(too old to reply)
Pump coupling question for the boiler guys
Tekkie
2004-12-27 02:29:34 UTC
Jake posted for all of us....
Post by Jake
Post by p***@see_my_sig_for_address.com
Also, if there are any shock absorbers / springs / etc on the
motor or the pump mounts themselves, they need to be right.
Yep... I forgot about that. We had a troubleshoot one time where some plant
maintenance people set a replacement motor in (probably 50 horse or so) and
that thing was chewing up coupling inserts every two or three days. They
just kept changing them and telling the people there "We must got a bad
batch of inserts".
When I got to checking, though, I found OEM shims laying on the ground
nearby. I asked, "Where'd these come from?". When they changed the motor,
they never put the shims back under the feet. Measuring the alignment with a
laser showed about a 1/32 inch side/side misalignment and nearly double that
up/down. Oh, they didn't put the coupling cover back on, either.
Sometimes you've just gotta know what to look for (-;... like parts on the
floor instead of on the machine!
Jake
This leads to my question: How does one tell the alignment is correct? My
recollection is there isn't a lot of room in there when assembled. Then
again WTF do I know.
--
Tekkie
Tekkie
2004-12-27 02:32:35 UTC
posted for all of us....
Post by p***@see_my_sig_for_address.com
http://tinyurl.com/5r82n
Hmmm, calibrated eyeballs
--
Tekkie
BGBevill
2004-12-27 02:32:39 UTC
Post by TURTLE
3) The Back end of the motor is not perfectly alined to the pump shaft but
ever so slite but you can still dial in the alinement but it will be just a hair
off which a lot of millright will let go. This will set up a shifting of the
rubber bushing from 180º and 360º back and forth. It will take 10 to 90 days to
eat the star or Dodger coupling up.
So if they are not pumping welding rods the aliniment is off.
TURTLE
You may be on to something. I made mention while changing the insert that it
looked like to me that the back end of the motor needed to be shifted over a
bit, but I was told all that had been checked. I'll probably get back by there
tomorrow sometime with some tools and take a closer look and get the numbers
off the motor and pump.

thanks,
Bobby
PrecisionMachinisT
2004-12-27 04:05:31 UTC
Post by BGBevill
Post by Jake
I'd be willing to bet that its alignment or run-out, too, but you'd really
need a better description of the type of coupling (those small Falk
couplings are notorious for being very finicky about alignment but not
run-out so much) and how it's failing.
The motor, coupling mating and the pump all need checked by somebody other
than the folks telling you "It's the air". They obviously don't have a
clue...
Jake
The rubber insert in the coupling is a Lovejoy 1L790. The one this
morning was
Post by BGBevill
sheared off just like I would expect should the pump lock up for some
reason.
Post by BGBevill
I am not familiar with this brand coupling at all and as I said earlier,
my
Post by BGBevill
experience is pretty much limited to B&G stuff. The air story got my
attention
Post by BGBevill
because is was a new one on me. Something else that got my attention is
that
Post by BGBevill
there are 3 identical pumps and motors. If air is breaking one, my
question
Post by BGBevill
would be why are the other two doing just fine in the same system? Oh
well,
Post by BGBevill
the air story just ran up a red flag and I figured someone here might have
heard it, if there was anything to it.
Bobby
I like to use the oldham type couplers whenever possible, with a delrin
disc, its very doubtful they would shear even if the pump has completely
locked up.

Dunno if they are in common use for pump shaft coupling, but here is a link:

