Originally I had asked about the single speed of the Oreck
Professional Air cleaner: Apparently NOT the bearings in the fan
motor, but the motor itself.

Turn on cold and the squirrel cage fan motor has three speeds. ANd,
runs quitely and well in the slowest speed. After running a while, the
motor starts generating a light grinding noise, and only has one
speed. Plus, and this is pure subjective, the motor metal body seems
hot.

If the fan can run well for a while, it seems it may be possible to
repair this motor.

It seems two possibilities, getting hot opens something up, or getting
hot shorts something out. Since the construction of the motor is a
transformer-like winding, it seems likely that after heating up, the
coil has a shorted turn.

Does anybody have experience with the death throes of such a motor?

Robert

Can you determine how many leads are used for the motor, excluding an earth
ground lead?

Is there a low value capacitor assocated with the motor wiring? The
capacitor may possibly be more than one value, such as 2uF and 4uF.

A grinding noise may be unintended contact of moving parts. I would inspect
the motor's interior, and the blower section for signs of contact of moving
parts.

A low frequency growling noise may actually be a result of mildly worn
bearings.. a sort-of chatter that takes place as the shaft rattles in the
bearing I.D.. there is a specific term for this type of chatter, but I can't
remember it.
For a Hunter air cleaner that I use daily, standing the unit on it's side
eliminates the noise, which I'm certain is due to slightly worn bearings.
I've been using it for about 5 years, and it was neglectfully used when I
bought it.

With the motor shaft in a horizontal position, notice that the motor shaft
has a certain amount of axial movement (end play). At a point near the
center of this axial movement, apply radial force finger pressure to the
shaft or blower wheel to see if there is any significant amount of movement.
Any movement geater than barely noticeable, is bearing wear.

Small motor temperatures often seem to be exessive when checked by hand
contact. A thermocouple or other type of contact measuring device would
indicate if the motor is actually overheated.

In many types of air moving appliances, the air flow path passing over/thru
the motor provides adequate cooling if the motor vents and passages are
clear.
Additionally, most consumer appliances use motor designs with internal
temperature protection devices.. a self-resetting, temperature sensitive,
bi-metal type switch that will open at a temperature level below a dangerous
temperature.
A label on the motor generally states that the motor has temperature
protection.

Because the pass-thru air flow cools the motor, this also means that the
motor bearings are exposed to fine dirt that gets past the filter elements
in normal operation.
Periodic internal cleaning of the appliance and a drop of very light machine
oil to the bearings will go a long way to extend the effiiency and useful
life of the appliance.

Fine dust around bearings, even ball bearings, tends to wick the lubrication
out of the bearings.

I'm not saying that your motor doesn't have a thermally induced and/or
shorted turn fault, but conclusively finding out if it does, isn't a simple
matter.
If a capacitor is associated with the motor, that could be a more likely
source of the problem.

--
Cheers,
WB
..............


"Robert Macy" wrote in message
...
Originally I had asked about the single speed of the Oreck
Professional Air cleaner: Apparently NOT the bearings in the fan
motor, but the motor itself.

Turn on cold and the squirrel cage fan motor has three speeds. ANd,
runs quitely and well in the slowest speed. After running a while, the
motor starts generating a light grinding noise, and only has one
speed. Plus, and this is pure subjective, the motor metal body seems
hot.

If the fan can run well for a while, it seems it may be possible to
repair this motor.

It seems two possibilities, getting hot opens something up, or getting
hot shorts something out. Since the construction of the motor is a
transformer-like winding, it seems likely that after heating up, the
coil has a shorted turn.

Does anybody have experience with the death throes of such a motor?

Robert

On 19 jul, 17:18, Robert Macy wrote:
Originally I had asked about the single speed of the Oreck
Professional Air cleaner: Apparently NOT the bearings in the fan
motor, but the motor itself.

Turn on cold and the squirrel cage fan motor has three speeds. ANd,
runs quitely and well in the slowest speed. After running a while, the
motor starts generating a light grinding noise, and only has one
speed. *Plus, and this is pure subjective, the motor metal body seems
hot.

If the fan can run well for a while, it seems it may be possible to
repair this motor.

It seems two possibilities, getting hot opens something up, or getting
hot shorts something out. *Since the construction of the motor is a
transformer-like winding, it seems likely that after heating up, the
coil has a shorted turn.

Does anybody have experience with the death throes of such a motor?

Robert

Bad sleeve or ball bearings will cause the problem you are
experimenting. If they are worn out, they will allow the rotor to rub
against the armature as soon the armature gets hot and expands a
little, thus causing the grinding noise and slowing the entire motor.

In the other hand a winding failure is an one time event: once a
shorts develops in a coil the entire winding gets burnt.

On Sun, 19 Jul 2009 14:18:06 -0700, Robert Macy wrote:

Does anybody have experience with the death throes of such a motor?
Robert

I do, but, it was the bearings. I don't know about the air cleaner you
mention, although Oreck advertised very heavily on radio programs I used
to listen to.

Can you turn off power and rotate the fan blades with a finger? Plainly,
they should coast.

