Motor with RPM of 1-3

[lottesfog]

HI,

Can anyone recommend a way to make a motor with a low ROM - preferably 1-3? (I am building a lego linear accelerator, and they just don't spin as wheels).

Cheers,

Lotte

[bonox]

The quickest is probably an already low geared motor (a PF XL or a 9V mini-motor (http://www.bricklink.com/catalogItem.asp?P=71427c01)) and put it through a worm gear on a 40tooth gear.

You can then use a train speed controller to run it at it's slowest speed.

If you don't want to speed control the motor, you are left with consecutive reductions like a pair of 8:24, 8:36 etc. Multiply the factors out and you'll get the total speed reduction. (a 12th in this case).

oh, for calculations, a worm is a single tooth, so a worm on a 24 tooth gear would be a speed change of 1/24. You can find motor speeds (at full speed) here:

http://www.philohome.com/motors/motorcomp.htm

[zux]

None of LEGO motors have RMP in your range so you'll have to use gears. Check Sariel's page for better gear+motor combination