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Q: Ceiling fan wobble. ( Answered,   0 Comments )
Question  
Subject: Ceiling fan wobble.
Category: Miscellaneous
Asked by: striko-ga
List Price: $50.00
Posted: 22 Jun 2006 19:03 PDT
Expires: 22 Jul 2006 19:03 PDT
Question ID: 740357
How much wobble is acceptable in a ceiling fan?  I recently had one
installe and I am worried that it was not installed properly.
Answer  
Subject: Re: Ceiling fan wobble.
Answered By: tlspiegel-ga on 22 Jun 2006 21:39 PDT
 
Hi striko,

Thank you for your question.  

A newly installed ceiling fan should not wobble or shake.  Either the
installation wasn't done properly, or there is a problem with the fan
motor, the blades, the light kit, or a simple fix such as
re-tightening all screws.

Here are the most common reasons a ceiling fan may wobble and the
solutions to fix the problem.  If you don't feel comfortable trying
any of the suggestions, have your installer check out the following
information in order to fix the wobbling.

=========

Google Groups - Wobbly Ceiling Fan
http://groups.google.com/group/misc.consumers.house/browse_thread/thread/ac115ef5854f816b/6010787a6579e9d2?lnk=st&q=new+ceiling+fan+wobbles+a+little+bit&rnum=4&hl=en#6010787a6579e9d2

"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."

[edit]

"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."

[edit]

"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." 

[edit]

"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."

=========

AbleGroup.net Contractor's Solutions
http://www.ablegroup.net/CeilingFanWobbles.htm

Ceiling Fan Wobbles

"There are several reasons why a ceiling fan wobbles. The blades could
be out of balance, out of track, or warped. The wobble could also
result from air turbulence caused by the blades being closer than 6
inches from one side of a sloped cathedral ceiling or ceiling beam.

You can check to see if the fan blades are out of balance by clipping
a spring-type clothespin to halfway between the tip and the blade iron
on the leading edge of one blade. Turn the fan on to a low speed and
see if the added weight stops the wobble. Try each blade to determine
if it needs more weight. If the clothespin stops the wobble, it should
be replaced with thin, adhesive-backed lead-weighted tape, which
should be available through the fan manufacturer's service center.

Check to see if one or more of the blades are out of track. Using a
yardstick, measure the distance from the ceiling to the tip of each
blade -- it should be equal for each blade. If the distances vary,
contact the nearest manufacturer's service center about correction or
warranty replacement. If the blades are not out of track, try swapping
the blades to correct the problem. Switch the position of two adjacent
blades, while leaving the other two in their original positions. While
the blades are off the fan, lay them on a flat surface to see if they
are warped; if so, replace them."

[See illustration]

=========

http://www.doityourself.com/stry/installceilingfan

"Tip: If the fan wobbles when it runs, its blades may be unbalanced.
To correct this, try interchanging two adjacent blades. If that
doesn't work, take all the blades off and weigh each one on a food or
postal scale. If any is underweight, tape a soft object such as a
pencil eraser or modeling clay to the top center of the blade, making
its weight the same as the others. Fan balancing kits with detailed
instructions are also available. Reinstall the blades and the fan
should run smoothly."

=========

Lamp Depot
http://www.lampdepot.com/service/wobble_problems.htm

Wobble Problems

"Loose Screws:  Any one of about 30 screws on the fan being loose can
cause wobble.  Tighten the following screws: The screws which hold the
blade to the blade iron, the blade iron to the motor. The screws which
secure the downrod to the fan motor. The screws which secure the
downrod to the mounting ball. The screws  which secure the mounting
bracket to the ceiling box. And the screws which attach the ceiling
box to the ceiling.  Sometimes there is play between the screw and the
hole which it screws through, especially where the arm attaches to the
motor.  If the hole is larger than the screw make sure the screw is
tightened in the center of the hole rather than along the edge of the
hole.

Blade Sets:  Each fan you buy has a matched set of blades which are
within 1 gram of each other in weight.  When installing more than one
identical fan into a home care must be taken not to intermix blades
from one fan with blade from another fan.  This is a common problem
when 2 or more identical fans are installed into the same room.  If
this occurs, the fan blades should be removed from the fans, weighed
on a gram scale, and divided into sets by weight and reattached.