I won't discount your hypothesis about a shorted turn, though.

A while back, I bought a very-popular Honeywell-branded three-speed
tabletop fan, a Vornado knock-off, and its bearings had run low on oil.
It has an alloy steel shaft, probably a variety of Ni Cr, and porous
bronze self-aligning bearings surrounded by oil-reservoir wicks; they
were "dry".

The motor normally ran hot, est. 125 or 150 C. I tried every lubricant I
could easily obtain except synthetic car-engine oil, and none lasted more
than maybe (at most) a week. Apparently factory lube was a high-tech
synthetic with very low volatility even when hot. I do hope that such a
lube is available in small quantities, such as 3 oz or 100 cc (probably
not equivalent, btw.)

One summer night, I had the fan on, and awoke to the odor of overheated
insulation. The bearings had "frozen" (they could still be disassembled
and cleaned), and a thermal fuse inside the windings had opened. It was
near the surface, but covered by the insulation.

I decided that it would be foolhardy to try to use the fan any more, and
put most of it out for recycling, but saved the rotor, shaft, and
bearings just for kicks. (Nice specimen for explaining commonplace tech.
to somebody who hasn't seen such things. I feel that we don't tend take
apart unwanted stuff any more, although I'm heartened by transparent
plastic housings that let us see innards. a rather-new trend).

Interesting that this fan is so popular that the dies for injection-
molding the blades have eroded badly enough to unbalance the blades
significantly. I also saved the blades, which were nicely balanced.
I have no confidence at all that if I returned one of these fans for
excessive vibration that doing so would cause them to do something about
it, other than to send me another with the same problem.

Fwiw, I was given a Nidec-Torin Alpha V square computer-type fan rated
for 240 V operation. It has advanced plain hydrodynamic (surely not
"hydrostatic"?) bearings, in which motion probably drags the oil into
narrowing cylindrical wedge-like cavities so there's no metal-to metal
contact. The lubricant (and seals) must be simply superb. Run at 120V 60
Hz, the motor has a whopping amount of induction-motor slip, but of
course it runs at cucumber temperature. I know that it will outlast me
(I'm 73), even if I last like Andres Segovia or Dan Schorr, God bless him.

I use it at night while sleeping as a very-gentle, very quiet circulator,
so that I don't re-breathe my own stale air.

After it's been running, the coast-down is so long that you'd swear that
it has ball bearings.

Btw, those 3-speed induction-motor fans have tapped windings, with taps
very carefully chosen so that the curves of motor speed and torque
correlate with fan drive torque vs. speed; both just have to be
nonlinear. Remove a fan blade, and the motor runs at all speed settings
with low slip, but different torques; you can use your fingers briefly as
a load brake if the shaft is smooth and it's a small fan. (I don't try to
slow it to half speed or so; just get an idea of running torque, or else
grip the shaft tightly enough to stall it, then switch on. Of course,
stall torque differs.)

(Slip? I do hope there's a good explanation somewhere. Try Wikipedia on
electric motors. I'm not ambitious enough just now to explain it
properly; it's the difference between synch. speed and operating speed of
a squirrel-cage induction motor, the kind you find everywhere; they run
quiet, and not especially fast.)


HTH!

=+=+=

As to the HP printer: I used to work in a very small computer store,
sales and service, run by a guy so generous-spirited I considered him to
be a "prince by [virtue of] merit". More about that, some other time.

A fellow brought in an HP inkjet of the 600 or 700 series, and its main
printhead/ink cartridge (HP lingo: "pen") carrier sliding bearing had run
dry. My boss used WD-40, against my gentle advice. Surely enough, it had
the same problem, one day later.

(Perhaps WD-40 is one of the most-misused products since 3-in-1 oil was
based on vegetable oil that polymerized into varnish, like linseed oil.)

I ran the store while he worked as a sysadmin., and called HP printer
service. They stonewalled fanatically. When I told HP he'd used WD-40, he
gave a classic "eeeeuuuuuwwww". No more info. When the p. by m. came in
at the end of the day (or else next chance) he called HP and gave them
the blazes. He had HP cert. for laser printers (he loved LJ 3's --
wonderfully built), and was therefore, in a sense, an insider, at least
regarding printers. HP, contrite, sent about four syringes of an Anderol
synthetic lubricant, and it worked marvelously.

Talk about "secret lubricants"!

Yrs trly wants to get a small quantity of grease for plastic mechanisms,
but hasn't really looked.

--
Nicabod =+= Waltham, Mass.

On Jul 19, 4:07*pm, Nicholas Bodley wrote:
On Sun, 19 Jul 2009 14:18:06 -0700, Robert Macy wrote:

Does anybody have experience with the death throes of such a motor?
Robert

I do, but, it was the bearings. I don't know about the air cleaner you
mention, although Oreck advertised very heavily on radio programs I used
to listen to.

Can you turn off power and rotate the fan blades with a finger? Plainly,
they should coast.

I won't discount your hypothesis about a shorted turn, though.

