# Run multiple motors off a single power source? & Slow them down?

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#### Skara

##### New Member
I'm in the process of starting a sculpture project that I plan to have move around a bit by having parts of it slowly rotate.

#### gerty

##### Member
A friend just finished a project ussing a motor from from a barbeque grill. It turned at the proper speed (gear reduction) and was rated continous duty.

#### Skara

##### New Member
Hm. yeah, I've got a little hobby motor, but it turns so fast I don't see how I could ever get it slow enough.

I do have a lathe; what materials are appropriate for a pulley? Could I use scrap wood or should I go with a heavy plastic?
Also, do you have any tips for making a belt?

#### things

##### New Member
Just grab a worm gear and mount it on a motor, they are very slow, but at a fair bit of torque

#### jpanhalt

##### Well-Known Member
Worm gears work great for slow speed and they effectively are auto-braking. That is, it is extremely hard (if at all possible) to turn the motor by turning the output shaft. On the downside, layout is more critical than with spur gears and they impart a 90° shift.

A pre-made gear motor, such as the BBQ grill would still be my first choice for slow speed and quiet operation. The planetary gear ones are probably the most quiet and slowest. Cheap, import winches (like at Harbor Freight) are another source of planetary drives and have very slow outputs. Old clockworks (many suppliers on the Internet) will give you three choices of speed (1 rpm, 1 rph, and 1 or 2 rpd.

If you want to go with pulleys/sheaves to get a second stage of speed reduction, these sources may be helpful:

http://www.mcmaster.com/
http://sdp-si.com/catalogs.htm

Check under the term "sheaves" as well as pulley. Some places are particular about that term, others are not.

John

Edit: Forgot the question about materials. Delrin (acetal) is a great plastic for such purposes. Round belts are easy to work with and quiet. The sheaves/pulleys are a little harder to machine for them though.

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#### grim

##### New Member
for something fairly light duty like this, have you considered Lego?

not the toy stuff, but the grown up engineering experimentation and development system (ok, it's still a toy really)

motors, gears, everything you need, and it all fits together with no tools.

#### Hank Fletcher

##### New Member
Hm. yeah, I've got a little hobby motor, but it turns so fast I don't see how I could ever get it slow enough.

I do have a lathe; what materials are appropriate for a pulley? Could I use scrap wood or should I go with a heavy plastic?
Also, do you have any tips for making a belt?
Cheap, surplus gearmotors are the way for you to go, but they still might be slightly too fast for what you want. Oooo... you have a lathe?! Scrap wood can make for some nice pulleys. If you ever want to pay to class it up, aluminum can make some really nice pulleys (but expensive!).

Elastic bands (thick, wide ones) make good belts. Larger belts can be made from surgical tubing. Shoelaces and even just good old cord works, too. Whatever you use, you want to make it stretch just a bit to get it over the groove in your pulleys. Make sure it doesn't have to stretch so much that there's undue stress put on the motors' shafts, though (for instance, when using surgical tubing).

#### Hank Fletcher

##### New Member
Here's a nice gearmotor - looks like a good deal, too:
http://www.goldmine-elec-products.com/prodinfo.asp?number=G14607

The same site has a selection of gearmotors to choose from:
http://www.goldmine-elec-products.com/products.asp?dept=1300

as well as a wider selection of various electric motors:
http://www.goldmine-elec-products.com/departments.asp?dept=1103

What's your plan for powering your motors? You could use a car battery, but if you want to run them from a wall outlet, I suggest using a modified computer power supply (easy noob project).

#### Skara

##### New Member
Hank Fletcher said:
Cheap, surplus gearmotors are the way for you to go, but they still might be slightly too fast for what you want. Oooo... you have a lathe?! Scrap wood can make for some nice pulleys. If you ever want to pay to class it up, aluminum can make some really nice pulleys (but expensive!).

Elastic bands (thick, wide ones) make good belts. Larger belts can be made from surgical tubing. Shoelaces and even just good old cord works, too. Whatever you use, you want to make it stretch just a bit to get it over the groove in your pulleys. Make sure it doesn't have to stretch so much that there's undue stress put on the motors' shafts, though (for instance, when using surgical tubing).

...

...if you want to run them from a wall outlet, I suggest using a modified computer power supply (easy noob project).
I actually have some scrap aluminum too... ^_^

I guess I was thinking a belt needed to be..mm..closer to perfection than a shoelace. I guess I was overthinking it.

Didn't think of using a computer power supply. I have a couple of those laying around too. ^_^;;

Wow, these are great ideas. I'm actually seriously thinking about the clockwork motors now too. I think having 24hr, 1hr, and 1min sections would be cool. I could still incorporate oddly moving bits too.

Thanks everyone for all the great help and ideas!!

Oh, but one more note about powering them... How can I give them the right power? I think hooking a 9V motor straight into the wall might not be a good idea, so how does a power supply regulate this? Is there another part I need or can I figure out what the power supply does...? (????)

grim said:
for something fairly light duty like this, have you considered Lego?
o.o I used to love legos when I was a kid. I think I might have some of my old legos in storage. I think I had some kind of train than that had a motor, too. Even if it doesn't work well for all of it, it may be good for testing purposed and such like that. Nice idea.

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