Need Help Figuring out where to buy the right motor and the right gears

[rs14smith]

For a small project, I'm building a solar tracker that will be rotated by a DC motor and two gears based on my drawing for it.

The only issue I'm having is, figuring out where can I buy 2 gears with 1.5" diameter, with a lot of teeth. My panel only weights 2.2lbs

The next issue is, finding a decent "small" DC motor that will allow the gear to be attached to the rode (the small metal cylinder part that sticks out of the motor).

I've been searching Google like a mad man but can't seem to figure out how to match the two...either the gear is too small, or the gear doesn't look like it's made for the motor I picked..etc.

Any help is appreciated thanks!

 

[cr0sh]

If I were you, I would use two servos (be sure to get metal gears and ball bearing construction - these cost more than standard servos, but will last longer); the bottom one (pan) could be what's known as a "sail winch" servo (or it could be a large 1/4 scale servo), and the "tilt" servo can be something smaller. I've heard good things about servocity.com; they have good prices, and good products, plus they sell pan/tilt units with the servos.

In the end, it is what you'll be constructing anyway, so you might as well save yourself the grief of procuring the motors, gears, and other assorted devices, then attempting to build the entire system yourself; gearboxes are anything but easy to properly build (unless this is your ultimate goal - to build a gearbox; but I don't think it is - is it?)...

If you still want or need sources for motors or gears, I can give those to you as well - but I must warn you that using servos will be a lot more inexpensive for the job (unless you are needing something really robust for 24/7/365 usage outdoors - then the costs can get really extreme).

 

[KeepItSimpleStupid]

What comes to mind is an antenna rotator. The Eagle Aspen ROTR-100, I think uses 18 V up a coax cable. It definately has a small motor inside. Designs such as these use gear reduction combined with a worm gear. The worm acts as a one way clutch or sorts.

Although expensive, linear actuators with potentiometer feedback can also be used.

Remember the wind load.

 

[rs14smith]

Hmmm, I guess it would help if I showed you my drawing of what I'm trying to do

Here is a short video clip, **broken link removed**, I made of the tracker design I have in mind. It's only a single axis tracker so that's why I only need 1 servo motor, sorry for not stating that.

Anyway, this setup seems fairly simple, again, however, I just have little experience with gears, and picking the right motor for that gear...

The gears in the video are 1.5" in diameter, which may not be exactly what I need, but I'd like the gear to be at least that large.

As far as using servo motors, I'm not 100% sure if they will have enough torque to move the 2.2lb solar tracker left/right? And most solar tracker circuits interface with DC motors or in other words, usually have connections for regular (2 wire..black -/red+) dc motors.

 

[KeepItSimpleStupid]

I used to do A LOT of gear ratios some 30 years ago. Kinda forgot how. You should at least estimate the amount of torque by using a weight and vary the distance to the center line. T = f * d. The 1 lb can of beans can be force.

One of the best places to get stuff like that is: Spur Gears, Helical Gears, Miter Gears, Worm Gears, Worms, Anti-backlash Gears, Anti-backlash Worms and Bevel Gears from SDP/SI

I use them when i can. Another place that's useful is **broken link removed** and for a superstore **broken link removed**

 

[rs14smith]

hmm okay, well the Torque in my case would be:

Find T?
Let F = 2.2lbs = weight of solar panel
Convert to Newtons: 2.2lb x 4.45 = 9.79N
Let D = 4 1/2inches = distance from center point of gear to end of solar panel
Convert to meters: 4.5" x 0.025m = 0.1143m

So,

T = 9.79N x 0.1143m = 1.12 Newton meter = 158.6ounce-inch

I think my math work is correct?

 

[cr0sh]

If the panel is mounted on bearings and well balanced, then you can easily get servo motors with the torque needed (I've seen r/c servos with 200+ oz/in torque - they aren't cheap, though). Since you mention the need to drive the gearmotor directly (ie, from an h-bridge), what you could do is remove the servo's control PCB, and solder wires directly to the motor in the servo (effectively turning it into a gearmotor). Otherwise, you are going to be looking at using a regular DC gearmotor. If this is a one-off project, then I would recommend you go with surplus gearmotors (my experience has been with Pittman gearmotors, which are very well built, have a wide range of torque and RPM outputs, with ball-bearing or oilite bushings on the output shafts - but they aren't anything like cheap brand new - however, surplus they can be found reasonable). Also, is your design fixed, or is it flexible? That is, do you need the motor where you have it (not a bad design insofar as keeping it out of the weather)? If you can change your design, you can open up other possibilities (such as the already mentioned linear actuator). You also haven't said anything about a budget, or if you are looking for new parts, etc; for instance, those Pittman motors I mentioned cost well over $100.00 brand new, but can be found surplus for $20-50.00 depending on the options (higher prices are generally those in really good condition with encoders on the output - which you may or may not need). I can also tell you where you could possibly get new gears or surplus gears - without knowing more about your budget, project flexibility, and whether this is a "science experiment" or something to see actual use 24/7/365 - its more difficult to make recommendations.