A while back, I bought a very-popular Honeywell-branded three-speed
tabletop fan, a Vornado knock-off, and its bearings had run low on oil.
It has an alloy steel shaft, probably a variety of Ni Cr, and porous
bronze self-aligning bearings surrounded by oil-reservoir wicks; they
were "dry".

The motor normally ran hot, est. 125 or 150 C. I tried every lubricant I
could easily obtain except synthetic car-engine oil, and none lasted more
than maybe (at most) a week. Apparently factory lube was a high-tech
synthetic with very low volatility even when hot. I do hope that such a
lube is available in small quantities, such as 3 oz or 100 cc (probably
not equivalent, btw.)

One summer night, I had the fan on, and awoke to the odor of overheated
insulation. The bearings had "frozen" (they could still be disassembled
and cleaned), and a thermal fuse inside the windings had opened. It was
near the surface, but covered by the insulation.

I decided that it would be foolhardy to try to use the fan any more, and
put most of it out for recycling, but saved the rotor, shaft, and
bearings just for kicks. (Nice specimen for explaining commonplace tech.
to somebody who hasn't seen such things. I feel that we don't tend take
apart unwanted stuff any more, although I'm heartened by transparent
plastic housings that let us see innards. a rather-new trend).

Interesting that this fan is so popular that the dies for injection-
molding the blades have eroded badly enough to unbalance the blades
significantly. I also saved the blades, which were nicely balanced.
I have no confidence at all that if I returned one of these fans for
excessive vibration that doing so would cause them to do something about
it, other than to send me another with the same problem.

Fwiw, I was given a Nidec-Torin Alpha V square computer-type fan rated
for 240 V operation. It has advanced plain hydrodynamic (surely not
"hydrostatic"?) bearings, in which motion probably drags the oil into
narrowing cylindrical wedge-like cavities so there's no metal-to metal
contact. The lubricant (and seals) must be simply superb. Run at 120V 60
Hz, the motor has a whopping amount of induction-motor slip, but of
course it runs at cucumber temperature. I know that it will outlast me
(I'm 73), even if I last like Andres Segovia or Dan Schorr, God bless him..

I use it at night while sleeping as a very-gentle, very quiet circulator,
so that I don't re-breathe my own stale air.

After it's been running, the coast-down is so long that you'd swear that
it has ball bearings.

Btw, those 3-speed induction-motor fans have tapped windings, with taps
very carefully chosen so that the curves of motor speed and torque
correlate with fan drive torque vs. speed; both just have to be
nonlinear. Remove a fan blade, and the motor runs at all speed settings
with low slip, but different torques; you can use your fingers briefly as
a load brake if the shaft is smooth and it's a small fan. (I don't try to
slow it to half speed or so; just get an idea of running torque, or else
grip the shaft tightly enough to stall it, then switch on. Of course,
stall torque differs.)

(Slip? I do hope there's a good explanation somewhere. Try Wikipedia on
electric motors. I'm not ambitious enough just now to explain it
properly; it's the difference between synch. speed and operating speed of
a squirrel-cage induction motor, the kind you find everywhere; they run
quiet, and not especially fast.)

HTH!

=+=+=

As to the HP printer: I used to work in a very small computer store,
sales and service, run by a guy so generous-spirited I considered him to
be a "prince by [virtue of] merit". More about that, some other time.

A fellow brought in an HP inkjet of the 600 or 700 series, and its main
printhead/ink cartridge (HP lingo: "pen") carrier sliding bearing had run
dry. My boss used WD-40, against my gentle advice. Surely enough, it had
the same problem, one day later.

(Perhaps WD-40 is one of the most-misused products since 3-in-1 oil was
based on vegetable oil that polymerized into varnish, like linseed oil.)

I ran the store while he worked as a sysadmin., and called HP printer
service. They stonewalled fanatically. When I told HP he'd used WD-40, he
gave a classic "eeeeuuuuuwwww". No more info. When the p. by m. came in
at the end of the day (or else next chance) he called HP and gave them
the blazes. He had HP cert. for laser printers (he loved LJ 3's --
wonderfully built), and was therefore, in a sense, an insider, at least
regarding printers. HP, contrite, sent about four syringes of an Anderol
synthetic lubricant, and it worked marvelously.

Talk about "secret lubricants"!

Yrs trly wants to get a small quantity of grease for plastic mechanisms,
but hasn't really looked.

--
Nicabod =+= Waltham, Mass.

Thank you every one for replying!

Does anyone have a schematic for the
Oreck XL Professional Air Purifier?

Regarding bearings:

I, too, learned the hard way about the ills of WD-40. I found Singer
Sewing Machine oil to work very well and if mixed with lighter fluid
it seemed to have the same penetrating power of WD-40 [without the
varnish effect later] *and* the naptha would evaporate with time
leaving nice consistency oil.

The fan is a horizontal squirrel cage in a separate compartment from
the motor. Without power the fan can be spun by hand and takes a
great deal of time to coast to a stop. Also, spinning makes no sound.
With power [and the light grounding noise] the fan is spinning, and
has noticeable torque when the fan is stopped with my hand.

