Air Conditioner Fan Problem

[William R. Walsh]

Hello all...

I trashpicked an 8,000 BTU Carrier air conditioner. It seems to be in decent
shape apart from rotted out "accordion sides" on both ends. (Does anyone
know where to get those alone?) However, the fan motor seems to have some
kind of a problem. It will run fine for a while and then it will start
dragging down until it stops turning altogether. However, giving it a push
with my hand after it has stalled will get it moving again. Obviously I
don't think it is safe to run this unit unattended.

At no point does the motor seem to have actually siezed up, so I'm at a
loss. I even took it apart, cleaned it off and oiled the bearings. Any
thoughts? Best to put it back out on the street?

William

 

[Sam Goldwasser]

"William R. Walsh" <newsgroups1@idontwantjunqueemail.walshcomptech.com> writes:

Hello all...

I trashpicked an 8,000 BTU Carrier air conditioner. It seems to be in decent
shape apart from rotted out "accordion sides" on both ends. (Does anyone
know where to get those alone?) However, the fan motor seems to have some
kind of a problem. It will run fine for a while and then it will start
dragging down until it stops turning altogether. However, giving it a push
with my hand after it has stalled will get it moving again. Obviously I
don't think it is safe to run this unit unattended.

At no point does the motor seem to have actually siezed up, so I'm at a
loss. I even took it apart, cleaned it off and oiled the bearings. Any
thoughts? Best to put it back out on the street?

Seems a shame to put it out on the curb when the expensive part is still
good (the compressor). How many wires to the motor?

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[William R. Walsh]

Hi!

Seems a shame to put it out on the curb when the expensive part is still
good (the compressor). How many wires to the motor?

That's what I thought and that's why I'm reluctant to do it. It's a 1989
model and cools like brand new as long as the fan will stay running.

It is a three speed fan and if memory serves there are four wires going to
it.

William

 

[jakdedert]

William R. Walsh wrote:

Hi!

Seems a shame to put it out on the curb when the expensive part is
still good (the compressor). How many wires to the motor?

That's what I thought and that's why I'm reluctant to do it. It's a
1989 model and cools like brand new as long as the fan will stay
running.

It is a three speed fan and if memory serves there are four wires
going to it.

That makes sense...common, plus one wire for each speed. Does it exhibit

the same symptoms on every speed? Perhaps it might run reliably on the
highest speed? If so, then I'd run it that way (attended, of course) for a
while and see....

If not, a new fan 'might' be cheaper than an entire unit...you never know
these days, though. OTOH, perhaps a motor shop--if any in your vicinity,
there are in mine--might be able to help.

jak

> William

 

[William R. Walsh]

Hi!

That makes sense...common, plus one wire for each speed. Does it exhibit
the same symptoms on every speed?

Yes, the symptoms are present on every speed. The only difference
(logically) is that the slower speeds become "gummed up" much more quickly
than high speed.

Perhaps it might run reliably on the
highest speed? If so, then I'd run it that way (attended, of course) for
a
while and see....

I had high hopes for this. It will run at least, but not always 20 minutes
before slowing up and finally stopping with a hum from the motor.

As mentioned, the motor starts right up with a flick of my hand and acts
like nothing ever happened at all. However, power cycling the fan will not
fix the problem unless it is off for a really long while.

If not, a new fan 'might' be cheaper than an entire unit...you never know
these days, though. OTOH, perhaps a motor shop--if any in your vicinity,
there are in mine--might be able to help.

I found a single speed motor just a short while ago with the dual shafts...I
didn't even know I had it. The shafts seem about the same as the original
motor, but maybe they are a little smaller. The RPMs are within 100 of the
original motor on high speed, so maybe I'll just rig it up that way and
enjoy the unit until it dies of some other fault. I don't really need the
lower speeds that much.

More than anything else I'd love to know what the motor's problem is. I've
seen a lot of motors die with reduced power or lowered RPMs, but this is the
darndest thing...

William

 

[Ken Weitzel]

Hi...

More than anything else I'd love to know what the motor's problem is. I've
seen a lot of motors die with reduced power or lowered RPMs, but this is the
darndest thing...

William

Missed the original post; and it's rolled off, so
don't know the size of the unit. And of course
don't know your home

Anyway, just got to wondering. Big unit, 10 or 12k btu's?
Older house wiring? Even aluminum perhaps?
Possible that it's overtaxing the wiring, or even the
line cord, heating it (increasing it's resistance)
and pulling the line voltage down to a point that the
fan would rather not run?

