24V Saturn Conversion

24V Saturn Conversion

When Heath and I were designing a drive system we were looking at a motor that had a lot of torque and was cost efficient. We wanted motors that would be able to haul around a 100lb droid. We chose the Saturn Wiper motor as it has enough torque, is inexpensive and easy to find.

After attempts at a reverse gear and such a fellow builder (Craig) informed me that a local robot group was converting the motors to 24V for their robots. As I understood it the 12V motor uses only half of the windings. This conversion uses all the windings at 24V. This reduces the RPM but increases the available torque.

So with the same sprockets in theory the speed would be the same as before. With more torque and the theoretical same speed forward and reverse I can increase the main drive sprocket size and get a faster droid.

01tso.jpg
01tso.jpg

This spring and brush is not needed and has to be taken out. Actually go to step 10 and remove the entire assembly and return here

02sto.jpg
02sto.jpg

Here is the spring taken out. Later on I realized that I can take out the entire assembly (Step 10)

03cic.jpg
03cic.jpg

We need to then cut the coil at this location

04ccb.jpg
04ccb.jpg

You have to cut as close to the base as possible which will allow some flexibility for soldering later on

05co.jpg
05co.jpg

Here is what it looks like cut

06cooc.jpg
06cooc.jpg

This coil is not needed so it can be cut off completely

07ctbr.jpg
07ctbr.jpg

Coil to be removed

08cg.jpg
08cg.jpg

Coil gone

09csas.jpg
09csas.jpg

Return to the first coil that had one end cut off. Swing the coil around so the cut end lines up with the wire from the coil you just removed. Be gentle as too much bending back and forth could break off the coil

10tnn.jpg
10tnn.jpg

When I got to this point I realized that this entire assembly can be removed and not affect the motor at all

11gone.jpg
11gone.jpg

Gone - quickly ripped out with a pair of plyers

12swcw.jpg
12swcw.jpg

Solder where coil was - Now we solder together the final connection

Conclusion
I have run this setup at a 3 day hobby show with no problems. I am happy with the added speed. It s a quick walk which is great. I was worried about the controllability at slow speeds but it was fine. I did not notice overheating or any electrical problems. It will not win any speed contests but I don't mind.

The hobby show had a carpeted walkway which was no problem. I am not sure about plush stuff.

If you want to build your own R2 go here --http://groups.yahoo.com/group/r2builders

or here --http://movies.groups.yahoo.com/group/astromechs

for an R7 go here --http://movies.groups.yahoo.com/group/r7droidbuilders

Email me ask@interlog.com