< http://servovision.com/MM/N147/HUCO/hoco.html >
--
SVL
john
2004-12-27 04:46:54 UTC
Post by Jake
Post by BGBevill
The rubber insert in the coupling is a Lovejoy 1L790. The one this morning was
sheared off just like I would expect should the pump lock up for some reason.
The Lovejoys are very similar to the Falks in design, at least in the flex
EPDM rubber insert series.
What do you mean "sheared off"... like sheared in the middle or one set of
the teeth on the insert?
Post by BGBevill
Something else that got my attention is that
there are 3 identical pumps and motors. If air is breaking one, my question
would be why are the other two doing just fine in the same system? Oh well,
the air story just ran up a red flag and I figured someone here might have
heard it, if there was anything to it.
Bobby
I've never heard of that, and I do commercial motors a lot. The coupling is
not for shear protection, it's there to compensate for minor misalignment
problems, and equipment vibration. If the pump itself was locking up, I'd
guess you'd get a motor overload trip long before you sheared a coupling.
The coupling insert you mentioned is pretty small... 120 inch-pounds
rated... what size motor and what kind of pump is it mated to?
The air story is BS... something else is wrong, IMO...
Jake
If it sheared off the coupling halfs are moving apart because the set
screw is not properly set. IF the setscrew is backing out there is
probaly also a mis alignment of the two shafts. Make sure that there
is only one setscrew in each hole when you tighten them, you can put a
locking set screw on top of the first one but that confuses the average
mechanic. Its common in heavy machinery.

JOhn
Oscar_Lives
2004-12-27 04:52:22 UTC
Post by Jake
Post by p***@see_my_sig_for_address.com
Also, if there are any shock absorbers / springs / etc on the
motor or the pump mounts themselves, they need to be right.
Yep... I forgot about that. We had a troubleshoot one time where some
plant maintenance people set a replacement motor in (probably 50 horse or
so) and that thing was chewing up coupling inserts every two or three
days. They just kept changing them and telling the people there "We must
got a bad batch of inserts".
When I got to checking, though, I found OEM shims laying on the ground
nearby. I asked, "Where'd these come from?". When they changed the motor,
they never put the shims back under the feet. Measuring the alignment with
a laser showed about a 1/32 inch side/side misalignment and nearly double
that up/down. Oh, they didn't put the coupling cover back on, either.
Sometimes you've just gotta know what to look for (-;... like parts on the
floor instead of on the machine!
Jake
I hate to say it, but our union millwrights all get motor/coupler alignment
training on the latest equipment and with the old-fashioned dial-indicator
and calculator methods.

Better call a union millwright for this one.
TURTLE
2004-12-27 06:30:34 UTC
Post by BGBevill
Post by TURTLE
3) The Back end of the motor is not perfectly alined to the pump shaft but
ever so slite but you can still dial in the alinement but it will be just a hair
off which a lot of millright will let go. This will set up a shifting of the
rubber bushing from 180º and 360º back and forth. It will take 10 to 90 days to
eat the star or Dodger coupling up.
So if they are not pumping welding rods the aliniment is off.
TURTLE
You may be on to something. I made mention while changing the insert that it
looked like to me that the back end of the motor needed to be shifted over a
bit, but I was told all that had been checked. I'll probably get back by there
tomorrow sometime with some tools and take a closer look and get the numbers
off the motor and pump.
thanks,
Bobby
This is Turtle.

You don't need any tools to tell a V butt . The motor and the pump makes a V
shaped look to it and offshore they called it a V butt skid. Just look from the
motor end back about 10 feet and you can see it like a road sign that says V
Butt motor here.

Now here comes the Hackish way here of some of the pumper offshore would do.
Loosen up the back two bolts holding it just a little when it can move a little
but not much and just one up front on the motor closest to the pump. Then run
the motor till it comes up to full speed and then cut it off. Sometimes the butt
will come back around and line up pretty close. Then tighten it back up and see
with your mike to see the alinement of it. This will only take care of left to
right and do nothing for up and down alinement. This is really for a motor that
was set perfectly at one time and you pull the pump to clean it out and replace
it. Now if you loosen all 4 bolts of the motor it may leave there and you
watching it leave. Now the best is to reset it and do a perfect job the first
time but use this in a bind and you need the pump running Now and not later.
Now if in dought here. Don't do nothing like this and just aline it right the
hard way with a 16 pound sledge and one eye closed. Do you do your millrighting
yourself or do you call in a Millright?

