Resources for tiny, low power, low torque motors?

Hi all,

I'm looking for something like a tiny motor to drive the wings of my (small) scale windmill (it's going in a diorama of sorts). Since the wings are very light, it only needs a tiny amount of power and torque. It must also be very low RPM.

Does anyone know of any guides / shops / web resources in this direction? The best I seem to be able to do is high-RPM motors that are then geared down (seems like a complicated solution, not to mention expensive :()

BR Pete

Reply to
Peter Belfontain
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doesn't Tamiya make a series of rotating display bases? Pretty sure those things have a low rpm.

Craig

Reply to
Musicman59

Cell phone & pager vibrator motors are small and not terribly expensive, but they're high RPM.

How much room is there inside the windmill? You may be able to find a cheap wristwatch or clock mechanism with a second hand to give you 1 RPM. But it could be tricky figuring out how to extend the second hand's shaft and attach the windmill blades.

An easier approach would be to put the motor in the base of the diorama where there's more room. Put a large pulley on the windmill's axle, a small pulley on the motor, and a rubber band as a drive belt. If you can't find suitable pulleys, make 'em out of sheet plastic and glue onto the axles. Much easier than finding/making gears.

If necessary, you can reduce the speed even more by adding another axle with large & small pulleys. One rubber band from the motor to the axle's large pulley; another rubber band from the axle's small pulley to the windmill's larger pulley.

Reply to
Wayne C. Morris

There are some of the Euro kits which come with a small motor (usually

16 V AC as that is the current from most model railroad transformers for accessories) and a gear tower inside a box to cut down the speed to a reasonable 5-6 rpm. You could look for one of those.

Cookie Sewell

PS I have an old East German windmill with such a motor and gearbox but have never tested the motor; at the end of the day it WAS East German and not noted for quality control!

Reply to
AMPSOne

Worm drive might be worth considering, you may find a suitable s/h loco with damaged body - Noise would be a problem though and there may be chaper alternatives. Cameras have small motors in them, someone built an 'entire layout' (pinched oval around a palm tree) on a business card that used one in the loco. Beyond that you get into the seriously odd, small fan driving 'turbine' with extra 'blades' at right angles to rotation on the outside to reduce the speed (as per the devices used on some large clocks). Not terribly practical, but it would be satisfying to get it to work. For low noise a pump circulating water to a wheel, the base of which is in the receiver tank to act as a brake. It is worth considering odd ideas, they may contain the germ of a practical solution. Chap in the UK gave his semaphoe arms 'bounce' using a swinging arm with a coin on the end, this was pivoted at the bease, from where the operating wire actuated the signal arm. The long arm was set between stretched rubber bands, pull the cord to lift the arm over centre and it falls down against the rubber, giving a very convincing bounce to the signal arm. Good luck, if you work out a solution please post, I have a (30 year old) Airfix windmill awaiting such inspiration,

Regards

Mike

Reply to
Mike Smith

Yes, but they did have very cute female olympic athletes....

Craig

Reply to
Musicman59

Not the ones I remember - other than Katarina Witt most of them were hard to tell from the men!

Cookie Sewell

Reply to
AMPSOne

You have the right idea. It needs to be a geared electric motor to give you the speed you need. You don't need to build it yourself. You can buy a geared motor (cheaply). Here are some:

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Also remember that running these motors at reduced voltage will decrease their RPMs even further. If the motor is too large to fit in your windmill then place it under the model them use pulleys with a belt (rubber band?) to transfer the motion to the windmill blades.

Peteski

Reply to
Peter W.

Geared motors are the only way, no direct drive electric motor will turn slowly enough. Rubber-band drive and a couple of small-to-large pulley sets would reduce the rpm of a motor, you just need somewhere to mount it all.

Windmills have sails rather than wings, by the way :-)

Reply to
Alan Dicey

How about if he calls it a "wind turbine?" Don't turbines have blades?

Incidently, in my readings on birth of aerodynamics, I feel most historians have left out nautical architects, who in the nineteenth century were indeed starting to research the forces on sails. While most of the early technical developers of aviation were civil engineers, I suspect some of them may well have had conversations with the nautical guys.

Reply to
Don Stauffer

Oh, yes, modern wind turbines have variable-pitch blades :-)

Old-style windmills have sails, which are trimmed for adjustment, or can be reefed. Automatic sails include Hooper's roller reefing sails and Cubitt's patent sails: almost all the terminology is the same as that used for sailing ships.

Reply to
Alan Dicey

Sails ? as in Old World / Dutch windmills? I'd pictured the type seen in Westerns (with small vanes) or even paddle-style blades.

In any event, Edmund Scientifics / scientificsonline have a couple of things that might be of interest:

Planetary Gearbox Box Set (16:1 to 400:1), Tamiya America see:

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(~$23 US / approx 3.5 rpm at 400:1)

or perhaps

4 rpm / 3 volt motor:

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(~$20 US)

Reply to
OldSchool

One more possibility. A magnet coupling(?) Motor spins a disc with a fridge magnet. Windmill vanes attached to another fridge magnet (available for $1 for half a dozen at the Dollar Store crafts section) placed close to but not touching the disc. Depending on the separation distance the vanes may move fast or slower

Reply to
PaPa Peng

One more suggestion. In the same dollar stores are hand held battery powered propeller fans. There you have a self contained motor unit complete with battery holder and switch. Adapt to power the fridge magnet clutch for your windmill.

Another idea. Funnel the fan's air output to blow up through the windmill structure and onto the back of the windmill's vanes. Sound's neat.

Reply to
PaPa Peng

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