Fan Motor Bearing

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tornitore45
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Fan Motor Bearing

Post by tornitore45 » Fri Sep 27, 2013 4:05 pm

You could buy, today, a 1940 vintage, table fan with metal blades, those that can easily chop a finger trough a minimal protecting cage.
It will be considered an antique and cost more that a Wall-Mart special but you can change the crumbling cord and it will run as new, probably for anoter 5 decades.

You could buy the best quality?? (most expensive??) modern fan and infallibly in much less that 5 year the bearing oil will cook to something similar to Locktite.

On the surface the bearings look the same, the modern fan has an Oilite self aligning bearing (they were more accurate in the old days); the old fan has what look like a bronze sleeve and a oil hole or a wick or even an oil cup.

I have tried to resoak the wick that feed the Oilite bearing but once the motor is hard to turn and the shaft feels gummy the restored life is minimal.
What is the secret to have a fan motor bearing run for decades with no more than a drop of oil when it start squealing?
Last edited by tornitore45 on Fri Sep 27, 2013 6:28 pm, edited 1 time in total.
Mauro Gaetano
in Austin TX

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warmstrong1955
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Re: Fan Motor Bearing

Post by warmstrong1955 » Fri Sep 27, 2013 4:36 pm

I resurrected one of those old fans several years ago. Had a guard on it that would maybe....just maybe keep out an orange. Maybe it would work for those 'ham-handed' fellas that Harold is so fond of. The thing would hardly turn by hand, much less on it's own.
Whatever oil had been used, looked more like shellac. I cleaned up the original bearings, and the motor shaft, polished things up a bit, and replaced the wicks with some new felt I had leftover from fixing a couple chain oilers. Back to the geology department it went.... like new...one owner.

:)
Bill
Today's solutions are tomorrow's problems.

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ctwo
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Re: Fan Motor Bearing

Post by ctwo » Fri Sep 27, 2013 5:07 pm

I liked your post so much that I immediately went on craigslist looking for a vintage fan and, you're right! I found a regular size vintage table fan, and the comment about loosing fingers was included... a hundred bucks and two hour drive! Maybe in my dreams...

This would be so cool...

http://sfbay.craigslist.org/sby/atq/4085585553.html
Standards are so important that everyone must have their own...
To measure is to know - Lord Kelvin
Disclaimer: I'm just a guy with a few machines...

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warmstrong1955
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Re: Fan Motor Bearing

Post by warmstrong1955 » Fri Sep 27, 2013 5:19 pm

200 bucks ctwo???? Bet it sold in the Sears & Roebuck catalog for 3 bucks.....

amazing what happens to the price when you throw the word 'antique', or 'vintage' on it.

The one I fixed looked more like this one, just a lot bigger:
http://www.ebay.com/itm/Antique-Signal- ... 2c73049926

:)
Today's solutions are tomorrow's problems.

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Bill_Cook
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Re: Fan Motor Bearing

Post by Bill_Cook » Sun Sep 29, 2013 3:38 pm

I've tried to deal with the bearings on those late model fans. Soaking in lacquer thinner, scraping, wire brushing, and a variety of oils have yielded at best very temporary results.

I did have success lubing a PC processor fan with a very light oil.

After giving up on a box fan motor the stator caught my attention. It's rectangular, and the coil is on one side. After milling the opposite side out and removing some fat wires that went through the laminations it made a rather powerful magnet at 12 volts DC. (I feel comfortable doing electrical experimentation at lower voltages). It doesn't overheat, and works about as well as a MagnaFlux® magnet for crack detection except that it doesn't span as far.
Electromagnet.jpg
A free to me 16 gallon ShopVac® has a ball bearing on the blower end of the motor, but one of those fan motor spherical bushings in a bridge at the other end. The shaft didn't bind. but it would hammer around and walk the bushing around in the bridge. ShopVac® won't sell less than the whole motor. #2 chassis grease has solved the problem for now, but I doubt it will last. The solution may be another ball bearing. Hopefully it would fit in the bridge, and be aligned well enough. Of course making a new bridge would be child's play for just about any member of this forum, but this child has enough things he'd rather play at.

Does anyone here know where to get such a standardized part, and what it would be called?
BC

If there was only one way to do each machining job, the smell of sulphurized cutting oil smoke would have fewer fond memories.