 

[rs14smith]

If the panel is mounted on bearings and well balanced, then you can easily get servo motors with the torque needed (I've seen r/c servos with 200+ oz/in torque - they aren't cheap, though). Since you mention the need to drive the gearmotor directly (ie, from an h-bridge), what you could do is remove the servo's control PCB, and solder wires directly to the motor in the servo (effectively turning it into a gearmotor). Otherwise, you are going to be looking at using a regular DC gearmotor. If this is a one-off project, then I would recommend you go with surplus gearmotors (my experience has been with Pittman gearmotors, which are very well built, have a wide range of torque and RPM outputs, with ball-bearing or oilite bushings on the output shafts - but they aren't anything like cheap brand new - however, surplus they can be found reasonable). Also, is your design fixed, or is it flexible? That is, do you need the motor where you have it (not a bad design insofar as keeping it out of the weather)? If you can change your design, you can open up other possibilities (such as the already mentioned linear actuator). You also haven't said anything about a budget, or if you are looking for new parts, etc; for instance, those Pittman motors I mentioned cost well over $100.00 brand new, but can be found surplus for $20-50.00 depending on the options (higher prices are generally those in really good condition with encoders on the output - which you may or may not need). I can also tell you where you could possibly get new gears or surplus gears - without knowing more about your budget, project flexibility, and whether this is a "science experiment" or something to see actual use 24/7/365 - its more difficult to make recommendations.

Well I'm only working with a small 5Watt panel here, so ideally, this is something that would sit inside on a desk in front of a window. So that's why I don't need a expensive linear actuator.
I would hope not to spend no more than $40 or $50 in parts for the motor/gears for this small project.

I was hoping a motor like this would do: **broken link removed**
It has 22 Lb-in of torque, so that is more than enough to handle the weight of this solar panel.

As for the design being fixed or not, it doesn't have to be this way, but I kinda prefer it to be since it's something that I'll keep inside and want the size of it to remain small.

 

[Mr RB]

Try at the car wrecking yard, you can get a windscreen wiper gearmotor (worm type) that has a ton of torque and are good for that application.

Or if you want to pay more for a new gearmotor try the robot stores (or surplus stores) for "12v DC worm-drive gearmotor" or similar.

 

[KeepItSimpleStupid]

The specs say W. Not sure if they mean WHP or Watts. Current is conveniently left out. See: Horsepower - Wikipedia, the free encyclopedia.

I hate electromechanical parts. They get expensive quickly.

You don't have wind loads to deal with. It's just for show. You may be able to get by using Ladder chain and two sprockets and your gear motor. Remember to put limit switches to limit the travel.

What did you use to do the 3D thing?

It's the stupid things that add up. The bearing supports. One or two point. Oilite. Undersized reamers. Pressed into place. Shaft collars. Thrust washers. Precision shafting. Shipping. Getting the holes straight. I used to have full machine shop access and I did a couple of neat motion control gizmos.

 

[rs14smith]

The specs say W. Not sure if they mean WHP or Watts. Current is conveniently left out. See: Horsepower - Wikipedia, the free encyclopedia.

I hate electromechanical parts. They get expensive quickly.

You don't have wind loads to deal with. It's just for show. You may be able to get by using Ladder chain and two sprockets and your gear motor. Remember to put limit switches to limit the travel.

What did you use to do the 3D thing?

Yeah using sprockets was my plan B idea if I couldn't find a simple solution for the current design. A few of my friends know how to design sprockets on AutoCAD so it shouldn't be too difficult I'd think.

The 3D program used is Google SketchUp, which is one of the best Free programs I own to date

 

[ronv]

I have used motors similar to the one you saw on EBay. Worked fine. The nice thing about the 6mm shaft is that you can mount a pot for feedback to the shaft if you need it. Pots available from Mouser. I would buy a real slow one and do away with the additional gears.

 

[cr0sh]

The motor you posted would work, although it would be a bit of overkill. Here's some links you might want to check out for surplus stuff:

All Electronics | Electronic and Electro-Mechanical Parts and Supplies at Discount Prices
Alltronics
**broken link removed**

I've had good experiences with all three of these companies.

If you wanted to go with new components:

AMETEK Technical and Industrial Products
Precision Mechanical Components Timing Belts Pulleys Spur Gears Couplings Bearings Sprockets Retaining Rings Brakes Helical Gears Clutches Universal Joints
Boca Bearing Company :: Ceramic Bearing Specialists
Firgelli Technologies - Micro Linear Actuators
Linear Actuators, Linear Motors, Micro motors, Electric Motors
igus - Plain Bearings, Linear Guides, Cable Carriers, Continuous-Flex Cables

McMaster-Carr

Of these, I've only dealt with boca bearings (needed some bearings for a pittman gear motor - they had them) and ametektip (their customer service is great, but their prices are "precision industrial" level - I wanted a single gear for a pittman motor; they would only sell me a minimum of 50, for $7.00 each - but they were willing to sell to me as an individual through a local rep, so that was something interesting and worthwhile to find out).

Finally - here are some possibilities for your frame, too:

80/20® Inc. - The Industrial Erector Set�
Faztek T-Slotted Aluminum Extrusions / Modular Framing Systems
FRAME-WORLD Structural Aluminum Extrusions
MicroRAX
MakerBeam - SparkFun Electronics
Contraptor
Grid Beam Building System
Grid Beam -- the easy building system everyone can use

I know you already have a design, but going with a t-slot or gridbeam-type solution for the frame may be a better solution for getting up and running in a bolt-together fashion (although it likely won't be cheaper in materials cost). Note that for 80/20 - they have an Amazon store where they sometimes have some good deals; the smallest t-slot they sell via that store (or maybe altogether) is 1-inch standard...