TURTLE
TURTLE
2004-12-27 06:52:43 UTC
Post by Jake
Post by p***@see_my_sig_for_address.com
Also, if there are any shock absorbers / springs / etc on the
motor or the pump mounts themselves, they need to be right.
Yep... I forgot about that. We had a troubleshoot one time where some plant
maintenance people set a replacement motor in (probably 50 horse or so) and
that thing was chewing up coupling inserts every two or three days. They just
kept changing them and telling the people there "We must got a bad batch of
inserts".
When I got to checking, though, I found OEM shims laying on the ground nearby.
I asked, "Where'd these come from?". When they changed the motor, they never
put the shims back under the feet. Measuring the alignment with a laser showed
about a 1/32 inch side/side misalignment and nearly double that up/down. Oh,
they didn't put the coupling cover back on, either.
Sometimes you've just gotta know what to look for (-;... like parts on the
floor instead of on the machine!
Jake
this is Turtle

I bet you one of them there laser tools would tell you exactly what it was off
at and make some smooth running motors and pumps. With a 32 th side to side and
16 th up and down , they must have used a folding up tape measurer and forgot
their tools at the house.

Them 50 Horses will be wanting to rare up real bad on a 1/16th.

TURTLE
Dr. Hardcrab
2004-12-27 13:49:33 UTC
Post by p***@see_my_sig_for_address.com
Also, if there are any shock absorbers / springs / etc on the
motor or the pump mounts themselves, they need to be right.
I think that model has gas struts.....
Mark Schofield
2004-12-27 18:19:34 UTC
on the B&G package or instruction sheet for the smaller butterfly/spring
metal couplers, it says somewhere that the primary cause of coupling failure
is bad motor mounts. the rubber mounts mentioned in the previous post. or
how about the spot welds holding the motor to the frame which connects to
the bearing assembly.
Post by Bubba
Post by BGBevill
Hello,
This morning when I got to church, we had no heat. When we went to take
a
look, we found a busted pump coupling. There were several spare rubber
couplings there, so we took it aloose, removed the broken rubber and
replaced
it with one of the spares laying there and got it back to running. Upon
going
back down stairs I asked about all the spare pump couplings and was told
that
we are loosing one about every two weeks and the contractor leaves them
for us
to change out in a pinch. I then ask has anyone mentioned what might be
causing us to loose a coupling every two weeks. I was told that our
contractor
said he thought it was air and they were going to install another air vent
to
remove the air and solve the problem. That is my question. I have been
doing
light commercial heating and a/c for close to 20 years and have never
heard of
air causing pump coupling to break. I looked at the alignment and
everything
seemed to be okay. The thing ran without any vibration or anything once
we got
it going. Most of my experience has been with the smaller B&G type
couplings,
although I used to have two accounts that had large Taco pumps with rubber
couplings. Comments anyone?? Anyone had experience with air breaking
pump
couplings?
thanks,
Bobby
Does this motor have rubber motor mounts on each end? If so, change
them.
Bubba
Dr. Hardcrab
2004-12-27 19:14:52 UTC
Post by Mark Schofield
on the B&G package or instruction sheet for the smaller butterfly/spring
metal couplers, it says somewhere that the primary cause of coupling
failure is bad motor mounts. the rubber mounts mentioned in the previous
post. or how about the spot welds holding the motor to the frame which
connects to the bearing assembly.
I am not sure of the brand, just the R.E.Michels number (1W100), but I use
those spring type couplers: brass ends connected by a spring. Never have any
problems with them and have never seen one break (except one where the pump
locked up, and, I guess it's SUPPOSED to break....)
Jake
2004-12-27 21:49:54 UTC
Post by geomanjr
Bobby look at the rear rubber mount on the motor- that is usually where
they wear and start to sag causing a mis-alignment. I have seen this many
times and it will eat couplings like crazy. Just a thought, Mark
I think that's a good idea, Mark. I've seen it a few times, too... on the
rear corner (mostly) that is in line with downward rotation forces.

Jake
Tekkie
2004-12-29 02:55:20 UTC
PrecisionMachinisT posted for all of us....
Post by PrecisionMachinisT
< http://servovision.com/MM/N147/HUCO/hoco.html >
Hmmmm, stiffness index. I think my dick is a negative 3.79
--
Tekkie
PrecisionMachinisT
2004-12-29 03:00:27 UTC
Post by Tekkie
PrecisionMachinisT posted for all of us....
Post by PrecisionMachinisT
< http://servovision.com/MM/N147/HUCO/hoco.html >
Hmmmm, stiffness index. I think my dick is a negative 3.79
Definately some exciting stuff then, eh ???
--
SVL
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