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Bill_Cook
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Re: Fan Motor Bearing

Post by Bill_Cook » Sun Sep 29, 2013 4:04 pm

tornitore45 wrote:You could buy, today, a 1940 vintage, table fan with metal blades, those that can easily chop a finger trough a minimal protecting cage.
Roy Rogers had a TV show in the fifties. His sidekick Pat Brady worked in or owned a luncheonette. In one episode Pat really wanted to throw an egg into one of those fans to see what would happen. He didn't do it. I've been wondering about it since.
BC

If there was only one way to do each machining job, the smell of sulphurized cutting oil smoke would have fewer fond memories.

hammermill
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Re: Fan Motor Bearing

Post by hammermill » Sun Sep 29, 2013 4:15 pm

just for fyi the fat wires are called shading coils they produce a slight magnetic phase shift to get the motor turning

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tornitore45
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Re: Fan Motor Bearing

Post by tornitore45 » Sun Sep 29, 2013 5:00 pm

just for fyi the fat wires are called shading coils they produce a slight magnetic phase shift to get the motor turning
To be pedantic, they have no effect after a few millisecond that a DC source is applied. In other word they do not need to be removed if the plan is to supply DC to make a constant field electromagnet.

The fat turns do what they are supposed to do when powered with 60Hz AC.
Mauro Gaetano
in Austin TX

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warmstrong1955
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Re: Fan Motor Bearing

Post by warmstrong1955 » Sun Sep 29, 2013 5:34 pm

Bill_Cook wrote: In one episode Pat really wanted to throw an egg into one of those fans to see what would happen. He didn't do it. I've been wondering about it since.
Well...... I guess that's better than other things that have been known to hit the fan.......

:) Bill
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Richard_W
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Re: Fan Motor Bearing

Post by Richard_W » Sun Sep 29, 2013 6:00 pm

I used WD40 to wash out the bearing and let it dry for a day. Then oiled with10 WT a few drops spinning the blade slowly by hand. I could tell the reduced drag as I turned it. Then fired it up and it started on its own power and ran fine. Most people don't know that there are little slots to add a drop of oil now and then. Usually the first time I go to use it in the late spring.

Richard W.

scmods
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Re: Fan Motor Bearing

Post by scmods » Tue Oct 01, 2013 11:20 am

A popular motor design in the past for table fans and other low-powered applications was the shaded pole. This is what is shown in the electromagnet application photo. With DC, there is no fluctuating magnetic field to induce a counter EMF in the heavy wire, so its removal is operationally unnecessary. In it's original application, however, the fluctuating field of the AC powered coil induces a current in the heavy wire coil. This current creates it's own magnetic field which weakens the overall field in one part of the pole and causes the rotor to turn. If not particularly powerful or efficient, it is a simple and durable power source, and it is self-starting. The newer fans all seem to be multi-speed, and I am at a loss to see how multi-speed could be accomplished in a shaded pole design without losing the simplicity that is it's strong point.

The coil placement and airflow within the motor is such that over oiling is much less of a consideration than in an induction motor, where the windings are more or less exposed to excess oil. I personally prefer 3 in 1 oil, as it contains a solvent and is light weight (low drag). I believe they produce an oil specifically for motors. There is also Marvel Mystery Oil, which has been around a long time.

The time to re-lubricate is before the shaft starts squealing while there is still a little oil to draw the new oil in, so the suggestion of a drop or two at the start of each season is probably sound advice.

On the subject of your vacuum cleaner. I routinely grab every vacuum cleaner I find out for disposal, and salvage the motor. I have noticed that no matter what the brand of vacuum, the motor is almost invariably an Ametek brand. In almost every case, the motor is still good for experimentation, reapplication or parts. Never was the old adage "you get what you pay for" more clearly illustrated than in vacuum motors. With our throw away society and the general attitude of the retail industry, finding parts is a near impossibility, and the only alternative is to salvage or modify something else.

Along that line, the aforementioned vacuum cleaner strategy, and, additionally, photocopier salvage may prove to be a source of quality components with many possible uses. A typical photocopier contains a wealth of 8mm shafting, bronze and ball bearings, pulleys, gears, switches, sometimes miniature roller chain and sprockets. I used to get 'em when the kids were in high school to use for science projects. They're free, and they give you a real insight into current technology. Taking one apart is a real learning experience, and who among us couldn't use that?

Have fun

Bill Walck

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tornitore45
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Re: Fan Motor Bearing

Post by tornitore45 » Tue Oct 01, 2013 12:02 pm

Regarding disassembling experiences...
Some of my granchildren have an attention span measured in seconds, one one hand.
Recently I had one dissect an old fashion alarm clock, something just about any kid my generation has done.
After struggling with the absolute inaptitude of a seven year old to handle a screw driver and a pair of pliers he managed to have a really good experience as he took the clock apart and I explained the various functions of all levers, gears, spring and the balancer?? (do not know the english term for the oscillating mass acting as a pendulum-like time keeper).
Had to explain that a pendulum is not practical in a portable clock so an equivalent mechanism was invented.
Then we experimented with pendulums of various length and mass and plucked metal reed (hack saw blades)
The boy is smart and got the main physics idea but is sad that modern society tend to substitute real experiences with virtual ones.
Mauro Gaetano
in Austin TX

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