Slowing down a fan?

[Dave, I can't do that]

Hi, we have a 3-speed 12" desk-style fan for the dog and on the low speed it is still too fast and the dog ends up shivering. Without it he gets uncomfortably warm so I would like to slow it down. He likes sleeping where he likes sleeping, so we have to make where he wants to be how we think it needs to be. :)

I took the cover off and it has a 3.5u 250v cap, a three position switch with a worm-drive gearbox for oscillation which we don't need.

Is there some form of fan speed controller I can buy off the shelf that I can wire into this? It does not have to be a plug in thing as I can wire it into the wall outlet where the fan is plugged in.

Thanks

Dave and dog

[Jim Thompson]

We have sweaters for our Dachshunds. They hate cold so much they'll
go out and lay on the deck in the sun when it's 110°F outside ;-)

I'm sort of like that myself.

...Jim Thompson
--
| James E.Thompson | mens |
| Analog Innovations | et |
| Analog/Mixed-Signal ASIC's and Discrete Systems | manus |
| San Tan Valley, AZ 85142 Skype: skypeanalog | |
| Voice:(480)460-2350 Fax: Available upon request | Brass Rat |
| E-mail Icon at http://www.analog-innovations.com | 1962 |

I love to cook with wine. Sometimes I even put it in the food.

[rickman]

Isn't the easy way to have the fan blow indirectly to the dog? Or just
put a book or something in front of the fan to block part of the air
flow? Even just moving the fan back further will quickly reduce the air
flow around the dog.

--

Rick

[tabb...@gmail.com]

Don't. The reason these fans don't go slower is that the risk of stalling & catching fire gets too great. Move it further away or use a slow speed low power ceiling fan, eg a 6 watter.


NT

[Phil Hobbs]

+1. Aim it at the ceiling.

Cheers

Phil Hobbs

--
Dr Philip C D Hobbs
Principal Consultant
ElectroOptical Innovations LLC
Optics, Electro-optics, Photonics, Analog Electronics

160 North State Road #203
Briarcliff Manor NY 10510

hobbs at electrooptical dot net
http://electrooptical.net

[Neon John]

On Sat, 4 Jul 2015 10:22:58 -0700 (PDT), "Dave, I can't do that"
<dave...@gmail.com> wrote:


>Is there some form of fan speed controller I can buy off the shelf that I can wire into this? It does not have to be a plug in thing as I can wire it into the wall outlet where the fan is plugged in.

Yes. Being a capacitor run motor, it should respond well to an
inductance-rated phase angle controller. The most common is the
ceiling fan speed control sold at Lowe's, etc.

If the motor is the type that stalls on undervoltage, you're out of
luck. I've never seen a capacitor-run motor that would but there's
always a first.

Even if the fan stalls, it will not cause a fire. Small motors like
those are either impedance protected and/or equipped with a thermal
fuse.

I have a large version of this in my house. I wanted a whole house
ceiling fan but I did not want the noise of a propeller-type so I got
a large 1HP squirrel cage blower from an old central AC and built a
box around it so that it would suck through the louvers I installed in
the ceiling and exhaust into the attic.

I control it with a Lutron 1kW inductance rated commercial lamp
dimmer, available at Home Depot (but not anywhere else, at least in
this area).

I took the stator out of the motor, took it down to the electric motor
repair shop where I sometimes moonlight and dipped it in the varnish
tank and baked it out. This cemented the windings in the slots and
coated the stator iron with sound damping varnish to diminish the
magnetrostriction noise. The motor is now essentially silent even
when running at low phase angles.

The fan is gross overkill on full speed, causing the curtains to
billow out away from the windows all over the house. I designed it
that way so I could run the fan normally at reduced speed which is
again essentially silent.

A fan is a square law device, speed vs flow, so just a small reduction
in speed results in a large reduction in airflow and power draw. The
motor will not overheat.

The type of motor in my fan is called an "air-over cooled" motor. That
is, it is cooled by the air flowing over it. Initially I was a bit
concerned about the reduced cooling flow and of the increased eddy
currents induced in the stator iron by the phase angle control.

So I glued a thermocouple to the winding and monitored the temperature
for awhile. The motor actually ran cooler at reduced speed because
the current demand is so dramatically reduced by the speed reduction.

In summary, all you need is a ceiling fan speed control unit and some
method to splice it into the power cord of the fan. The speed control
normally comes with flying leads so wire nuts and electrical tape will
do the trick.

John

John DeArmond
http://www.neon-john.com
http://www.fluxeon.com
Tellico Plains, Occupied TN
See website for email address

[bloggs.fred...@gmail.com]

Just put one of these on a milk crate or something...sheesh:

http://www.amazon.com/Adjustable-Shutter-Damper-Ceiling-Register/dp/B00BE7TO0A

[DecadentLinuxUserNumeroUno]

On Sun, 5 Jul 2015 08:28:27 -0700 (PDT),
bloggs.fred...@gmail.com Gave us:

snipped overtly long lines as web access folks still don't get that
Usenet is a TEXT forum.

