I needed a new motor for my roof fan, ordered it on Thursday, and
picked it up 40 miles from here on the same day. Friday, I went to the
motor store in town to retrieve the old motor.

Same model number, on the box and on the name plate. I compared them
and they seemed the same.

Installed the new one this morning at 9. Attic a little warm, but with
my shirt off, not uncomfortable.

Always tricky but harder than I remember to get the blade and the motor
past the 3 brackets, even though they are disconnected from each other
and dangling. I wish I could put the blade on after putting the blade
and motor in place separately, but that would not work. Not a lot
of clearance. Motor has to be vertical, and if the blade were higher,
would hit the cover of the fan. Which says Nautilus on it, btw. I
pushed it and not brittle yet, afaict.

Get all three brackets bolted to each other, two of them tightened down,
but the third is tight already and still 3/8" between the two brackets.

That's when it dawns on me that the new one has a layer of smooth black
plastic around the top 3rd. Maybe 2 or 3/32th" thick. (The motor is
about 3" high and 5.5" in diameter.)

Get out of the attic and check the old motor. No, it doesn't have that
plastic. I wonder how hard it woudl have been to rip it off.

And now I wonder how long the bracket will hold with no lock washer
(does that matter in this case?) and the two pieces of sheet metal not
touching.

I'll call the fan company asaic.

micky wrote:
I needed a new motor for my roof fan, ordered it on Thursday, and
picked it up 40 miles from here on the same day. Friday, I went to the
motor store in town to retrieve the old motor.

Same model number, on the box and on the name plate. I compared them
and they seemed the same.

Installed the new one this morning at 9. Attic a little warm, but with
my shirt off, not uncomfortable.

Always tricky but harder than I remember to get the blade and the motor
past the 3 brackets, even though they are disconnected from each other
and dangling. I wish I could put the blade on after putting the blade
and motor in place separately, but that would not work. Not a lot
of clearance. Motor has to be vertical, and if the blade were higher,
would hit the cover of the fan. Which says Nautilus on it, btw. I
pushed it and not brittle yet, afaict.

Get all three brackets bolted to each other, two of them tightened down,
but the third is tight already and still 3/8" between the two brackets.

That's when it dawns on me that the new one has a layer of smooth black
plastic around the top 3rd. Maybe 2 or 3/32th" thick. (The motor is
about 3" high and 5.5" in diameter.)

Get out of the attic and check the old motor. No, it doesn't have that
plastic. I wonder how hard it woudl have been to rip it off.

And now I wonder how long the bracket will hold with no lock washer
(does that matter in this case?) and the two pieces of sheet metal not
touching.

I'll call the fan company asaic.

LOL, you are getting younger. The older you are, the wiser you get.

On Sat, 16 May 2015 17:45:16 -0600, Tony Hwang wrote:

micky wrote:
I needed a new motor for my roof fan, ordered it on Thursday, and
picked it up 40 miles from here on the same day. Friday, I went to the
motor store in town to retrieve the old motor.

Same model number, on the box and on the name plate. I compared them
and they seemed the same.

Installed the new one this morning at 9. Attic a little warm, but with
my shirt off, not uncomfortable.

Always tricky but harder than I remember to get the blade and the motor
past the 3 brackets, even though they are disconnected from each other
and dangling. I wish I could put the blade on after putting the blade
and motor in place separately, but that would not work. Not a lot
of clearance. Motor has to be vertical, and if the blade were higher,
would hit the cover of the fan. Which says Nautilus on it, btw. I
pushed it and not brittle yet, afaict.

Get all three brackets bolted to each other, two of them tightened down,
but the third is tight already and still 3/8" between the two brackets.

That's when it dawns on me that the new one has a layer of smooth black
plastic around the top 3rd. Maybe 2 or 3/32th" thick. (The motor is
about 3" high and 5.5" in diameter.)

Get out of the attic and check the old motor. No, it doesn't have that
plastic. I wonder how hard it woudl have been to rip it off.

And now I wonder how long the bracket will hold with no lock washer
(does that matter in this case?) and the two pieces of sheet metal not
touching.

I'll call the fan company asaic.

LOL, you are getting younger.

Well that's good.

