Making a Home Made Solar Tracker

Depends how much wind loading, but I'd think something nice and low geared like an electric window mechanism from a car would be a good starting point.
Speed isn't an issue so you can change the leverage to slow it further/effectively gear it down.
It may not be rubust enough long term, but would be a good start point.
I used a big version of the same type of gearbox (worm & wheel) on my golf trolley.
Del

thanks very much, what type of motor and gear box have you got to drive the Golf buggy, I have 14, 300 watt panels on the roof but fixed panels, I am not happy I am getting the most out of them.

Since there would be quite high wind loading the motor must be able to hold position.

I have read a stepper motor may do that.

what type of motor and gear box have you got to drive the Golf buggy.
Click on the link in my post, all the info is in there, including a link to the motor gearbox supplier 3rd line down in the text.
Here is the link again just click on the underlined blue text.
Del

Review the last few pages of this document for drive train ideas:

http://www.solare-bruecke.org/Bauanleitungen/Manual_ind_07.pdf

This is a simple counterweight/clockwork tracker design, but it may contain some useful ideas for an electric motor drive. Many small gear reduction DC motors should be able to drive fairly large tracking dishes.

Some small examples here:

http://www.sciplus.com/category.cfm/subsection/18

I suggest searching for similar surplus gear reduction motors in your region.

I think you missed the part where you search cr4 before posting a question. This has been discussed a few times before.

Chris -- Following your link to all those previous posts I can see that this has been much discussed. Without studying all that I may be wasting time with one additional contribution to the issue. But it's easier to offer my comment then reread all the previous comments.

Sometime back I got hold of 4 gear motors of a Hospital type bed. They are interesting.

Capacitor type motor (I can't tell if it's capacitor start or capacitor run) 115 volt 1.8 amp rating (=207 watts input) Sounds like maybe a 1/6 hp output. Motor speed is 1750 rpm and the gearhead is 22:1 at a right angle. This drives an 8 TPI 5/8 dia steel acme thread and a large injection molded acme nut guided by a steel cylinder structure about 1-1/2" dia. and some 10 inches long. And it is reversible for the bed application.

I imagine most hospital beds utilize similar size and speed motors. The solar equipment builder would have to fabricate the additional mechanism linkage to change the roughly 3 inches of linear movement in the driven nut of the bed motor to rotation of the solar array frame.

This seems to me just about right for a DIY size solar tracking application and hospital beds are pretty common hardware. I suspect these beds show up pretty frequently on Craig's list. Or one could make contact with a business that sells them that could lead to where old equipment of that type is disposed of and very possibly a free source.

Ed Weldon

I HAVE BEEN IN THE SATELLITE INSTALLATION BUSINESS SINCE 1984. WE STARTED OUT WITH THE 12' C-BAND PARACLIPSE DISHES WITH THE LINIAR ACTUATOR. I HAD TO LOCATE/TRACK FROM 16 TO 32 SATELLITES IN A GEOSTATIONARY ORBIT. THERE ARE SATELLITE TV RECEIVER / ACTUATOR CONTROL THAT COULD BE SET UP FOR PRE PROGRAMMED TIMES TO CHANGE FROM 24 TO AS MANY AS 100 DIFFERENT SETTINGS SATELLITE LOCATIONS AND TRANSPONDERS. I HAVE THOUGHT OF SETTING UP A SOLAR FURNACE AND TRACK THE SUN ACROSS THE SKY. YOU WOULD NEED ONE THAT NOT ONLY TRACKS ACROSS BUT UP AND DOWN. AZMUTH AND ELEVATION. THEY GENERALLY USE 36 VOLTS DC FOR THE ACTUATOR JACK. I HAVE SEEN THEM WORK WITH AS LOW AS 12 ON PURPOSE AND 5 BY ACCIDENT. YOU MAY RESEARCH HORIZON TO HORIZON. 27409

Firstly, 100% accuracy is not needed in tracking the Sun, if you are a degree or two off, that is not a problem.

Secondly, no matter where you are on the world, the sun appears to follow the same path (ignoring summer and winter for the moment) each and every day. You could set your clock by it, many do and did!

The height above the horizon varies very slowly over the year, and could actually be handled by once a month, giving it a small adjustment, high accuracy is not needed. Just tilt the whole mechanism a bit.

So basically you need a simple mechanism that points to the east before sunrise and picks the sun up as it becomes visible and tracks it till it sinks below the horizon.

If you look at a conventional 24 hour clock, the hour hand follows the sun (at least in the northern hemisphere)....

So you basically could use a PIC to drive a stepper motor via suitable gearing to follow the sun "blindly" on its course each day.

The PIC could even be programmed to adjust the angle of the bearing to the ground to follow the arc of the sun through summer and winter....

Note.

A PIC is a computer chip with basically an almost complete computer built in.

Some like the PICAXE have also a Basic Interpreter, that would be much faster than you actually need, already in the, and far easier to program for anyone learning.

All the software you need you can download for free and you can connect a PCs RS232 or USB port to the chip to download your program into it....

The program can also be "tested" using the free software even before you buy anything.....

There are applications already written for driving stepper motors....

Go here to find out more. There are suppliers all over the world, even in Aussie!

If you need anymore info simply ask here.....

So I went into the fish & chip shop and said Fish and chips twice.
The bloke said "I heard you the first time"
Del.... You have a strange concept of 'cheap'

Why post the same ad twice????

Greetings Solar Aussie,

Are you sure you want to use electric trackers?

I'm in the fixed solar biz, but I have heard of a trackers that use hydraulic or air cylinders that work on differential presure from the sun's heat, nonelectric, simple and cheap, and reliable. They were on the web, dont have the link, sorry.

Spacecannon

This thread had the most content

http://cr4.globalspec.com/thread/56459#newcomments

that applies

Del's suggestion of an electric window motor from a car, is good

you already have some dc to run it on