>> Dave and dog
>
>Just put one of these on a milk crate or something...sheesh:
>
>http://www.amazon.com/Adjustable-Shutter-Damper-Ceiling-Register/dp/B00BE7TO0A

Go smaller. Dogs don't need that much...

http://www.amazon.com/Thermaltake-Mobile-External-Cooling-AF0007/dp/B002OJN250

[Syd Rumpo]

Wire a light bulb socket in series and select a suitable mains filament
bulb to limit the current. The motor won't burn out or stall, but you
could always check this by experiment if you're nervous.

I did this years ago for a ceiling fan which was a bit
over-enthusiastic. Two bulbs were used depending on the speed wanted -
IIRC a 40W bulb and a 100W bulb.


Cheers
--
Syd

[Syd Rumpo]

On 05/07/2015 17:37, Syd Rumpo wrote:

<snip>

>
> Wire a light bulb socket in series and select a suitable mains filament
> bulb to limit the current.

Reduce the current, not really limit. Sloppy.

Cheers
--
Syd

[Techman]

4 bladed fan? Lop off two blades?

[DecadentLinuxUserNumeroUno]

On Mon, 06 Jul 2015 15:11:31 +0800, Techman <junk...@bogus.com> Gave
us:

>4 bladed fan? Lop off two blades?

Blade lopping. Not heard that one in decades. Yeah... that's
intelligent.

[Techman]

Educate me - what would cause problems? Only thing I can think of is
that it may run faster.

[DecadentLinuxUserNumeroUno]

On Tue, 07 Jul 2015 16:58:52 +0800, Techman <junk...@bogus.com> Gave

us:

>On 06-Jul-15 8:26 PM, DecadentLinuxUserNumeroUno wrote:
>> On Mon, 06 Jul 2015 15:11:31 +0800, Techman <junk...@bogus.com> Gave
>> us:
>>
>>> 4 bladed fan? Lop off two blades?
>>
>> Blade lopping. Not heard that one in decades. Yeah... that's
>> intelligent.
>>
>
>
>Educate me

Simple. Read the title of the original post. Ooops!

> - what would cause problems?

It would not accomplish what the OP asked for.

> Only thing I can think of is
>that it may run faster.

Lopping off sentence structure as well, eh?

It *will* run faster, and be more wasteful than actually slowing it
down, which is what was asked for.

Not as bad as the "light bulbs in series" "solutions" that were
suggested though.

[Techman]

Sure it may run faster but it may also push less air, which is what was
asked for.

I'm not sure it would be more wasteful. Wasteful of what? Energy? I
imagine it would be doing less work and use less energy than the
original blade.


Imagine a 2 bladed fan factory where the marketing blokes ask for a same
sized fan with higher through-put. I reckon one of the first suggestions
from engineering would be to put two more blades on it and up the motor
power......


Anyway YMMV. ;)

[Martin Brown]

On 05/07/2015 02:31, Neon John wrote:
> On Sat, 4 Jul 2015 10:22:58 -0700 (PDT), "Dave, I can't do that"
> <dave...@gmail.com> wrote:
>
>
>> Is there some form of fan speed controller I can buy off the shelf that
>> I can wire into this? It does not have to be a plug in thing as I
can wire
>> it into the wall outlet where the fan is plugged in.
>
> Yes. Being a capacitor run motor, it should respond well to an
> inductance-rated phase angle controller. The most common is the
> ceiling fan speed control sold at Lowe's, etc.
>
> If the motor is the type that stalls on undervoltage, you're out of
> luck. I've never seen a capacitor-run motor that would but there's
> always a first.
>
> Even if the fan stalls, it will not cause a fire. Small motors like
> those are either impedance protected and/or equipped with a thermal
> fuse.

I have a similar problem related to the slowest setting on my office fan
being too fast for comfort. The problem is that although the breeze it
produces is pleasant enough for me it isn't good for all the documents I
have lying around and they get blown around the room.

Its practical settings are pretty much along the lines of hurricane,
severe gale or gale although they are labelled high, medium and low.

I have been wondering about putting a phase angle controller in front of
it but have resisted the temptation so far. Only actually had one day
this summer so far where it has been needed.

--
Regards,
Martin Brown

[DecadentLinuxUserNumeroUno]

On Tue, 07 Jul 2015 18:55:07 +0800, Techman <junk...@bogus.com> Gave
us:

>I'm not sure it would be more wasteful. Wasteful of what? Energy? I
>imagine it would be doing less work and use less energy than the
>original blade.

Depends on the type of motor.

Frequency dependent type would remain at the same rpm if not a slight
bit higher due to less loading.

The other type would spin faster and may even end up feeding the same
air mass rate.

What he asked for was a manner in which to SLOW down his fan with a
result of less air moving.

Lopping off half the blades is not a good choice to arrive at that
result.

So, YM(aeo)DV. "Your Mileage (and education obviously) DOES Vary".