*****ARRRRG!!!!!

Nothing more valuable than experimentation! Just now I purposely
stopped the fan and could hear the grinding noise continuing. Just
for 'some reason' I touched the butt end of the motor to find it was
still turning with the fan stopped! This motor drive path has a
CLUTCH!!! to the fan [may be NOT on purpose]. The noise is the sound
the 'clutch' makes as it's slipping!

That also explains why there is only one speed. At higher speed
setting the grinding moves up a bit in pitch but the fan never speeds
up, because, again, that clutch is slipping!

This may not be a clutch by design, but rather a rubber 'alignment'
shaft. When new, the press fit kept the fan and motor locked
together, but with age and rubber deteriorating from actions of oil,
the press fit is slipping. Now to lock the fan to the motor shaft???

Thank you all.

Should I use super glue on the rubber?

Robert

On Sun, 19 Jul 2009 17:42:43 -0700 (PDT), Robert Macy
wrote:

This may not be a clutch by design, but rather a rubber 'alignment'
shaft. When new, the press fit kept the fan and motor locked
together, but with age and rubber deteriorating from actions of oil,
the press fit is slipping. Now to lock the fan to the motor shaft???

Thank you all.

Should I use super glue on the rubber?

No. Superglue is brittle and will crack loose the first time the fan
hits something. Start by tearing the rubber shaft (clutch?) apart and
cleaning it and the shaft. Remove all the old oil and goo. Use
alcohol to make the rubber swell a bit. Make sure the shaft is clean
and oil free. There should be enough friction to make it work. If
not, try some rubber belt no-slip compound used for improving the
friction in tape recorders, record players, and other rubber parts.
Avoid xylene (dimethylbenzene) based "rubber restorer" solutions as
they will soften the rubber but also probably make the shaft slip.

For high temperature lubricant, use a SOLID lubricant, not liquid.
Yeah, I know it doesn't penetrate, but that's the price you pay for
high temp. See:
http://www.tribology-abc.com/abc/solidlub.htm
for clues on different types. If you're lazy, try graphite lock lube
(the powder variety, not the messy stuff mixed with light oil). Keep
the lube away from the rubber "clutch" as it will make it slip.

I do some HP LaserJet printer repairs. The older models (LJII, LJIII
and LJ4) required some grease on the drive gears and a few metal gears
on shafts. When needed, I used lithium white auto grease, which is
probably not the right stuff, but worked well. However, all the other
nylon gears were self lubricating. The best way to make a huge mess
was to lube all the gears. I'm not 100.0% sure, but I believe that
current HP printers (LJ42xx, 43xx, etc) do not require any
lubrication. I sometimes use "rubber restorer" on the paper feed
rollers, but only if the paper is slipping and I don't have a
replacement roller or foot.



--
Jeff Liebermann
150 Felker St #D http://www.LearnByDestroying.com
Santa Cruz CA 95060 http://802.11junk.com
Skype: JeffLiebermann AE6KS 831-336-2558

On Sun, 19 Jul 2009 14:18:06 -0700, Robert Macy wrote:

Originally I had asked about the single speed of the Oreck Professional
Air cleaner: Apparently NOT the bearings in the fan motor, but the motor
itself.

Turn on cold and the squirrel cage fan motor has three speeds. ANd, runs
quitely and well in the slowest speed. After running a while, the motor
starts generating a light grinding noise, and only has one speed. Plus,
and this is pure subjective, the motor metal body seems hot.

some trimmed

Robert


The problem you are describing sounds more like failing pre oiled bronze
bearings. They loose the oil impregnation and then gall, re-oiling them
once they have galled and begun grinding has no effect.

I have encountered these many times on air cleaners and item that run for
long periods built with cheap motors that really were never rated for
continuous duty.

There was one exception I ran into, it was one that used a squrrel cage
that had a bearing on it that supported the end away from the motor and it
was bad like a motor bearing.

The only solution is replace the motor or the unit and the motor generally
costs more that the unit.

Gnack

On Sun, 19 Jul 2009 14:18:06 -0700 (PDT), Robert Macy
wrote:

Originally I had asked about the single speed of the Oreck
Professional Air cleaner: Apparently NOT the bearings in the fan
motor, but the motor itself.

Turn on cold and the squirrel cage fan motor has three speeds. ANd,
runs quitely and well in the slowest speed. After running a while, the
motor starts generating a light grinding noise, and only has one
speed. Plus, and this is pure subjective, the motor metal body seems
hot.

Tight clearances on the rotor, heat expands it, and it binds? I'd
guess it gets hot because of a shorted turn in the stator, but that's
a guess. And, how did you eliminate the bearings from the equation?
Does the motor spin freely when hot?


If the fan can run well for a while, it seems it may be possible to
repair this motor.

It seems two possibilities, getting hot opens something up, or getting
hot shorts something out. Since the construction of the motor is a
transformer-like winding, it seems likely that after heating up, the
coil has a shorted turn.

Does anybody have experience with the death throes of such a motor?

