Wobbly Ceiling Fan

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Mark Reardon

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Jun 8, 1992, 1:39:54 PM6/8/92
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In article <10...@stake.DaytonOH.NCR.COM>, bsm...@stake.DaytonOH.NCR.COM (ROBERT SMITH) writes:
|> We recently purchased a house that has a ceiling fan hanging over the front
|> entrance hallway. It is a four paddle fan with a large, multiple light
|> fixture attached to it. The fan hangs down about one foot from the ceiling.
|> The problem is that the fan wobbles excessively. I believe that it must be
|> caused by the blades being somehow out of balance. I noticed that a previous
|> owner had attached lead weights to one of the blades, but obviously this did
|> not help -- it wobbles with or w/o the weights. (BTW, I went in the attic to
|> make sure the fan is securely attached.)
|>
|> I would appreciate any suggestions on how to fix a wobbly ceiling fan.
|> --
|> E-mail => Robert....@daytonoh.ncr.com (Bob Smith)
|> NCR Investor Relations/Stakeholder Relations

First make sure that the motor and blades are level and not close to
an uneven ceiling. If the motor is level and you don't beleive that
an uneven ceiling could be causing the problem, then look at adding
weights to the fan's blades.

They make a kit for doing this that is sold at hardware stores that
sell fans. The first thing I do is try swapping blades to different
positions until the least amount of wobble is seen (all blades do not
have the same weight or weight distribution). Then try placing the
weights on different blades. If it makes the problem worse remove the
weight and try it on another blade or change its location on the blade.

--
Mark

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| Mark Reardon | AT&T Tridom |
| m...@eng.tridom.com | 840 Franklin Court |
| | Marietta, GA 30067 |
---------------------------------------------------------------------

David E. Buxton

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Jun 8, 1992, 2:58:20 PM6/8/92
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What about taking the blades off and running the fan long enough to see
if it wobbles without the blades. That should at least confirm that
it should be possible to balance out the blades. If it wobbles without
the blades then its probably not a balance problem as I'd expect the
fan motor and its short arms to be balanced. But then again, with
todays cheap methods of manufacture you just never know.

DaveB

Kevin Redden - Network Software

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Jun 8, 1992, 4:23:30 PM6/8/92
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I used to think that wobbling ceiling fans were caused by a weight inbalance,
but an old airline captain who have flown 4 engine propeller airliners showed
me the light. He had experience in finding an out of balance propeller years
ago that the mechanics could not find. They had been looking for a weight
inbalance, while the problem was a blade mounting imbalance.

We were building a house for Habitat for Humanity, and the new homeowner had
asked us to hang a used ceiling fan he had bought. When I had it hung and wired,
it swung all over the place, and the airline captian showed me how to tame it.

He explained that the imbalance is almost always a dynamic imbalance caused by
out of alignment blades. He said the manufacturing process kept the blade weight
within an acceptable range, but that the blade fittings end up getting bent
during shipping/installation/use causing the fan to wobble.

At the time I didn't quite beleive him, but since I didn't have a fix, I tried
his method anyway. This was:

1. Hold a ruler against the ceiling at the outside of the blade circle
and make sure the center of the tip of each blade falls at the same point
on the ruler. If any blade is bent up or down and consequently is out of
line, gently bent the center metal blade holder until the blade lines up.

2. With the center of all the blades on the same plain, make sure that
each blade has the same pitch. Measure the top and bottom of the tip of
each blade. They should all be the same. Gently bend the center metal
blade support to change the pitch.

When I had completed this (I found one of the blades badly out of line), the fan
turned very smoothly. it made me a believer.

Kevin Redden

Jonathan E. Quist

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Jun 8, 1992, 4:57:51 PM6/8/92
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In article <1992Jun8.1...@tridom.com> m...@tridom.uucp (Mark Reardon) writes:
>In article <10...@stake.DaytonOH.NCR.COM>, bsm...@stake.DaytonOH.NCR.COM (ROBERT SMITH) writes:
[about wobbly fan]

>First make sure that the motor and blades are level and not close to
>an uneven ceiling. If the motor is level and you don't beleive that
>an uneven ceiling could be causing the problem, then look at adding
>weights to the fan's blades.
>
>They make a kit for doing this that is sold at hardware stores that
>sell fans. The first thing I do is try swapping blades to different
>positions until the least amount of wobble is seen (all blades do not
>have the same weight or weight distribution). Then try placing the

If you want to be a bit more analytical, and assuming the motor itself
is relatively closely balanced, then you can get the blades pretty close
with a quick and dirty homemade balance.

