Slowing a celing fan

[Gazz]

I have a celing fan in the bedroom, it's remote controlled with 3 speeds selected from the remote as well as the light brightness,

Unfortunately the lowest speed setting is a little too fast and chills us too much, resulting in me turning it off, then the heat hits us and it goes back on again,

As the fan slows down when turned off, at about half the lowest speed it feels ideal, a very gentle draught that would be ideal to keep us comfortable.

I've tried running the fan in both directions, but it dosent really help, we still get chilled a little too much on the lowest speed.

The remote control jobbie in the fan is just a tap changer type, working just how the pull chain fans operate, the motor has 3 windings for the 3 speeds,

I was wondering if i'd be able to add or remove some windings from the low speed coil, but i imagine that will be a lot more hassle that i imagine??

Maybe a variac, but i guess that'd be a bit bulky, i know any triac type chopper controller will result in motor hum/buzz, which we can not have as it's right above the bed,

i think you can add capacitors to adjust mains voltage? but how would i go about working out the correct capacitance and where to put them in the circuit,

or any better ideas?

[Theo Markettos]

Autotransformer? 120-0-120 transformer, connect mains across 120s, connect fan between 0 and a 120, will give it 120V. Make sure it's rated for the current (not sure what startup current might be in this case).

Not adjustable, but maybe worth a try if you have a transformer lying around with a centre primary tap? Make sure you insulate the secondary cables.

Theo

[Bob Minchin]

Experiment with series capacitors (ac rated - of course!!)

[Capitol]

As has been said, add a series capacitor rated for 240v AC use, or reduce the sze of the internal capacitor already fitted. This slow speed problem is why I prefer to use 120V US fans as they run markedly slower in operation due to the 50Hz supply. They all use shaded pole motors, so there's a lot of slip even at full speed, that's why the windings are very resistive to start with. It's quite difficult to break them.

[meow2222]

Series capacitor is the standard method.

Another option is to change the blade angles.

NT

[Jethro_uk]

Sellotape a brick to each blade ?

[meow2222]

Shortening the blades also works.

NT

[Walkie Torquay]

Don't be silly. Sellotape a cat to each blade is, of course, the correct answer.

[Davey]

Do the rotating felines give you a cat-scan?

[Graham.]

He needs a cyclic & collective.

[Brian Gaff]

I thought these fans were of the synchronous motor type and the windings are just clever phasing to create the speed you want to get. If that is the case then all changing voltage will achieve is a lower torque not a change in speed. Brian

[meow2222]

Yes, if he wants it to take off :)

NT

[Gazz]

We almost did have our own version of the cat swinging from the rotating fan a few weeks back, SWMBO had brought round one of her other cats that had been left at her parents when she moved in with me 4 years ago, he'd never seen a celing fan before and was mesmerized by it,

He'd sit on the bed under it and try to swing his head in time with the blades, then he made a jump for it, luckily it's got clear plastic blades so he got no grip on them (the centre light globe looks like a bit like that computer thingy in flight of the navigator, but in brushed stainless instead of gold... or was it only gold when flying class 1)

Anyway, cat bounced off the blades, then bounced off the bed to the floor, shook him self off and jumped back on the bed and was watching the blades go round again, at that point he was banished from the bedroom (and thankfully from the house, back to where he came from a few days later after he turned on the 2 cats already living here)

Anyway, i'll look into playing with capacitors as that seems the best solution, problem will be that this fan starts up on any speed, so wont go too slow before it stalls from what i have read (the fans that had to start on high, then be turned down could go really slow, not sure if my fan would just stall trying to start on low if i make it too slow... if so i'll start it on level 2, then turn to level 1, but i read it could stall even after started on high.

What i really want is speed 2 to be what speed 1 is now, and speed 1 to be half of what it is now, speed 3 can be left alone, as we do use it occasionally when we have been out and the fan off and windows closed, as the windows face south, so the bedroom heats up a fair bit..... nothing as much as the room above our ground floor bedroom mind, but that's due to the

1 inch thick walls of the dormer part, i rekon i could grow bananas in there some days.

[meow2222]

never known a cat do that before :)

trying to get a foot in the pecking order

In that case I'd sooner shorten or flatten the blades, slowing it even more is going to create a failure & in some cases a fire risk. Its your chance to fit artistic 4mm ply blades.

NT

[Davey]

snip

All the ceiling fans I met in the US, in 30 years there, were of the High/Medium/Low speed sequence, so that seems to be the standard. As for the need for the occasional mass air flow, we lived in one house that had a 'Whole House Fan', which sounded like Concorde, but just sucked huge volumes of cold air from downstairs and blew everything out through the rotating roof vents. Fantastic, and it only needed to be run for about ten minutes.

[Capitol]

Lower torque gives lower speed due to air resistance.

[Graham.]

You mean the Norm, not the standard ;-)

[Davey]

But...but... but.... and this Norm is still going:

[RobertL]

That might upset the balancing and make more noise.

What about simply adding a baffle to partly cover the fan?

Robert

[meow2222]

Only if you do it incompetently

NT