Robert

On Sun, 19 Jul 2009 18:07:35 -0500, Nicholas Bodley
wrote:

...
The motor normally ran hot, est. 125 or 150 C. I tried every lubricant I
could easily obtain except synthetic car-engine oil, and none lasted more
than maybe (at most) a week. Apparently factory lube was a high-tech
synthetic with very low volatility even when hot. I do hope that such a
lube is available in small quantities, such as 3 oz or 100 cc (probably
not equivalent, btw.)


Next time try light high-temperature wheel bearing grease. The stuff I
have is blue in color, flows reasonably well, works wonderfully,
doesn't burn off, and lasts.

As you note: oil just plain doesn't work. I've also tried synthetic
motor oil, and didn't have good results with it either. The only thing
that works for me is that wheel bearing grease. (look for some that
says 'good for disk brake wheel bearings' or something similar.

Doesn't the Oreck have some sort of super-long warranty? Its products are so
expensive there wouldn't be much point buying them otherwise.

On Jul 19, 6:56*pm, Jeff Liebermann wrote:
On Sun, 19 Jul 2009 17:42:43 -0700 (PDT), Robert Macy

wrote:
This may not be a clutch by design, but rather a rubber 'alignment'
shaft. *When new, the press fit kept the fan and motor locked
together, but with age and rubber deteriorating from actions of oil,
the press fit is slipping. *Now to lock the fan to the motor shaft???

Thank you all.

Should I use super glue on the rubber?

No. *Superglue is brittle and will crack loose the first time the fan
hits something. *Start by tearing the rubber shaft (clutch?) apart and
cleaning it and the shaft. *Remove all the old oil and goo. *Use
alcohol to make the rubber swell a bit. *Make sure the shaft is clean
and oil free. *There should be enough friction to make it work. *If
not, try some rubber belt no-slip compound used for improving the
friction in tape recorders, record players, and other rubber parts.
Avoid xylene (dimethylbenzene) based "rubber restorer" solutions as
they will soften the rubber but also probably make the shaft slip.

For high temperature lubricant, use a SOLID lubricant, not liquid.
Yeah, I know it doesn't penetrate, but that's the price you pay for
high temp. *See:
http://www.tribology-abc.com/abc/solidlub.htm
for clues on different types. *If you're lazy, try graphite lock lube
(the powder variety, not the messy stuff mixed with light oil). *Keep
the lube away from the rubber "clutch" as it will make it slip.

I do some HP LaserJet printer repairs. *The older models (LJII, LJIII
and LJ4) required some grease on the drive gears and a few metal gears
on shafts. *When needed, I used lithium white auto grease, which is
probably not the right stuff, but worked well. *However, all the other
nylon gears were self lubricating. *The best way to make a huge mess
was to lube all the gears. *I'm not 100.0% sure, but I believe that
current HP printers (LJ42xx, 43xx, etc) do not require any
lubrication. *I sometimes use "rubber restorer" on the paper feed
rollers, but only if the paper is slipping and I don't have a
replacement roller or foot.

--
Jeff Liebermann * *
150 Felker St #D * *http://www.LearnByDestroying.com
Santa Cruz CA 95060http://802.11junk.com
Skype: JeffLiebermann * * AE6KS * *831-336-2558

Thank you for your reply. Great suggestions. Especially the rubber
belt dressing to increase friction.

The 'light grinding' noise comes when the motor shaft starts slipping
in the rubber transfer to the fan. It seems there are four small
ridges on the metal to help 'bite' into the rubber. So, when it
starts slipping it makes a noise.

Here is the failure scenario to date:
System does run fairly cool at around 60C [This is based upon my
experience at not being able to hold my finger on metal above 60C for
more than 10 seconds]. All bearings are smooth and oiled, also
running cool. Fan whether hot or cold turns easily coasting slowly to
stop. Oil however migrated from the motor bearing, along the shaft,
and into the rubber transfer and that is now slipping.

I tried to remove the fan from the motor shaft, but could not. I
completely lifted the motor/fan out of the unit, yet the rubber won't
slide off the end of the motor shaft allowing access to clean all
out. If there is a retaining clip of some kind, I can't see it, and
worse, not be able to get access to it. Since the fan is squirrel
cage, there is no way to gain access to a clip inside the 'cylinder'
with my tools.

Can I still try cleaning with alcohol? Will that dissolve any of the
oil residue inside the rubber/metal junction?

Change of subject: Not for this problem but for other 'clean out old
oil' problems, did you ever try transmission fluid? I once had a
mechanic tell me "to flush an oil system with one quart of
transmission fluid mixed in the oil to remove all the ill effects of
someone using STP. He said, don't drive it, simply heat the engine up
and change the oil mix out, and replace with oil, heat up engine
again, and replace with oil. That will clean all gunk out."

But, transmission fluid is a high temperature oil isn't it?

