others please look at at second link "unusual circumstances" alignments "step" shimming.
This is life in Australia that I come across regularly.

I have been lucky enough to not encounter uneven feet on a motor or frame, but I have seen machines where a shim has been cut in half to cover only part of the foot, and I am always careful to put it back in the same place

Also, if you end up with one foot where you have 20 different shims, always consider taking them out and replace them with a thicker shim... so instead of having 10 of 0.1 shims, replace them with a single 1mm shim

[Tycho]

And then there is the guy who doesn't understand why the alignment has moved so much, and after X amount of hours still can't get it within limits, and you are called out and come on site to see that he has forced shims that have been painted over a few times, maybe crumpled them a bit in the effort to get them all back under the motor foot, some of them are old shims cut out from a coke bottle from back when the closes you could get to a 0,01 shim was to cut up a coke can

I try to tell them that "if it's full of paint and looks like ****, it's better to start from scratch"

We use stainless shims for everything now, they might be more expensive in purchase, but it saves a lot of time in doing

[RANGER1]

The worse I have come across is the Gram compressor frame for their screw compressor packages, it's less stable than a mechano kit you would give your kid for christmas.
(I hope they are no longer in production)
We had a specialist on site, he spent a week aligning one unit, and when he was finally done he asked me to verify the results (he used dual indicators).

I knew not to touch the frame while getting the readings, and my readings were way off from his, because he had been leaning on the frame the entire time.

so when he didn't believe my readings, I set the indicator to the 3 o'clock position, zeroed it and told him to watch, then I leaned over the frame the same way he had been doing and the indicator moved 0.4mm and I wasn't a big guy back then

His eyes went like saucer plates, because he had spent his whole life aligning units in the workshop where he could stand on the floor next to it

so every time he moved around the unit he shifted the alignment

Alarm bells would be ringing after day one with that "specialist"
Hope he wasn't paid by the hour!