Far fetched I know, but maybe worth asking. Better
safe than sorry

Take care.

Ken

 

[jakdedert]

Ken Weitzel wrote:

Hi...


More than anything else I'd love to know what the motor's problem
is. I've seen a lot of motors die with reduced power or lowered
RPMs, but this is the darndest thing...

William

Missed the original post; and it's rolled off, so
don't know the size of the unit. And of course
don't know your home

Anyway, just got to wondering. Big unit, 10 or 12k btu's?
Older house wiring? Even aluminum perhaps?
Possible that it's overtaxing the wiring, or even the
line cord, heating it (increasing it's resistance)
and pulling the line voltage down to a point that the
fan would rather not run?

Far fetched I know, but maybe worth asking. Better
safe than sorry

If it's not a lubrication problem, it would almost have to be a shorted or

open pole...assuming an AC induction motor. If it's got brushes, then that
would be the first place to look, but I don't think that most A/C motors fit
that description(?). I've got some ideas, but I'm sure someone here has
more experience with these than I....

jak

Take care.

Ken

 

[ED]

On Sat, 22 May 2004 04:07:52 GMT, "William R. Walsh"
<newsgroups1@idontwantjunqueemail.walshcomptech.com> wrote:

Hi!

That makes sense...common, plus one wire for each speed. Does it exhibit
the same symptoms on every speed?

Yes, the symptoms are present on every speed. The only difference
(logically) is that the slower speeds become "gummed up" much more quickly
than high speed.

Perhaps it might run reliably on the
highest speed? If so, then I'd run it that way (attended, of course) for
a
while and see....

I had high hopes for this. It will run at least, but not always 20 minutes
before slowing up and finally stopping with a hum from the motor.

As mentioned, the motor starts right up with a flick of my hand and acts
like nothing ever happened at all. However, power cycling the fan will not
fix the problem unless it is off for a really long while.

If not, a new fan 'might' be cheaper than an entire unit...you never know
these days, though. OTOH, perhaps a motor shop--if any in your vicinity,
there are in mine--might be able to help.

I found a single speed motor just a short while ago with the dual shafts...I
didn't even know I had it. The shafts seem about the same as the original
motor, but maybe they are a little smaller. The RPMs are within 100 of the
original motor on high speed, so maybe I'll just rig it up that way and
enjoy the unit until it dies of some other fault. I don't really need the
lower speeds that much.

More than anything else I'd love to know what the motor's problem is. I've
seen a lot of motors die with reduced power or lowered RPMs, but this is the
darndest thing...

William

I would check the oil capacitor that should be tied to the motor. If
it is changing value after the motor has been running the motor will
experience a loss in its ability to produce torque and slow down.

This is of couse assuming this is a L type motor.

Ed

 

[William R. Walsh]

Hi!

Missed the original post; and it's rolled off, so
don't know the size of the unit. And of course
don't know your home

8,000 BTU. I haven't installed it yet. The home has central air, but it is
not effective in all rooms. So you might say that I have a theory that
involves placing said unit in a room that is under (or not at all) cooled.

Older house wiring? Even aluminum perhaps?

Older wiring, but that's slowly changing. Even the old stuff is copper and
looks extremely good for its age. The old wiring never really had any
problems per se (every problem we've had has been on the pole and not in the
house) but things change and it is nice to have properly done grounded
outlets or more outlets, and more breathing room for large appliances to
run. I've also found a lot of improper additions to the old wiring.

William

 

[Stan]

"William R. Walsh" <newsgroups1@idontwantjunqueemail.walshcomptech.com> wrote:

}Hello all...
}
}I trashpicked an 8,000 BTU Carrier air conditioner. It seems to be in decent
}shape apart from rotted out "accordion sides" on both ends. (Does anyone
}know where to get those alone?) However, the fan motor seems to have some
}kind of a problem. It will run fine for a while and then it will start
}dragging down until it stops turning altogether. However, giving it a push
}with my hand after it has stalled will get it moving again. Obviously I
}don't think it is safe to run this unit unattended.
}
}At no point does the motor seem to have actually siezed up, so I'm at a
}loss.

Have you tried spray component cooler to see if there is a thermal
problem anywhere?

Stan.