Before any of this, pull the blades off, and try running just the motor,
as another poster suggested. If the motor is badly out of balance,
skip all the below, and follow the instructions on the fan balancing kit.
While you still have one blade on the fan, check for level. If you let
the blade go, and it always rotates to the same spot, then the shaft
is tilted _away_ from that spot. This may or may not be easily
adjustable - it's up to you to decide whether it's level enough.

First, get a coat hanger sturdy enough to support two blades. Add
a couple of wire hooks (easily made from another hanger) with the ends
bent to hook into a common mounting point on the individual blades. Hang
it from a hook and see that it hangs level by itself. (if necessary,
bend the hook on the hanger to adjust the fulcrum point, until it
hangs level.) Add a pair of blade assemblies (the blade _and_ the
mounting bracket, if it's detachable), and hang them to figure out which
is heavier. Compare all the blades until you have the heaviest. This
will be your standard blade. Using the weights from the balancing kit,
add weight to the others to get them to the same weight. (just use
Scotch tape at this point - this is temporary).

Now, the 4 blades all weigh the same - you now need the same center of
gravity on each. Take the standard blade, and balance it on
a pencil, or dowel rod, or best of all the edge of a metal ruler
clamped in place. When you have located the balance point, mark it
and measure it, and mark this same point on the other blades.
Now move the added weights along the length of the blades, until
it balances at the marked point. Mark the location, and again
temporarily fix the weight to the blade. Mount the blades, check
that the weights are in position, and run the fan to check for wobble.
Everything should be pretty close. Once you're satisfied,
permanently mount the balance weights.

And if this is your idea of fun, you could also try balancing any window
fans or oscillating fans you happen to have. (Just make sure any weights
you add are _very_ secure - flying metal isn't fun!) I had to tear down
a window fan a couple years ago (I dropped it down the stairs, and it was,
shall we say, distorted:) so just for fun (Karin was working late) I
balanced the thing. To my surprise, it ran quite a bit quieter.
--
Jonathan E. Quist INTERACTIVE Systems Corporation
j...@i88.isc.com Naperville, IL
'71 CL450-K4 "Gleep" - "Worth the Oppression"
DoD #094 "I'm not mad; just terribly, terribly hurt." HDM #007

gilbert.m.stewart

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Jun 8, 1992, 6:10:49 PM6/8/92
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In article <10...@stake.DaytonOH.NCR.COM>, bsm...@stake.DaytonOH.NCR.COM (ROBERT SMITH) writes:
> We recently purchased a house that has a ceiling fan hanging over the front
> entrance hallway. It is a four paddle fan with a large, multiple light
> fixture attached to it. The fan hangs down about one foot from the ceiling.
> The problem is that the fan wobbles excessively. I believe that it must be
> caused by the blades being somehow out of balance. I noticed that a previous
> owner had attached lead weights to one of the blades, but obviously this did
> not help -- it wobbles with or w/o the weights. (BTW, I went in the attic to
> make sure the fan is securely attached.)

The attachment of the fan is important, but not related to the wobble.

I've installed over thirty ceiling fans and here's what I do. First,
if the wobble is very pronounced, you could have blades that are
damaged or mismatched (one or two blades replaced to "fix" the fan
that the installer thought "looked the same"). You may take them off
and weigh the blades on a balance (I made one out of a yardstick),
two or four at a time. Trim a little off any blades that are heavier
by a significant margin.

Usually, the wobble isn't all that bad. Just annoying. Balancing
kits are available. Usually with adhesive-backed lead. Follow
instructions. I personally just get a large rubber band that will
go around the fan blade, choose one blade at random, wrap the band
around the blade, stick some adhesive tape around the rubber band
and stick it to the back of the blade (that's the top -- I'm a bit
paranoid about tape that might leave marks on the visible side of the
blade -- saves cleanup, if any). Get some thick solder (actually,
any darn stuff that has significant weight/volume will do, but solder
is just convenient. Take a piece a couple inches long and hang it
around the rubber band. See if the wobble decreases or increases.
If it increases, cut the piece smaller. If this decreases the wobble,
you're on the heavy blade. Choose one on the opposite side of the fan.
(If you have a five-blader or three-blader, you might want to experiment
with a pair of adjacent blades, but usually this isn't necessary).
Experiment with different lengths of solder (or other stuff you use
for weights).

It sounds like a bigger pain than it is. Usually only takes a couple
tries. And if you get the general idea, it doesn't matter what you
use for tape or rubber bands or weights. Keep the fan speed slow
until you get most of the wobble out, then raise the speed. Make
sure whatever you use to keep the weight on the fan (hang it nearer
the tape, as centrifugal force will pull the weight, obviously,
farther away from the hub and make your final placement less
accurate) sticks well (I use duct tape -- potentially messy, but
at least it prevents me from killing anyone with this electric
slingshot. Clear packing tape is good, too. In one case, I had
a blade that was markedly heavier than the others (a replacement
case, "Well, it LOOKED the same..."), and I removed material by
drilling holes (discreetly) in the back of the blade bracket and
blade.