Balancing Method 1: Number each of your blades on your fan:  Remove
two of the blades from the motor. Switch the positions of the blades.
Turn on the fan to see if this change reduced the amount of wobble.  
If not put the blades back and switch the positions of two other
blades until a combination of switching reduces the movement.  You
should only balance the fan after making sure all screws are tight as
mentioned above.  It is best to balance the fan in the direction you
tend to use it the most.  Why?  You may be able to balance the fan
perfectly in one direction but when the blade direction is reversed
the fan may still wobble in this opposite direction.

Balancing Method 2: Take a lead weight (or a nickel) and tape it onto
the top side of one of the blades.  Tape it to the middle area of the
blade halfway out from the motor.  Turn the fan on high speed.  If
wobble is the same, or worse, remove the weight and attach it onto
another blade.  Keep trying this until a blade is found which reduces
the amount of movement.  Then remove the weight from the blade which
helped reduce movement and place it towards the end of the blade away
from the motor and turn the fan on high speed.  If this placement
makes it better, you need to possibly add more weight.  If it makes it
worse move the weight closer to the motor.  Once you find a position
which has the greatest effect, permanently glue the weight to the
blade or use double sided tape.

Blade Warping: Remove wood blades from the metal blade iron on all
blades. Stack blades on top of each other and look for gaps.   If the
blades do not lay flat, they are warped.  In some cases a fan may not
wobble with warped blades.  But if after tightening screws and
balancing the blades the fan still wobbles, a new set of blades should
be purchased to replace the warped blades.

Location:  If the fan blades are within several inches of the ceiling
or a wall, wobble can occur due to turbulence of air near the tips of
the blades.  Moving the fan further away from the wall or object may
decrease the amount of movement.

Ceiling Support:  If the fan is attached to a plastic or fiberglass
ceiling box, or if the fan bracket is attached to sheetrock with no
ceiling box, the fan is likely to move.  Proper support for a fan
consists of a metal box screwed to wood directly above the box, or a
UL listed Fan Brace ceiling fan support kit.

Light Kits:  Certain light kits have a certain amount of bounce in
them.  Especially those which extend with arms away from the fan.  The
design of certain light kits can cause them to shake or shudder when
the fan is running causing movement.  This could also be caused by
improper mounting of the light kit.  This in turn can get the fan
moving with the light kit as it shakes.  In some cases you may find
removing your light kit will cause the fan to stop wobbling.  If this
is the case you may want to purchase a different light kit which can
be more tightly secured to the bottom of the fan, and which does not
extend as far away from the center of the fan as your old light."

=========

The Natural Handyman
http://www.naturalhandyman.com/qa/qaceilingfan.shtm

"A wobbly fan is usually (but not always) caused by imbalance in the
blades and/or the blade brackets. Though it would be easy to blame
poor manufacturing and quality control, the fact is that perfect
balance is almost impossible, especially since the unit is assembled
onsite under "human" conditions. Just a slight variation in a blade
caused by "play" in the mounting holes can cause a wobble.
Fortunately, unless the imbalance is substantial, the problem only
appears when the fan runs at higher speeds.

The first thing to determine is if the fan itself has loosened from
its ceiling mount. Try to move the body of the fan? does it appear to
solidly attached? Be careful? if the mount is very loose it could fall
into your hands! The fan will have a cover or plate that will allow
you access to the mounting screws should you need to tighten them.

If the fan seems firmly attached but the mounting box seems to be
moving or sagging? RED FLAG! You fan may have been mounted onto a
non-code electrical box. Nowadays, all ceiling fans must be mounted
onto a special electrical box that is firmly attached across two
ceiling joists with special mounting brackets. In contrast, typical
electrical boxes are only attached to the side of one joist? great for
low weight chandeliers or normal lighting fixtures but not so great
for heavy moving objects! If this appears to be the case, you should
get an electrician to examine the box and if necessary install the
proper supports? or replace the box entirely."

========

Ceiling Fans Information
http://www.faninfo.com/ceiling_fans_balance.html

=========

The Fan Shop.com
http://thefanshop.com/fanfaq/maintenance.htm

=========
Ceiling Fans
http://www.ceiling-fans-ceiling-fans.com/resources/Guides_Fan-Balancing.htm





search strategy -- personal knowledge and keywords:

ceiling fan installation 
mounting balancing
correct shaking
fix wobbling 
shaking blades
fan motor 
light kit

I hope the information provided is helpful to you!

Best regards,
tlspiegel
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