Singing Fan

I have a small window fan in my workshop. It's one of those old metal expandable units that fits any width of window by moving the sides. The fan blade is only about 9 or 10 inches. The motor is a shaded pole motor, similar to the motors used in the old record turntables. But this fan sings. It stays at a constant speed, but the tone varies. It can be heard 300 feet away. It's not a grinding sound and the blade is not rubbing the housing. It's just purrs along, while changing in pitch. Sometimes it's pretty constant, then suddenly the sound will go up and down rapidly for a half minute or so. At first it was sort of annoying, but after awhile I have grown to like the sound. Its sort of soothing and varies like the waves on a lake.
However, just because it's a perfect fit for the small window in that shed, I decided to take it apart and make sure it was oiled. The bearings are all pretty tight. I oiled it's bearings well and reassembled it. I was surprised that it was much quieter for the first ten minutes. Then it went back to singing.
Just curious if anyone knows why it makes these sounds?
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
It's probably got some roughness, in the bearings. What kind of oil did you use? Should use ND-20. After complete cleaning, of course. Need to flush out the old oil with solvent.
Christopher A. Young Learn more about Jesus www.lds.org .
I have a small window fan in my workshop. It's one of those old metal expandable units that fits any width of window by moving the sides. The fan blade is only about 9 or 10 inches. The motor is a shaded pole motor, similar to the motors used in the old record turntables. But this fan sings. It stays at a constant speed, but the tone varies. It can be heard 300 feet away. It's not a grinding sound and the blade is not rubbing the housing. It's just purrs along, while changing in pitch. Sometimes it's pretty constant, then suddenly the sound will go up and down rapidly for a half minute or so. At first it was sort of annoying, but after awhile I have grown to like the sound. Its sort of soothing and varies like the waves on a lake.
However, just because it's a perfect fit for the small window in that shed, I decided to take it apart and make sure it was oiled. The bearings are all pretty tight. I oiled it's bearings well and reassembled it. I was surprised that it was much quieter for the first ten minutes. Then it went back to singing.
Just curious if anyone knows why it makes these sounds?
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
When a motor hums, it doesn't know the words.
What song does your fan sing?
Christopher A. Young Learn more about Jesus www.lds.org .
I have a small window fan in my workshop. It's one of those old metal expandable units that fits any width of window by moving the sides. The fan blade is only about 9 or 10 inches. The motor is a shaded pole motor, similar to the motors used in the old record turntables. But this fan sings. It stays at a constant speed, but the tone varies. It can be heard 300 feet away. It's not a grinding sound and the blade is not rubbing the housing. It's just purrs along, while changing in pitch. Sometimes it's pretty constant, then suddenly the sound will go up and down rapidly for a half minute or so. At first it was sort of annoying, but after awhile I have grown to like the sound. Its sort of soothing and varies like the waves on a lake.
However, just because it's a perfect fit for the small window in that shed, I decided to take it apart and make sure it was oiled. The bearings are all pretty tight. I oiled it's bearings well and reassembled it. I was surprised that it was much quieter for the first ten minutes. Then it went back to singing.
Just curious if anyone knows why it makes these sounds?
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
On 7/3/2012 6:58 AM, snipped-for-privacy@thecave.com wrote:

Does it have a run capacitor, I've seen situations where a defective run capacitor will make an AC motor make an odd sound. ^_^
TDD
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
snipped-for-privacy@thecave.com wrote:

Could the pitch be changing because of varying wind pressure against the window the fan is mounted in.
(I just love that nowadays I can end a sentence with a preposition and nobody cares that I do.)
Jeff
--
Jeffry Wisnia
(W1BSV + Brass Rat '57 EE)
  Click to see the full signature.
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
On Tue, 03 Jul 2012 12:18:41 -0400, jeff_wisnia

That was actually my first thoughts. However, we have had days of calm wind free weather. It does not seem to indicate that the wind (or lack of it) has any effect. For the heck of it, I placed another fan on the work bench in there and blew that fan toward the noisy one. There was little noticable change. However, I found that there is a certain amound of back and forth play in the motor. What I mean, is that the fan blade can be moved forward (away from the motor, or backward (toward it). This play is very small, but it exists. What causes this is beyond me, but I suspect that there may have been a fiber washer in there when it was new, and that wore out. This play is not visible when it's spinning, but I suspect that the in and out movement of the shaft is causing the different pitch. Putting a shim in it might be possible. I'll have to check what is available. Yet it seems to me that this type of motor always had a little play. After all, if they are too tight, they would drag and overheat. After all, this is a fractional HP motor. My guess would be 1/20 HP at most. No, there are no capacitors. Like I said, this is about the same as the old record player motors. Basically a laminated iron housing with coils and the rotating magnets in the middle connected to the shaft. (similar to this).
http://www.cprmotor.com/products_img/Shaded_pole_motor_yj58.jpg
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
On Jul 4, 3:28am, snipped-for-privacy@thecave.com wrote:

try more oil first, then chek to see if bearings are slipping in their housing
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
On Jul 4, 4:28am, snipped-for-privacy@thecave.com wrote:

Ignore the play in the shaft.
All fans will have back and forth movement of the blade. I just checked 4 different fans:
A floor standing model, 2 dual blade window fans from different manufacturers and an rather old "industrial" style fan from back in the 60's.
Something like this:
http://i68.photobucket.com/albums/i18/Byberrianfanman/Fans/fansstuff6861.jpg Each and every one of them has a small amount of back and forth movement of the shaft.
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
On Jul 3, 6:58am, snipped-for-privacy@thecave.com wrote:

Maybe the bearings still does not have enough oil. Also, the bearings are mounted in spring-finger type of arrangement in many motors, if the bearings are too tight, the entire bearing may be rotating in the spring-finger mounts.
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
On Tuesday, July 3, 2012 4:58:52 AM UTC-7, (unknown) wrote:

You need to get one of these to accompany it:
http://www.hayneedle.com/sale/woodstockcelticwindchime.cfm?source=googleshop&mr:trackingCode C53471-6177-E111-A36F-001B21BCC0BC&mr:referralID=NA
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload

HomeOwnersHub.com is a website for homeowners and building and maintenance pros. It is not affiliated with any of the manufacturers or service providers discussed here. All logos and trade names are the property of their respective owners.