GMS

gilbert.m.stewart

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Jun 8, 1992, 6:17:48 PM6/8/92
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I've run into VERY cheap fans whose motors are unbalanced. If it's not
a mechanical (i. e., contact of moving parts against a stationary part,
which would require repair prior to balancing), this can be compensated
for by blade-balancing anyway.

GMS

kal...@skyler.mavd.honeywell.com

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Jun 9, 1992, 11:40:29 AM6/9/92
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My fan had instructions for de-wobbling which noone else has mentioned yet,
so here they are.

First you might verify the motor balance, as indicated by others - run with
no blades. Then install the blades, but tighten the mount screws/bolts only
to a snug degree.

Then try it. If it is smooth, you're done, and VERY LUCKY!. If it does
wobble, next measure the distance between the tips of the blades. Many
fans have enough play in the mounting to make some adjustments. Move them
as necessary to make the tip-to-tip measurements as close as possible. This
should take out most of the wobble. (My five-blade fan is rock-steady at any
speed, and it was my first (and only) fan installation.) If it needs more
work, try the suggestions made by previous contributors.

Good luck.

R. Cage

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Jun 9, 1992, 11:26:28 AM6/9/92
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In article <9...@pivot-sts.sbi.com> kre...@malta.sbi.com (Kevin Redden - Network Software) writes:
[A posting which ought to be required reading for anyone with a
wobbly ceiling fan.]

Folks, Kevin's advice is right on the money, and I speak as one
who has done dynamic balancing professionally as well as written
software for a company which makes balancers.
--
Russ Cage wr...@fmsrl7.srl.ford.com russ%r...@sharkey.cc.umich.edu
* When Ford pays me for my opinions, THEN they can call them theirs. *

_Bad_ cop. No donut.

Bob Rahe

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Jun 10, 1992, 9:05:12 PM6/10/92
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Just one (final?) note: most have given instructions for balancing the
fan, you might just want to check to make sure the pitch of the blades are
the same direction(!) Yup, my father-in-law got one with three blades
pitched one way, and the fourth the opposite. Talk about an imbalance!
Silly, but (from experience) possible. Now HOW that happens is probably
a whole amazing story. 8-)

--

Bob

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Roger Fulton

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Jun 11, 1992, 6:07:21 PM6/11/92
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Speaking of ceiling fans, is it possible to mount
a ceiling fan on my home's cathedral (very slanted)
ceiling? Is there some sort of kit with a wedge
or something in it that makes the fan horizontal?

Thanks in advance.
--
Roger Fulton
ro...@wrq.com

Mark Crimmins

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Jun 11, 1992, 10:17:30 PM6/11/92
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>Speaking of ceiling fans, is it possible to mount
>a ceiling fan on my home's cathedral (very slanted)
>ceiling? Is there some sort of kit with a wedge
>or something in it that makes the fan horizontal?

Yes, they make 'em for this purpose. Just check out shops that
have a lot of fans.

Mark

CCD...@utxvm.cc.utexas.edu

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Jun 12, 1992, 10:32:22 AM6/12/92
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Re: Blades pitched differently. I lived in an apartment with a ceiling
fan whose summer and winter modes were selected by changing the pitch of
the blades rather than changing the direction of rotation of the motor.
You had to push the blade toward the motor and then rotate it on its
linear axis. The blades were spring-loaded and had some sort of pin and
detent to maintain their angle. The first couple of times I had to do
it I had to work some but I got to where I could do it easily.

<@>

gilbert.m.stewart

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Jun 12, 1992, 10:58:26 PM6/12/92
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In article <1992Jun11.2...@u.washington.edu>, ro...@wrq.com (Roger Fulton) writes:
> Speaking of ceiling fans, is it possible to mount
> a ceiling fan on my home's cathedral (very slanted)
> ceiling? Is there some sort of kit with a wedge
> or something in it that makes the fan horizontal?

Many fans come with mounting assemblies consisting of a ball-
and-socket arrangement that allows this. Unless you have a
VERY steep angle, this would work (I think about 45 degrees is okay).
If steeper, a mounting plate from a block of wood trimmed on
a table saw with a hole in the middle would work. Get longer
screws to fasten the fan to the box through the block. Either
way works. I've only needed the latter once, tho', and the drop
tube had to be plenty long to clear the blades from the ceiling.
Would have been better to mount the fan from the peak, but
the owner wanted no more electrical work, so...

GMS

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