Strange Ceiling Fan Hum Problem

Old 06-02-03, 08:49 PM
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Strange Ceiling Fan Hum Problem

I have a problem with the ceiling fans in my home.

We have 5 ceiling fans...all of good quality (not $59 specials)...a couple we've even brought from previous homes.

A few of the fans "hum"'s that same kind of sound you'd get by hooking up an electric motor (i.e...a ceiling fan) to the wrong kind of dimmer when the wrong kind of dimmer switch is turned "down", the motor will hum louder and louder.

But here's the strange part:

The noise gets worse in an orderly fashion as the fans are positioned from one end of the house to the other.

Two fans at one end of the house (as it happens, the farthest from the circuit breaker panel, if that even matters), are humming.

As the fans move "across" the house, the next fan hums a little....the next fan a little more (quite noticeable), and the 5th fam hums a LOT (this is the fan all the way across the house from the completely quiet fans)...all the fans either have no wall switch, or are hooked up to a high quality ceiling fan switch.

I guess I have the fans hooked up to two or three different circuits coming from the circuit breaker panel.

I've suspected some weird phasing problem, or some other problem with the electrical system in the house (built 1987), as opposed to problems with the fans themselves.

I guess I could take, say, the loudest humming fan, and move it all the way across the house and hook it up to see if it still hums, thereby proving that it's not the actual fans themselves but something to do with the wiring that's causing the humming, but, well, I thought I'd ask you guys first <g>.

Thanks for your time.
Old 06-03-03, 07:56 AM
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Are you sure though that the humming is a lack of voltage hum and not from the fan not sitting properly on the ceiling or the box it is mounted too is not secured as good as some of the others?

Can you take a voltage reading at each fan? This way you could find out if the voltage is indeed dropping at the louder humming fans.

If you believe the humming is caused by the voltage you might want to see what else is controlled on each of these circuits and turn off everything except the fan and see if you hear a difference.
Old 06-03-03, 08:41 AM
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Like gard said, the humming may not be electrical related. I don't know whether you've got light kits or not, but that could be the source of the noise. One of my new Hunter fans was making a humming noise at high speed and it turns out it was just a loose bulb. So check your lights kits if you have them. Make sure both the bulbs and shades are tight.
Old 06-03-03, 01:56 PM
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I know what you guys mean by checking to see if some PART of the fan is humming or vibrating...I've checked all the fans, and that does NOT seem to be the case.

I can not easily check the voltages at all the fans (of course because they would have to be disassembled), but I was able to check voltages at wall outlets throughout the house.

I get either 121.5, or 119.5, (give or take a tenth) depending on which wall outlet I check.

I don't know a whole lot about electricity (as far as how voltages are supposed to behave within a house), but I do find it curious that I'm getting these two different voltages, and nothing in between.

But...those voltage differences are basically random...they do NOT decrease in an orderly fashion as I go from one end of the house to the other.

I wouldn't think a whole lot of this humming problem (other than of course being irritated that there is ANY humming), except for the way the humming gets worse and worse as I move across the house...that strikes me being really unusual...I mean, what are the chances that:

1) I randomly installed the 5 fans in perfect order of increasing hum, and

2) That the newest and most expensive fan would be the one that hums the worst!

Anyway, still looking for an answer....

Old 06-03-03, 02:38 PM
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The 121.5 is probably the potential difference from one of you legs to ground, and the 119.5 is the potential difference from the other leg to ground.

I also think the difference in humming is a difference in the individual fans, and not a difference in the voltage. Five fans is a pretty small sample.
Old 06-03-03, 03:21 PM
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Originally posted by John Nelson

I also think the difference in humming is a difference in the individual fans, and not a difference in the voltage. Five fans is a pretty small sample.
I'd agree that the sample is pretty small...but still...5 fans, and in PERFECT ORDER from one side of the house to the other, they go from quiet to some hum, to more hum, to the most hum.

I guess I have to take down two of the fans, swap them, and see if the hums change.

But if they DO change, what does that mean?
Old 06-04-03, 01:53 PM
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5 fan accoustical jam (Tesla revisted?)

I'm by no means an expert in this area, but I will throw my 2 cents worth in. I just installed a $15 Wal-Mart fan in my daughters bedroom (Never again will I buy a fan so cheap). On the two lower speeds it hums like crazy. The interesting thing is that the volume and intensity (and factor of annoyance) changes depending on where you're standing in the room. I've come to the conclusion that it probably has something to do with the accoustics of the room, and the attic, above (roof pitch over various points in the attic above the room, etc...).

You could be experiencing the same problem in your home. The accoustics in the combination of the room the fans are in, and the attic, may cause you to hear different levels of humming as you move throughout the home. I guess you could move a couple of fans, as you plan to, and test this theory.

Post back and let us know how things work out!
Old 06-04-03, 02:16 PM
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The hums remain pretty much constant as I move around the room...maybe I'll get a chance in the next couple days to sway two fans.

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