Table fan repair

[PE]

I have an oscillating table fan that recently stopped working. I'll probably just buy an new one, but wondered if anyone here might have any useful suggestions. The fan's performance didn't degrade over time; it was working properly and then suddenly it just wouldn't turn on. I've tested the 4 way switch (Off-1-2-3) and it's working properly. And when the control is switched to any of of the "on" settings, the motor doesn't even make a humming sound and rotation can't be started by giving the fan blades a shove, so I assume the problem is not with the motor starting capacitor. The shaft can be turned freely by hand and there don't seem to be any broken or disconnected wires. Are there any other "usual causes" of this type problem that should be investigated before I throw this thing away? Thanks for your replies!

[PE]

I have an oscillating table fan that recently stopped working. I'll probably just buy an new one, but wondered if anyone here might have any useful suggestions. The fan's performance didn't degrade over time; it was working properly and then suddenly it just wouldn't turn on. I've tested the 4 way switch (Off-1-2-3) and it's working properly. And when the control is switched to any of of the "on" settings, the motor doesn't even make a humming sound and rotation can't be started by giving the fan blades a shove, so I assume the problem is not with the motor starting capacitor. The shaft can be turned freely by hand and there don't seem to be any broken or disconnected wires. Are there any other "usual causes" of this type problem that should be investigated before I throw this thing away? Thanks for your replies!

[Oren]

Bad wall outlet/receptacle?

Try the fan in another room and see if it works for you.

[John Grabowski]

*Check the cord close to where it enters the fan and also at the plug end. Sometimes the wire inside the cord eventually breaks from too much swaying.

[mm]

Is the plug good? In general, when you turn the fan on and connect an ohmmeter across the plug prongs (take it out of the wall first), do you get non-infinite resistance?

[Tegger]

"PE" wrote in news:i4s5b7$2t5$ [e-mail]:

Is the motor always live with the switch providing ground (short to ground), or is the motor always dead until the switch provides voltage (short to voltage)?

Either way, check for the presences of voltage and ground in the appropriate places.

Sometimes there are thermal fuses in the motor. Check for those as well.

[PE]

[BQ340]

Also test the wire that runs from the stand to the motor, it flexes as the fan oscillates.

MikeB

[Jeff Thies]

Actually fans almost never have motor start capacitors, they have a "shaded" winding to give them a kick in the right direction. The starting torque required needs little more than that.

Get out your ohm meter and set it on ohms and walk back the path from both sides of the plug. Wires frequently break just after strain reliefs or grommets. You can push a needle through the wire if you need a convenient place to test.

Tegger's suggestion is a good possibility also.

Fans aren't made the way they used to. I've been tossing all my home fans except the Lasko, which is a good product.

Jeff

[mm]

This is sort of related. I have an old 8 or 10 inch fan, -- to judge its age, almost everything that shows is plastic -- and I use a remote switch on a cord to turn it on and off, and a light dimmer to have it run a little slower than speed 2 iirc. (at full speed 2, the noise bothers me) When I had tried setting the dimmer below the current setting, it wouldn't run at all, but it's been running at this setting almost every day for hours all summer for 5 or more years.

Early this year, after I turned it, on it would run a quarter turn, then slow to a stop, and could take up to a half hour before it got moving again, first slowly and within a couple minutes the normal speed.

This went on for 2 or 3 months, even on cool days, but about a week ago, it stopped and now it turns on correctly right away. Like it used to.

LIfe is so strange.

[Jeff Thies]

AFAIK, fans aren't supposed to run on ordinary light dimmers. They are designed to run at some slippage (more slippage, more torque) off the synchronous speed. You are sort of fooling with the slippage needed to generate enough torque to run the fan by reducing the "power" in. I'm rather amazed it "works", but what do I know!

There are special motor speed controllers, not that I know how they work, but you may wish to try one.

Never hurts to work a little oil into the bearings (probably SAE 20 or 30 non detergent), perhaps it got a little gunked up and worked itself free.

Then again, why argue with 5 years of working?

Just my take on it.

Jeff

[mm]

Yeah every time I bring this up, someone, or more, here brings that up

-- you're more tactful than most :) --, but I've been doing this with several different fans for more than 20 years. Of the 6 or 8 fans I've tried this with, only one of them wouldn't work, and for that one I eventually got a fan speed controller, like would be in the wall for a ceiling fan, and put that in a little box to control the table fan. I have fans in 3, sometimes 4 rooms that I run this way.

They were harder to find, came unassembled for my purpose, maybe were much more expensive than light dimmers, and had to be disassembled from the wall plate they were always mounted to. OTOH the lamp dimmer was all set up for me with a pretty little box and a slide control, a cord with an end that both plugged into the wall and the lamp/fan was plugged into it. The little box was meant to be put on a table near one's chair.

After about 10 years I came across the fan control all by itself for a surplus price. By this time I had the other 2 or 3 rooms set up and running, but I made up one for fans that required it.

Maybe, but the plastic is getting brittle too and I'd rather not touch it, let alone take the case apart. :)

I appreciate it.

[Tony]

Did you check continuity from one plug prong to the other... should show little resistance... but only when the switch is on HIGH.

[Bob Villa]

I understand your meaning here...but my vernacular would be different. As in "common to neutral" and "common to hot"

[Stormin Mormon]

Since you have VOM, you could check for continutity between the two plug terminals. Switch to off, (should be infinite) and then the three settings (near zero ohms). That would give you at least some more information.

I've seen some table fans with small run capacitor, on the top of the motor, in the back.

[Stormin Mormon]

Didn't see that, when I wrote the last post.

Please check continuity from prong to prong. If that's good (near zero ohms) then I'd think either run cap, or motor windings. More likely run cap.

[mm]

I read this but didn't really get it before. Tony's right. To the on/off switch isn't what I meant. It's not the same as "across the plug prongs". "From one prong to the other" is clearer. Doing that checks the entire circuit, not just the plug and the cord.