My journey repairing my table fans

This is how I choose a table fan.

I go to a department store with a wide selection of brands.
Like Aeon/Jusco.

I test a few for the throw it gives the air. I choose the top 3.
I run two of them face to face about 3 or 4 feet apart. I place
a piece of cardboard in between and move it around until it stays
vertical. I Leave this as an exercise for the reader to figure
out which is the more powerful fan.
I then pit the winner against the third fan.

This is how I arrived at the 55W Midea MF-16FT17NB
as the fan with the best bang for the buck.

My first Midea lasted a long time until suddenly in the middle
of the night it stopped working.

Measuring the resistance between live and neutral at the plug
pointed to a blown thermal fuse. Bummer.

So I bought another and recently it started running slower and
slower. Lubrication failure. But I caught it in time to save the
thermal fuse from blowing.

Both use sintered steel sleeve bearings which are not as porous
as sintered bronze and so die out earlier. Add to that a thermal
fuse buried deep in the windings and you get a lot of fans thrown
away as I see along my road. I never noticed this when I was a
child.

I will rescue my two Midea at a later opportunity with an NC
Normally Closed thermal switch mounted outside around the
middle stator bit. I must remember to ground this.

For the one that just failed, Singer and 3-in-one oil only lasted
one day. I remember trying engine oil in the past and that didn't
last either. I think it attracted a lot of dust. I have yet to
try Silicone oil.

Do you know of any fan manufacturer willing to sell their fan oil?
I remember researching the first electric fans and they had
built in oilers.

Anyway, the fan I just bought is the 55W Toshiba F-TSA20(G)MY.
It shapes the throw which can reach across the room. The main
selling point for me is the ball bearings instead of sintered
sleeves.

So no more headaches about lubrication for a long long time.

There was no felt pad oil reservoir in the Midea, just some
brown gunk paste. Built to fail?

Researching YouTube, it seems like many DIYers are replacing
their sleeves with 608Z ball bearings. I will go shopping
for those. In some countries, entreprenuers sell sleeves so
that your ball bearings fit your fan motor. I suppose you
could 3D print those. Some use 2-part epoxy or putty  and show
you tricks to align the rotor ends and stator.

In a pinch, you could try those from an abandoned/second hand
rollerblade wheel.
 
When I got the Midea, I investigated it with a power meter
and a cooking thermometer knowing that a day will come
when these baseline readings will come in useful.

I am sharing these here.
Setting 1/Low    40.33W 52.1 C
Setting 2/Medium 43.86W 55.1 C
Setting 3/High   53.12W 57.4 C {I rarely use this setting until
                               the lubrication started failing}
All measured against an ambient temperature of 32.9 C.

My testbed has been this Mistral Gyroaire.
This motor uses a 2A 250V 139C thermal fuse.
The coil measures 89.7 Ohms.
I managed to shoehorn a thermal switch.
If you look at the front view, I added a red ground wire
to the fan motor for safety.
I used engine oil which seems to attract a lot of dust.
I can't remember what the 130 C reading is about.

Here is a comparison. For domestic use, sintered bronze
is the superior choice in all measures except cost.

bronze VS steel

I consider it mala fide when they decided on sintered steel.
Shareholder wins, consumer and the environment loses.
I have 4 dogs in this fight. 3 Midea and former champion a
55W Faber FTF Tornado V 1611 BL.

PS If you are sufficiently alert, you might wonder why I
  wrote the measurements on the fan casing Upside Down.

  It is not a mistake. There is a simple answer --- I
  have a U-pipe - I think it used to be part of a deck chair -
  and the fan is suspended from it. It reduces
  the amplitude of the oscillation. You know, I wonder why
  nobody has yet to make the swing/speed/amplitude/loiter
  programmable. Cool one person then fast forward to another
  and stay there a bit longer . . .