Slowing down a fan?

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

I took the cover off and it has a 3.5u 250v cap, a three position switch wi th 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 c an 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

Reply to
Dave, I can't do that
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We have sweaters for our Dachshunds. They hate cold so much they'll

I'm sort of like that myself. ...Jim Thompson

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| James E.Thompson                                 |    mens     | 
| Analog Innovations                               |     et      | 
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Jim Thompson

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.

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Rick
Reply to
rickman

it is still too fast and the dog ends up shivering. Without it he gets unc omfortably 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 ne eds to be. :)

with a worm-drive gearbox for oscillation which we don't need.

can wire into this? It does not have to be a plug in thing as I can wire i t into the wall outlet where the fan is plugged in.

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

Reply to
tabbypurr

+1. Aim it at the ceiling.

Cheers

Phil Hobbs

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Dr Philip C D Hobbs 
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Reply to
Phil Hobbs

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

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Syd
Reply to
Syd Rumpo

Reduce the current, not really limit. Sloppy.

Cheers

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Syd
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Syd Rumpo

4 bladed fan? Lop off two blades?
Reply to
Techman

On Mon, 06 Jul 2015 15:11:31 +0800, Techman Gave us:

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

Reply to
DecadentLinuxUserNumeroUno

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

Reply to
Techman

On Tue, 07 Jul 2015 16:58:52 +0800, Techman Gave us:

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

It would not accomplish what the OP asked for.

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.

Reply to
DecadentLinuxUserNumeroUno

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. ;)

Reply to
Techman

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.

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Regards, 
Martin Brown
Reply to
Martin Brown

On Tue, 07 Jul 2015 18:55:07 +0800, Techman Gave us:

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".

Reply to
DecadentLinuxUserNumeroUno

On Tue, 07 Jul 2015 12:13:53 +0100, Martin Brown Gave us:

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

Reply to
DecadentLinuxUserNumeroUno

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

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Rick
Reply to
rickman

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

Reply to
Techman

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

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Syd
Reply to
Syd Rumpo

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

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Paul Hovnanian     mailto:Paul@Hovnanian.com 
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Paul Hovnanian P.E.

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

Therefore I think we should come up wwith a deal with osme flip flops to on ly 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 o n that ?

If we just used a variable frequency control I am pretty suie the lower fre quency, 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 mi ght not be a problem at all. Err, that would be 1/120th of a second though, right ?

Reply to
jurb6006

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