PDA

View Full Version : Re: does anybody know how to balance a ceiling fan?


Patricia
June 30th 03, 03:34 PM
> From: FACE >
> Newsgroups: misc.consumers.frugal-living
> Date: Mon, 30 Jun 2003 09:05:29 -0400
> Subject: Re: does anybody know how to balance a ceiling fan?

> Yes. Good thought there. Will check again.
> From a previous post I now wonder if I did not change the pitch and lift when
> cleaning them with a rag.
---------------------------->

Our bedroom fan wobbled....

Since It needed to be cleaned anyway (white) I got out the tall ladder.

While cleaning....I noticed two of the screws that secure the blades had
backed off a bit and seemed loose....I tightened the two and checked the
others.

No more wobble....

Good luck..
Patricia

Patricia
June 30th 03, 03:34 PM
> From: FACE >
> Newsgroups: misc.consumers.frugal-living
> Date: Mon, 30 Jun 2003 09:05:29 -0400
> Subject: Re: does anybody know how to balance a ceiling fan?

> Yes. Good thought there. Will check again.
> From a previous post I now wonder if I did not change the pitch and lift when
> cleaning them with a rag.
---------------------------->

Our bedroom fan wobbled....

Since It needed to be cleaned anyway (white) I got out the tall ladder.

While cleaning....I noticed two of the screws that secure the blades had
backed off a bit and seemed loose....I tightened the two and checked the
others.

No more wobble....

Good luck..
Patricia

Don K
July 1st 03, 02:40 AM
> wrote in message
...
> "Don K" > wrote:
> >Suppose the two blades weigh the same, but the weight is
> >distributed differently so that one has more weight at its far end?
> >
> >Wouldn't the centripetal force be greater on one side and
> >cause it to wobble?
> >
> >Don
>
> Yep. Since the blades are supposedly equal in length, the blade that has
the
> greatest off-center mass will have the greatest excursion, slowly moving a
> colored felt tip marker into the end of the rotating blades will mark that
> blade. Weights would then go on the blade(s) opposite.

On the face of it, this seems like a good idea, but I'm sitting here,
waving my hand in a tight circle, trying to visualize the movement.

I'm thinking that the excursion might lag behind the actual position
of the heavy blade for two reasons:

First the hanging fan may have a mechanical resonance that may
be some sub-multiple of the spinning frequency. In 2 dimensions,
this would be analogous to someone pushing a swing. You can
"push" several times during a swing, but the one that counts is
the one that catches the swing at its peak excursion.

Secondly, I'm thinking that the movement of the fan is either
a circle or some unstable elliptical pattern. In either case,
I think the wobble movement will be trailing behind the
spinning blade because of the fan's inertia.

Anyway, my kids are now starting to look at me strangely as I
alternate between spinning my hand in a circle and type on
the computer, so that's all I have to say.

Don

Don K
July 1st 03, 02:40 AM
> wrote in message
...
> "Don K" > wrote:
> >Suppose the two blades weigh the same, but the weight is
> >distributed differently so that one has more weight at its far end?
> >
> >Wouldn't the centripetal force be greater on one side and
> >cause it to wobble?
> >
> >Don
>
> Yep. Since the blades are supposedly equal in length, the blade that has
the
> greatest off-center mass will have the greatest excursion, slowly moving a
> colored felt tip marker into the end of the rotating blades will mark that
> blade. Weights would then go on the blade(s) opposite.

On the face of it, this seems like a good idea, but I'm sitting here,
waving my hand in a tight circle, trying to visualize the movement.

I'm thinking that the excursion might lag behind the actual position
of the heavy blade for two reasons:

First the hanging fan may have a mechanical resonance that may
be some sub-multiple of the spinning frequency. In 2 dimensions,
this would be analogous to someone pushing a swing. You can
"push" several times during a swing, but the one that counts is
the one that catches the swing at its peak excursion.

Secondly, I'm thinking that the movement of the fan is either
a circle or some unstable elliptical pattern. In either case,
I think the wobble movement will be trailing behind the
spinning blade because of the fan's inertia.

Anyway, my kids are now starting to look at me strangely as I
alternate between spinning my hand in a circle and type on
the computer, so that's all I have to say.

Don

JazzMan
July 1st 03, 03:19 AM
Don K wrote:
>
> > wrote in message
> ...
> > "Don K" > wrote:
> > >Suppose the two blades weigh the same, but the weight is
> > >distributed differently so that one has more weight at its far end?
> > >
> > >Wouldn't the centripetal force be greater on one side and
> > >cause it to wobble?
> > >
> > >Don
> >
> > Yep. Since the blades are supposedly equal in length, the blade that has
> the
> > greatest off-center mass will have the greatest excursion, slowly moving a
> > colored felt tip marker into the end of the rotating blades will mark that
> > blade. Weights would then go on the blade(s) opposite.
>
> On the face of it, this seems like a good idea, but I'm sitting here,
> waving my hand in a tight circle, trying to visualize the movement.
>
> I'm thinking that the excursion might lag behind the actual position
> of the heavy blade for two reasons:
>
> First the hanging fan may have a mechanical resonance that may
> be some sub-multiple of the spinning frequency. In 2 dimensions,
> this would be analogous to someone pushing a swing. You can
> "push" several times during a swing, but the one that counts is
> the one that catches the swing at its peak excursion.
>
> Secondly, I'm thinking that the movement of the fan is either
> a circle or some unstable elliptical pattern. In either case,
> I think the wobble movement will be trailing behind the
> spinning blade because of the fan's inertia.
>
> Anyway, my kids are now starting to look at me strangely as I
> alternate between spinning my hand in a circle and type on
> the computer, so that's all I have to say.
>
> Don


