I am replacing the old attic fan motor with a slightly less used one
from another house. The motor is a a two speed motor, but this house
is only a one speed wiring and switch.
After installing it, using only the high speed terminal, the fan is
going in the wrong direction. I tried reversing the wires in the box
to see if that'd reverse the direction but no joy.
Does this indicate that this motor cannot reverse direction?

Joe wrote:

I am replacing the old attic fan motor with a slightly less used one
from another house. The motor is a a two speed motor, but this house
is only a one speed wiring and switch.
After installing it, using only the high speed terminal, the fan is
going in the wrong direction. I tried reversing the wires in the box
to see if that'd reverse the direction but no joy.
Does this indicate that this motor cannot reverse direction?

Hi,
Depends on what kinda motor.

"Joe" wrote:

Does this indicate that this motor cannot reverse direction?

In the dusty recesses of my mind, I seem to recall that electric motors are
wound to run CW or CCW. My guess would be no, you can't.

However, have you considered flipping the fan blade over?

On Mon, 09 Apr 2007 19:55:18 -0600, Rick Blaine
wrote:

"Joe" wrote:

Does this indicate that this motor cannot reverse direction?

In the dusty recesses of my mind, I seem to recall that electric motors are
wound to run CW or CCW. My guess would be no, you can't.

There are reversible fan motors. I used to have a 21" box fan that
had one. Don't know how common they are, or in this size.

But it would have an extra wire. And there is an extra wire, but you
think that is for the other speed. If you're not positive, it
wouldn't take long to connect it instead and find out.

However, have you considered flipping the fan blade over?

Strangely, that wouldn't change anything, but turning the whole motor
over would. Would it be safe to run that way? You'd probably have to
build a bigger shield and screen.

On 9 Apr 2007 18:39:28 -0700, "Joe" wrote:

I am replacing the old attic fan motor with a slightly less used one
from another house. The motor is a a two speed motor, but this house
is only a one speed wiring and switch.
After installing it, using only the high speed terminal, the fan is
going in the wrong direction. I tried reversing the wires in the box
to see if that'd reverse the direction but no joy.
Does this indicate that this motor cannot reverse direction?

Most motors can NOT be reversed.

deke wrote:

Most motors can NOT be reversed.

I would qualify that. I think if they are designed to run in reverse, they will
have separate windings for each direction, with only one of the windings
energized at a time.

"Joe" wrote in message
oups.com...
I am replacing the old attic fan motor with a slightly less used one
from another house. The motor is a a two speed motor, but this house
is only a one speed wiring and switch.
After installing it, using only the high speed terminal, the fan is
going in the wrong direction. I tried reversing the wires in the box
to see if that'd reverse the direction but no joy.
Does this indicate that this motor cannot reverse direction?

Could be. Is the wiring inside a box with a plate on it? Some have wiring
diagrams inside, some have a plate on the motor. Some have none and cannot
be reversed. Check the manufacturer web site also.

On Apr 10, 10:04 am, Rick Blaine wrote:
deke wrote:
Most motors can NOT be reversed.

I would qualify that. I think if they are designed to run in reverse, they will
have separate windings for each direction, with only one of the windings
energized at a time.

Vague memories... if it has no windings in the rotor, as many don't,
it just runs on phase lag and hysterisis or some such and is
unidirectional. If there are windings in the stator and the rotor,
then presumably they can be flipped relative to each other... don't
know how relevant each type is to the size of motor that might be in a
house fan.

In article .com,

z wrote:

On Apr 10, 10:04 am, Rick Blaine wrote:
deke wrote:
Most motors can NOT be reversed.

I would qualify that. I think if they are designed to run in reverse,
they will
have separate windings for each direction, with only one of the windings
energized at a time.

Vague memories... if it has no windings in the rotor, as many don't,
it just runs on phase lag and hysterisis or some such and is
unidirectional. If there are windings in the stator and the rotor,
then presumably they can be flipped relative to each other... don't
know how relevant each type is to the size of motor that might be in a
house fan.


Reversible induction motors will generally have a data plate with
wiring connections diagrammed to show how to reverse direction. If it
is a shaded-pole motor or other design that is not electrically reversible,
it is sometimes possible to dissassemble the motor, turn the stator
180 degrees, and reassemble to reverse the direction. OTOH, if the
attic access and the fan are anything like the one in my house,
I'd probably just pony up the $60 or $80 for a whole new fan assembly
and be sure it would work for a while, I just don't enjoy working in a
crouched position standing on top of a square of plywood layed over the
ceiling joists in a space full of blown-in cellulose insulation, dust, and
low light.



--
There are no stupid questions, but there are lots of stupid answers.

Larry Wasserman - Baltimore Maryland - lwasserm(a)sdf. lonestar. org

On 9 Apr 2007 18:39:28 -0700, "Joe" wrote:

I am replacing the old attic fan motor with a slightly less used one
from another house. The motor is a a two speed motor, but this house
is only a one speed wiring and switch.
After installing it, using only the high speed terminal, the fan is
going in the wrong direction. I tried reversing the wires in the box
to see if that'd reverse the direction but no joy.
Does this indicate that this motor cannot reverse direction?

Is there a belt you can cross?

tom @ www.Consolidated-Loans.info

On 2007-04-10, Joe wrote:
I am replacing the old attic fan motor with a slightly less used one
from another house. The motor is a a two speed motor, but this house
is only a one speed wiring and switch.
After installing it, using only the high speed terminal, the fan is
going in the wrong direction. I tried reversing the wires in the box
to see if that'd reverse the direction but no joy.
Does this indicate that this motor cannot reverse direction?

Is there any way you could instead change the pitch of the blades, so
that the air goes in the direction you want with the fan rotating in the
current direction?

"Just Joshin" wrote in message
...
On 9 Apr 2007 18:39:28 -0700, "Joe" wrote:

I am replacing the old attic fan motor with a slightly less used one
from another house. The motor is a a two speed motor, but this house
is only a one speed wiring and switch.
After installing it, using only the high speed terminal, the fan is
going in the wrong direction. I tried reversing the wires in the box
to see if that'd reverse the direction but no joy.
Does this indicate that this motor cannot reverse direction?

Is there a belt you can cross?

tom @ www.Consolidated-Loans.info

Sure you aren't using the wrong pitch blade from the old fan with the 'new'
motor?

On 4/9/2007 8:39 PM, Joe wrote:
I am replacing the old attic fan motor with a slightly less used one
from another house. The motor is a a two speed motor, but this house
is only a one speed wiring and switch.
After installing it, using only the high speed terminal, the fan is
going in the wrong direction. I tried reversing the wires in the box
to see if that'd reverse the direction but no joy.
Does this indicate that this motor cannot reverse direction?

If it has a capacitor to start/run then yes it can be reversed. But you
have to know what you are doing. Find an electrician/AC friend to do it
for you, or take the motor to a rebuilding service. They should do it
for a coupla bucks. It only involves moving a spade lug over.

--
Ted
I wasn't born in Texas but
I got back here as soon as I could
(Don't forget to take out the trash)

If you never try anything new, you'll miss out on many of life's great
disappointments.