The older you are, the wiser you get.

Thanks for showing me the bright side of this

On Sat, 16 May 2015 18:40:27 -0400, micky
wrote in

Always tricky but harder than I remember to get the blade and the motor
past the 3 brackets, even though they are disconnected from each other
and dangling.

So you've done this replacement at least once before?
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On Sun, 17 May 2015 06:04:49 -0500, CRNG
wrote:

On Sat, 16 May 2015 18:40:27 -0400, micky
wrote in

Always tricky but harder than I remember to get the blade and the motor
past the 3 brackets, even though they are disconnected from each other
and dangling.

So you've done this replacement at least once before?

Probably 4 or at least 3 times in the last 22 years (starting when the
fan was 10 years old.) .

This is the first time the motor wasn't an exact match. The plastic
layer looked like it would be very hard to get off, but I would have
done it if it had only dawned on me that it cause the brackets not to
fit right.

The motor also has 3 screws sticking out the back (that hold the thing
together) and 4 sticking out the front (that have no other purpose) for
mounting, so maybe they've forgotten that some mount the way mine does.

Except at www.emotorstore.com the motor is listed under Fasco and then
under the category of "Roof Top Ventilator", and although it could be
done another way, I'd bet most such fans mount the motor like mine. I
still plan to call them when I get back from out of town, and it would
be great if I found someone who actually knows why the plastic was added
and if they considered people like me when they did so. They should
have put a suffix on the model number and a note in the specs

http://www.emotorstore.com/productde..._skuID_E_25695

Another interesting thing is that the flat spot on the shaft, that the
set screw tightens into, runs for almost 3 inches. I thought that might
be enough to unbalance the motor. Do they make some other provision to
make up for the shaft not being symmetric?

On 5/17/15 8:25 AM, micky wrote:

Another interesting thing is that the flat spot on the shaft, that
the set screw tightens into, runs for almost 3 inches. I thought
that might be enough to unbalance the motor. Do they make some other
provision to make up for the shaft not being symmetric?


Is it a 3/8" shaft? On a 1050 RPM motor, centrifugal force on the
circumference of the shaft would be about equal to gravity. If it were a
gram out of balance, that would be .001 newton.

If you'd popped the dome off, you would have had room to work. You
should have left it off. An efficient fan works by imparting motion, not
pressure. If a dome blocks the way, right above the blades, it turns the
motion into pressure for the fan to fight.

What you need is an an electrical umbrella and a DPDT thermostat. An
electrical umbrella will protect your vent from rain and snow. When the
thermostat turns on the fan, the umbrella will collapse, leaving your
fan free to do its job and not wear out the motor.

I happen to sell electrical umbrellas on ebay, but I don't want you to
think this is a sales pitch. Check the electrical goods department at
your Goodwill store. They may have one for 50% off. If you can't find
it there, get back to me. I have a hundred-unit minimum, but when others
see your electrical umbrella, you can charge what the market will bear.

On Sun, 17 May 2015 08:25:40 -0400, micky
wrote in

On Sun, 17 May 2015 06:04:49 -0500, CRNG
wrote:

On Sat, 16 May 2015 18:40:27 -0400, micky
wrote in

Always tricky but harder than I remember to get the blade and the motor
past the 3 brackets, even though they are disconnected from each other
and dangling.

So you've done this replacement at least once before?

Probably 4 or at least 3 times in the last 22 years (starting when the
fan was 10 years old.) .

Maybe you should consider one of these

http://www.homedepot.com/p/Master-Fl...1?N=5yc1vZc665

I have two on my roof that have been working without a problem for 30
years.
--
Web based forums are like subscribing to 10 different newspapers
and having to visit 10 different news stands to pickup each one.
Email list-server groups and USENET are like having all of those
newspapers delivered to your door every morning.

On 5/17/15 3:17 PM, J Burns wrote:
Is it a 3/8" shaft? On a 1050 RPM motor, centrifugal force on the
circumference of the shaft would be about equal to gravity. If it were a
gram out of balance, that would be .001 newton.

Uh-oh, it's a 1/2" shaft and 8 times gravity, or .08 newton.

This has shaken my confidence. I'd better double check the design of my
electrical umbrella.