You'll have precession, but the more interesting thing
will be watching the marker be whacked out of the hand
of the person holding it, whereupon it will leave nasty
permanent stains on the wall and carpet as it falls and
bounces around. Hopefully the person won't get any
broken bones.

JazzMan
--
***************************************
Please reply to jsavage"at"airmail.net.
Curse those darned bulk e-mailers!
***************************************

JazzMan
July 1st 03, 03:19 AM
Don K wrote:
>
> > wrote in message
> ...
> > "Don K" > wrote:
> > >Suppose the two blades weigh the same, but the weight is
> > >distributed differently so that one has more weight at its far end?
> > >
> > >Wouldn't the centripetal force be greater on one side and
> > >cause it to wobble?
> > >
> > >Don
> >
> > Yep. Since the blades are supposedly equal in length, the blade that has
> the
> > greatest off-center mass will have the greatest excursion, slowly moving a
> > colored felt tip marker into the end of the rotating blades will mark that
> > blade. Weights would then go on the blade(s) opposite.
>
> On the face of it, this seems like a good idea, but I'm sitting here,
> waving my hand in a tight circle, trying to visualize the movement.
>
> I'm thinking that the excursion might lag behind the actual position
> of the heavy blade for two reasons:
>
> First the hanging fan may have a mechanical resonance that may
> be some sub-multiple of the spinning frequency. In 2 dimensions,
> this would be analogous to someone pushing a swing. You can
> "push" several times during a swing, but the one that counts is
> the one that catches the swing at its peak excursion.
>
> Secondly, I'm thinking that the movement of the fan is either
> a circle or some unstable elliptical pattern. In either case,
> I think the wobble movement will be trailing behind the
> spinning blade because of the fan's inertia.
>
> Anyway, my kids are now starting to look at me strangely as I
> alternate between spinning my hand in a circle and type on
> the computer, so that's all I have to say.
>
> Don


You'll have precession, but the more interesting thing
will be watching the marker be whacked out of the hand
of the person holding it, whereupon it will leave nasty
permanent stains on the wall and carpet as it falls and
bounces around. Hopefully the person won't get any
broken bones.

JazzMan
--
***************************************
Please reply to jsavage"at"airmail.net.
Curse those darned bulk e-mailers!
***************************************

Bob Mounger
July 1st 03, 05:48 PM
Patricia wrote:
>
> > From: FACE >
> > Newsgroups: misc.consumers.frugal-living
> > Date: Mon, 30 Jun 2003 09:05:29 -0400
> > Subject: Re: does anybody know how to balance a ceiling fan?
>
> > Yes. Good thought there. Will check again.
> > From a previous post I now wonder if I did not change the pitch and lift when
> > cleaning them with a rag.
> ---------------------------->
>
> Our bedroom fan wobbled....
>
> Since It needed to be cleaned anyway (white) I got out the tall ladder.
>
> While cleaning....I noticed two of the screws that secure the blades had
> backed off a bit and seemed loose....I tightened the two and checked the
> others.
>
> No more wobble....
>
> Good luck..
> Patricia


If the blades are old or in a bedroom close to a bathroom where
people shower there may be substantial warping. When ours was wobbling
badly,
I replaced the blades and could run it full speed with no noise.


--
Bob Mounger

Bob Mounger
July 1st 03, 05:48 PM
Patricia wrote:
>
> > From: FACE >
> > Newsgroups: misc.consumers.frugal-living
> > Date: Mon, 30 Jun 2003 09:05:29 -0400
> > Subject: Re: does anybody know how to balance a ceiling fan?
>
> > Yes. Good thought there. Will check again.
> > From a previous post I now wonder if I did not change the pitch and lift when
> > cleaning them with a rag.
> ---------------------------->
>
> Our bedroom fan wobbled....
>
> Since It needed to be cleaned anyway (white) I got out the tall ladder.
>
> While cleaning....I noticed two of the screws that secure the blades had
> backed off a bit and seemed loose....I tightened the two and checked the
> others.
>
> No more wobble....
>
> Good luck..
> Patricia


If the blades are old or in a bedroom close to a bathroom where
people shower there may be substantial warping. When ours was wobbling
badly,
I replaced the blades and could run it full speed with no noise.


--
Bob Mounger

Google