[DecadentLinuxUserNumeroUno]

On Tue, 07 Jul 2015 12:13:53 +0100, Martin Brown
<|||newspam|||@nezumi.demon.co.uk> Gave us:

Get one of the USB driven "Thermaltake" jobs I previously posted a
link to. They are fully speed controlled.

[rickman]

Sounds like a great application for a three way bulb. Then you could
get three settings.

--

Rick

[Techman]

Interesting how "depends" and "may" have now crept in. :)

[Syd Rumpo]

Four - you could have a series combination too!

I wasn't sure if the three way bulb was a joke I didn't understand, so I
Googled it. I've never heard of such a thing, although some car bulbs
are similar - can you still get them? Is it just a US thing?

Cheers
--
Syd

[Paul Hovnanian P.E.]

My desk fan is an old 5" PC power supply hooked to a variable power supply.
I just set it where I want it.


--
Paul Hovnanian mailto:Pa...@Hovnanian.com
------------------------------------------------------------------
A noble spirit embiggens the smallest man.

[jurb...@gmail.com]

>" did this years ago for a ceiling fan which was a bit
>over-enthusiastic. Two bulbs were used depending on the speed wanted -
>IIRC a 40W bulb and a 100W bulb. "

Unacceptable. This is sci.electronics.DESIGN. that means we are in search of the absolute most ocmplex solution ossible.

Therefore I think we should come up wwith a deal with osme flip flops to only sens every other cycle to the motor via triacs making it effectively 30 Hz. Of course then we need to lose a little bit of voltage, or am I wrong on that ?

If we just used a variable frequency control I am pretty suie the lower frequency, because of the inductance would require a lower voltage. But if we just hillilly it and let the pulses be 1/60th of of a second at 30 Hz it might not be a problem at all. Err, that would be 1/120th of a second though, right ?

[krw]

>If we just used a variable frequency control I am pretty suie the lower frequency, because of the inductance would require a lower voltage. But if we just hillilly it and let the pulses be 1/60th of of a second at 30 Hz it might not be a problem at all. Err, that would be 1/120th of a second though, right ? \

Just use a PIC.

[Phil Hobbs]

>Just use a PIC.

Sure, wire it in series with the mains to drop the voltage. ;)

Cheers

Phil Hobbs

[rickman]

I dunno. The lamps that use 3 way bulbs are quite common in the US. It
is a bit of a PITA too. The default wiring of the 3 way socket could
have been made to operate compatibly with a standard bulb, was instead
wired so you have to click the switch twice to turn a standard bulb on
or off. As such it is very common to run into this inconvenient
combination.

I don't expect to ever see a 3 way CFL bulb, but I don't get why no one
makes a compatible LED bulb. There are literally millions of 3 way
lamps out there that no one is going to rewire. Instead they will
forever be inconvenient to use.

--

Rick

[rickman]

lol

--

Rick

[jurb...@gmail.com]

>"The default wiring of the 3 way socket could
>have been made to operate compatibly with a standard bulb, was instead
>wired so you have to click the switch twice to turn a standard bulb on
>or off. As such it is very common to run into this inconvenient
>combination. "

Doing so could have caused an insidious shock hazard because with a standard bulb in a three way socket, in every other "off" position there would still be a hot terminal in the socket.

[rickman]

I don't follow. Why is an unconnected terminal in the socket a
dangerous condition? You can't reach it when a bulb is plugged in.
When no bulb is plugged in there are two "shock" hazards.

The current design has exactly the same issue in any case.

--

Rick

[krw]

How so? If you reverse the contacts, there is still one (single
filament light bulb) "off" position with a hot contact.

[krw]

I have a "3-way" CLF fixture in a ceiling fan. Its switch wired for
off-one-three-four 60W equivalent CFLs. ;-)

[krw]

On Fri, 10 Jul 2015 04:57:31 -0700 (PDT), Phil Hobbs
<pcdh...@gmail.com> wrote:

>>Just use a PIC.
>
>Sure, wire it in series with the mains to drop the voltage. ;)
>

It will.

[jurb...@gmail.com]

>"The current design has exactly the same issue in any case. "

With a regular bulb in a three way socket, it is OFF-OFF-ON-ON. After the second "ON" the next click is all off. You know it is off. so if you had used a regular bulb in a pinch and then obtain a three way bulb and go to install it, you KNOW it is off after that last "ON" position.

The other possibility might sound like a conspiracy theory. That three way lamp manufacturers were in cahootz with the three way bulb manufacturers and wantd to inconvenince those who did not pay up for the three way bulbs.

I also find it very suspicious that the gasoline "they" make works perfectly in the cars "they" sell. And did you notice about cassettes way back then ? Ever hear the axion "Create a need and fill it" ?

Obviously a big plot to make money.

The car thing, Ransom Eli Olds started that in this country. Before then they used to burn gasoline out in the fields beecauseit was considered a waste product. Stunk, no good for cooking nor lamps, and in fact amost dangerous to keep in the house. So up comes the first conspirator and figures out how to use the shit. the rest is history and now the waste product they used to just burn to get rid of, is now the lifeblood of society to the point where we fight wars over it.

The plan obviously worked.

</sarcasm and satire>