Robert

On Mon, 20 Jul 2009 08:55:17 -0700, Robert Macy wrote:

On Jul 19, 6:56*pm, Jeff Liebermann wrote:
On Sun, 19 Jul 2009 17:42:43 -0700 (PDT), Robert Macy

wrote:
This may not be a clutch by design, but rather a rubber 'alignment'
shaft. *When new, the press fit kept the fan and motor locked
together, but with age and rubber deteriorating from actions of oil,
some clipped

The 'light grinding' noise comes when the motor shaft starts slipping in
the rubber transfer to the fan. It seems there are four small ridges
on the metal to help 'bite' into the rubber. So, when it starts
slipping it makes a noise.

Here is the failure scenario to date: System does run fairly cool at
around 60C [This is based upon my experience at not being able to hold
my finger on metal above 60C for more than 10 seconds]. All bearings
are smooth and oiled, also running cool. Fan whether hot or cold turns
easily coasting slowly to stop. Oil however migrated from the motor
bearing, along the shaft, and into the rubber transfer and that is now
slipping.

I tried to remove the fan from the motor shaft, but could not. I
completely lifted the motor/fan out of the unit, yet the rubber won't
slide off the end of the motor shaft allowing access to clean all out.
If there is a retaining clip of some kind, I can't see it, and worse,
not be able to get access to it. Since the fan is squirrel cage, there
is no way to gain access to a clip inside the 'cylinder' with my tools.


But, transmission fluid is a high temperature oil isn't it?

Robert

Yes transmission fluid is a grade of oil and is safe for neopreme Orings
not regular rubber.

Your Oric sounds a lot like some Sears branded electrostatic cleaners that
I had once the fan was what is refered to as a reever style about 8 inches
long and mounted in a bronze bearing block on one end and a heavy rubber
grommet on the other. The rubber is simply to allow easy alignment between
the motor and fan, A flex coupler if you think about it so that the case
alignment is not critical.

The bearing on the end of the fam was what failed since it was quite small
7/16" ID (had I known this before it failed oiling would have saved it)
Like your case the fan would run at low speed for a short period before
locking up but woul not run at any speed higher than low.

You probably have a bad beaing on the end of thr fan away from the motor
Robert. Here is what happens with sleve bearings that are "oillite" bronze
used in most places. They exhaust the actual impregnated lubricant and
gall. This is not apperent until the friction heats up the bearing or the
fan tries to run beyond the point where friction balances torque. ( this
effect is most often seen in chesp computer cooing fans that rev up to
about haf or less of rated speed and start squealing and slow down).

On Jul 20, 10:18*am, Gnack Nol wrote:
On Mon, 20 Jul 2009 08:55:17 -0700, Robert Macy wrote:
On Jul 19, 6:56*pm, Jeff Liebermann wrote:
On Sun, 19 Jul 2009 17:42:43 -0700 (PDT), Robert Macy

wrote:
This may not be a clutch by design, but rather a rubber 'alignment'
shaft. *When new, the press fit kept the fan and motor locked
together, but with age and rubber deteriorating from actions of oil,

some clipped





The 'light grinding' noise comes when the motor shaft starts slipping in
the rubber *transfer to the fan. *It seems there are four small ridges
on the metal to help 'bite' into the rubber. *So, when it starts
slipping it makes a noise.

Here is the failure scenario to date: System does run fairly cool at
around 60C [This is based upon my experience at not being able to hold
my finger on metal above 60C for more than 10 seconds]. *All bearings
are smooth and oiled, also running cool. *Fan whether hot or cold turns
easily coasting slowly to stop. *Oil however migrated from the motor
bearing, along the shaft, and into the rubber transfer and that is now
slipping.

I tried to remove the fan from the motor shaft, but could not. *I
completely lifted the motor/fan out of the unit, yet the rubber won't
slide off the end of the motor shaft allowing access to clean all out.
If there is a retaining clip of some kind, I can't see it, and worse,
not be able to get access to it. *Since the fan is squirrel cage, there
is no way to gain access to a clip inside the 'cylinder' with my tools.

But, transmission fluid is a high temperature oil isn't it?

Robert

Yes transmission fluid is a grade of oil and is safe for neopreme Orings
not regular rubber.

Your Oric sounds a lot like some Sears branded electrostatic cleaners that
I had once the fan was what is refered to as a reever style about 8 inches
long and mounted in a bronze bearing block on one end and a heavy rubber
grommet on the other. The rubber is simply to allow easy alignment between
the motor and fan, A flex coupler if you think about it so that the case
alignment is not critical.

The bearing on the end of the fam was what failed since it was quite small
7/16" ID (had I known this before it failed oiling would have saved it)
Like your case the fan would run at low speed for a short period before
locking up but woul not run at any speed higher than low.

You probably have a bad beaing on the end of thr fan away from the motor
Robert. Here is what happens with sleve bearings that are "oillite" bronze
used in most places. They exhaust the actual impregnated lubricant and
gall. This is not apperent until the friction heats up the bearing or the
fan tries to run beyond the point where friction balances torque. ( this
effect is most often seen in chesp computer cooing fans that rev up to
about haf or less of rated speed and start squealing and slow down).- Hide quoted text -

- Show quoted text -

That description is exactly correct. Except the bearing is so good
that hot or cold spinning the fan and powering off takes a long time
to coast to a stop. Bearing is in good shape.

