Desk fan problem

|Hi, I have a 3-speed desk fan that is typically on for 8hrs/day. The |controls are four pushbuttons, one for each speed plus Off. | |About a month ago it wouldn't start up on speed one. It would happily start |on speeds 2 and 3 and then switch down to 1. |Now it won't start on speed 2 either. | |When speeds 1 and 2 are selected I can hear the hum of the motor, it just |doesn't start spinning the fan. | |Suggestions please, before speed 3 gives out and I have to poke a stick in |and manually give it a spin to start it!

One drop of oil on each bearing.

Not sure what sort of motor these use, but if the fan still spins freely (no bearing friction), then it may be an induction motor start capacitor which is dying and dropping in value, which should be easy to replace. OTOH, in a week or two's time, you may well find fans all on clearance sales in the stores, making any repair uneconomic.

Lubrication of the spindle/bearing may result in a temporary improvement but basically it's buggered.

My 2c as well. I fly a lot of toy planes on cheap plain bearing motors. After a few hours they always start to dry out and sieze up. 3 in 1 restores.

Apart from that on a mains induction motor, there is only the capacitor to go really..thats generally 5-10 years at least.

The message from snipped-for-privacy@cucumber.demon.co.uk (Andrew Gabriel) contains these words:

Wow! You're going to be rich beyond the dreams of avarice.

Split capacitor induction motor on a desk fan???? Is this a huricane machine???

Me thinks shaded pole induction motor more likely and a small drop of 3 in 1 or sewing machine oil is in order. If it is in an office try shredder oil. DO NOT use wd-40.

Lubrication problem. Oiling it wil help, but wont really solve the problem, as the gunk is all still in there. Use an oil solvent to clean the bearing out then reoil/regrease, then its good to go for another decade or 2. Paraffin, white spirit, turps etc. Also dont overlook the oscillating mechanism, this can be the source of friction sometimes.

NT

Thanks Dave, I will give that a try. Thanks to everyone else who answered as well.

WD40 is also good for cleaning out old oil, but it's not a lubricant, so although it may appear to fix the problem, you should still lubricate the bearing or it will be running dry when the WD40 has evaporated.

The message from snipped-for-privacy@care2.com contains these words:

They often use sintered bearings. A good clean and soak the bearings in light oil (not WD40!) will help for a good long time.

Indeed..but soaking means disassembling the bearings - not usually possible. Just oiling them usually leads to a meniscus of oil around the shaft which eventually gets into the bronze OK.

The message from The Natural Philosopher contains these words:

If you want to disassemble them, give them to an eight year old.

We were somewhere around Barstow, on the edge of the desert, when the drugs began to take hold. I remember "PM" saying something like:

Mine does exactly the same every so often. It's crap gumming up the motor spindle and the starting torque isn't enough to overcome it. All I do is give the spindle a spray of penetrating oil to wash it out a bit then a drop of motor oil once a year - something like 3in1 does it fine.

wd40 makes a very poor lubricant, and would be inadeqaute for the lube part of a job like this. It may work to clear things up a bit, but oil is needed afterwards.

NT

I beg to differ! It's a kind of penetrating oil with a variety of uses. When the solvent evaporates it leaves a thin film of oil behind. I quote from the WD-40 aerosol can:

Stops squeaks (sub-heading). "Penetrates and lubricates hinges. castors, springs, taps, handles, windows, pedals, and office chairs".

Frees sticky mechanisms (sub-heading). "Un-jams and lubricates door locks, zippers, sewing machines, typewriter keys, controls, linkages and cables.

Sylvain.

I use WD-40 in the first instance if armature does not rotate freely; then I use the usual lubricating oil.

Sylvain.

As is generally agreed, WD-40 is a good _penetrating_ oil. Although it will work on its own (fan motor spindle/bushes seize up, but don't appear to wear much (if at all), I agree that the use of a general purpose lubricating oil (bicycle oil, sewing machine oil, 2-stroke oil, etc...) is advisable.

I find that fan motors with generous rotor end-float don't seize up. I believe that this is a design feature, and not a fault.

Sylvain.

without unplugging first.

Well it doesn't lubricate properly. Its actually a Water Dispersant first and foremost.