However, the motor bearing oil migrated over to the rubber grommet.
And I can't disassemble it to clean it.

Robert

Jeff Liebermann wrote:
I do some HP LaserJet printer repairs. The older models (LJII, LJIII
and LJ4) required some grease on the drive gears and a few metal gears
on shafts. When needed, I used lithium white auto grease, which is
probably not the right stuff, but worked well.

White lithium grease is fine for those parts. That's what Canon use
themselves for that purpose.

However, all the other
nylon gears were self lubricating. The best way to make a huge mess
was to lube all the gears. I'm not 100.0% sure, but I believe that
current HP printers (LJ42xx, 43xx, etc) do not require any
lubrication. I sometimes use "rubber restorer" on the paper feed
rollers, but only if the paper is slipping and I don't have a
replacement roller or foot.

I use acetone (or nail-polish remover) to take the 'shine' off paper
rollers, which gives you years more life out of them. It's also good for
the separation pad in the paper pickup assembly for laser printers & the
document pickup assembly in faxes.

--
W
. | ,. w , "Some people are alive only because
\|/ \|/ it is illegal to kill them." Perna condita delenda est
---^----^---------------------------------------------------------------

Gnack Nol wrote:
The problem you are describing sounds more like failing pre oiled bronze
bearings. They loose the oil impregnation and then gall, re-oiling them
once they have galled and begun grinding has no effect.

I've been told that cooking the bearings & dunking them in light oil
fixes that, but I've never actually tried it myself, so YMMV.

Another trick with worn phosphor-bronze bearings is to build up the
bronze with a coating of solder, which has worked well for me when it
hasn't been possible to replace the bearing.

--
W
. | ,. w , "Some people are alive only because
\|/ \|/ it is illegal to kill them." Perna condita delenda est
---^----^---------------------------------------------------------------

On Tue, 21 Jul 2009 17:57:15 +1000, Bob Larter
wrote:

Jeff Liebermann wrote:
I do some HP LaserJet printer repairs. The older models (LJII, LJIII
and LJ4) required some grease on the drive gears and a few metal gears
on shafts. When needed, I used lithium white auto grease, which is
probably not the right stuff, but worked well.

White lithium grease is fine for those parts. That's what Canon use
themselves for that purpose.

Thanks. I wasn't sure it was the right stuff.

However, all the other
nylon gears were self lubricating. The best way to make a huge mess
was to lube all the gears. I'm not 100.0% sure, but I believe that
current HP printers (LJ42xx, 43xx, etc) do not require any
lubrication. I sometimes use "rubber restorer" on the paper feed
rollers, but only if the paper is slipping and I don't have a
replacement roller or foot.

I use acetone (or nail-polish remover) to take the 'shine' off paper
rollers, which gives you years more life out of them. It's also good for
the separation pad in the paper pickup assembly for laser printers & the
document pickup assembly in faxes.

Nope. I've had problems with acetone warping the plastic spindle
under the rubber feed rollers. It works, but is far too strong a
solvent. If the rubber is impregnated with oil (to keep it soft), the
acetone will dry it out, causing the rubber surface to get hard after
about a month or two of use. I switched to a xylene based solvent:
http://www.fixyourownprinter.com/specials/misc/chemicals/S03
which doesn't have the problem. One problem is that it's a really
foul smelling cleaner. I have to do the cleaning outdoors, and store
the can inside two zip lock bags. I threw some towel paper with some
of the stuff on it, and it stunk up the office for days.

There are also some nasty health effects for Xylene, so I user rubber
gloves and plenty of fresh air. I've had dizziness and nausea from
the stuff when I wasn't careful:
http://www.eco-usa.net/toxics/xylene.shtml#health

I don't think it will make much difference for the rubber clutch in
this motor. Alcohol or whatever is probably sufficient to clean it.

Also, it didn't take much to find a replacement motor:
http://www.totalvac.com/accessory/parts/097553501.html
However, no sign of the rubber clutch.


--
Jeff Liebermann
150 Felker St #D http://www.LearnByDestroying.com
Santa Cruz CA 95060 http://802.11junk.com
Skype: JeffLiebermann AE6KS 831-336-2558

Jeff Liebermann wrote:
On Tue, 21 Jul 2009 17:57:15 +1000, Bob Larter
wrote:

Jeff Liebermann wrote:
I do some HP LaserJet printer repairs. The older models (LJII, LJIII
and LJ4) required some grease on the drive gears and a few metal gears
on shafts. When needed, I used lithium white auto grease, which is
probably not the right stuff, but worked well.
White lithium grease is fine for those parts. That's what Canon use
themselves for that purpose.

Thanks. I wasn't sure it was the right stuff.

However, all the other
nylon gears were self lubricating. The best way to make a huge mess
was to lube all the gears. I'm not 100.0% sure, but I believe that
current HP printers (LJ42xx, 43xx, etc) do not require any
lubrication. I sometimes use "rubber restorer" on the paper feed
rollers, but only if the paper is slipping and I don't have a
replacement roller or foot.
I use acetone (or nail-polish remover) to take the 'shine' off paper
rollers, which gives you years more life out of them. It's also good for
the separation pad in the paper pickup assembly for laser printers & the
document pickup assembly in faxes.

Nope. I've had problems with acetone warping the plastic spindle
under the rubber feed rollers. It works, but is far too strong a
solvent.

If you're warping the spindle, you're using too much acetone. Dip a
coarse rag in the acetone, & rub the roller with it. You do need to be
careful to keep it away from the plastic.

If the rubber is impregnated with oil (to keep it soft), the
acetone will dry it out, causing the rubber surface to get hard after
about a month or two of use.

That's never been a problem for me. I've serviced a heap of printers
under service contracts, & never had any of these fixes come back to
haunt me.

I switched to a xylene based solvent:
http://www.fixyourownprinter.com/specials/misc/chemicals/S03
which doesn't have the problem. One problem is that it's a really
foul smelling cleaner. I have to do the cleaning outdoors, and store
the can inside two zip lock bags. I threw some towel paper with some
of the stuff on it, and it stunk up the office for days.

There are also some nasty health effects for Xylene,

You're not kidding. No way would I go near that ****. I'll stick with
acetone, thanks all the same.


--
W
. | ,. w , "Some people are alive only because
\|/ \|/ it is illegal to kill them." Perna condita delenda est
---^----^---------------------------------------------------------------

On Jul 19, 5:42*pm, Robert Macy wrote:
...snip...
Nothing more valuable than experimentation! *Just now I purposely
stopped the fan and could hear the grinding noise continuing. *Just
for 'some reason' I touched the butt end of the motor to find it was
still turning with the fan stopped! *This motor drive path has a
CLUTCH!!! to the fan [may be NOT on purpose]. *The noise is the sound
the 'clutch' makes as it's slipping!

That also explains why there is only one speed. At higher speed
setting the grinding moves up a bit in pitch but the fan never speeds
up, because, again, that clutch is slipping!

This may not be a clutch by design, but rather a rubber 'alignment'
shaft. *When new, the press fit kept the fan and motor locked
together, but with age and rubber deteriorating from actions of oil,
the press fit is slipping. *Now to lock the fan to the motor shaft???

Thank you all.

Should I use super glue on the rubber?

Robert

FINALLY!

Simply removed the grommet, cleaned under it, put some tacky glue
stick on the shaft, reassembled, and VOILA! Working great now.

Removing the grommet was the key. The fan comes out easily, but
remains attached to the motor shaft, so remove the mounting screws for
the motor and tilt the assembly up out of the mounting points. Then
DON'T PULL instead use a pair of plier tips to gently wedge the rubber
off the retaining ring and PUSH the fan away from the motor. For me,
it popped right off, probably due to all that oil in there. That
allowed me to clean the squirrel cage fan blades in a sink of
detergent and wipe off the motor shaft. After sliding paper towel
rolled up to the size of the shaft through the rubber several times [a
lot of residue came out] I then used the only tacky stuff around, a
glue stick, rubbed it on the shaft, reassembled, and let it set a few
hours. Compared to before the friction between the motor and the fan
was now incredible. So turned it on. And all works well. Very
quiet, too.

Thank you to all who jumped in to help. And especially thank you
about suggesting acetone on my HP DeskJet rollers.

Robert

Robert Macy wrote:
Thank you to all who jumped in to help. And especially thank you
about suggesting acetone on my HP DeskJet rollers.

Glad we could help.

--
W
. | ,. w , "Some people are alive only because
\|/ \|/ it is illegal to kill them." Perna condita delenda est
---^----^---------------------------------------------------------------

On Mon, 27 Jul 2009 23:35:36 +1000, Bob Larter wrote:

If you're warping the spindle, you're using too much acetone. Dip a
coarse rag in the acetone, & rub the roller with it. You do need to be
careful to keep it away from the plastic.

If the rubber is impregnated with oil (to keep it soft), the
acetone will dry it out, causing the rubber surface to get hard after
about a month or two of use.

That's never been a problem for me. I've serviced a heap of printers
under service contracts, & never had any of these fixes come back to
haunt me.

Bob,

Most helpful to know! Many thanks. I have an older HP LJ (7?) that won't
pick a single sheet. There have been refurb kits, but I haven't been keen
on following through; access is from the back, and judging by the online
(poor quality) images, it's quite involved. It would be easier, I'd
expect, to resurface than to replace parts.

=+=+=

I once helped a friend (a lady geek) clean her Oki impact dot-matrix
printer. The print head drive motor was mounted with the print head (!),
and a pinion engaged a clear plastic rack that extended across the
operating space inside. Thinking that isopropyl alcohol (but, rubbing
alcohol, which contains other stuff) would be OK to clean the rack, we
were both amazed and horrified to see the plastic craze and disintegrate
*as we watched*!

As I recall, she contacted the regional Oki rep., and he sent a free
replacement, which was easy to install. Credit Oki for being decent.

--
Nicabod =+= Waltham, Mass.
who really should properly dispose
of that metal can of Freon TF; it's
never used any more. Was nice stuff...