Motor advice: what to get?

My team and I are building a 15 lb robot for a battlebots competition but need help finding some good motors. The ideal motors would b 12v, at the most 1.5 lbs, run between 500 and 800 rpm’s, are at most 3.5 inches wide and at most 5 inches deep. These will be carrying around the entire robot so the need to be good. If anyone has any info. on some motors like this or very close to it, or knows of a place where I might get some, please post.

P.S. I’ve tried robot market place.

I suspect that you are not familiar with the FIRST competiton.

We use (and are limited to) the motors provided in our basic kit of parts. Because FIRST is an organized competition, we build along certain guidelines. These being our dimensional limits and our weight limit. If you are building for FIRST, you know what you can and can not use, and how much weight you have to work with, if you are not building for a FIRST competition, we need more specifics. Plenty of people on these boards know a thing or two about motors, but we need to know how much weight you really have to work with. There are all numbers of different motors that weigh less than 1.5 lbs. We also need to know how big you plan to make your robot, as well as the desireable speeds you are seeking.

Hope we can help you.

Check and and search eBay separately for “battlebot” “battlebots” “battle bot” and “battle bots”

try to find CIM motors…They rock…

what compettition would this be for?

Couple links that are relevant to this topic

I would think about hacking a 12V cordless drill motor and gearbox from a Harbor Freight or Homier 12V cordless drill. You can get the whole drill from either place for $10 and it is pretty much ready to use and you have a battery pack as well. Take a look at the second link in sanddrag’s post.

If you have the $ and want to just buy a mount instead of making one:

You could always just cut up the drill case and use it as a mount as well.

Search on Google and you will turn up a ton of links to Battlebot robots that use cheap drill motors and gearboxes.

I’ll echo the comments already made.

For your application, you want a motor that is powerful, rugged, light and inexpensive. For those traits, you can’t do much better then a cordless drill. A drill motor has to be strong enough to drill through metals, rugged enough to survive drops, light enough to be used by a normal human all day and cheap enough for a normal human to afford. It’s a pretty good match for robots in harsh places.

Not only will the motors be powerful for the size, they come with a bullet proof gearbox attached that should put speed and torque right around where you want it. One more reduction after the gearbox should be all you need. I can’t stress the importance of having a built in reduction- no motor this size is going to have a free speed under 10000 rpm, so they’ll be pretty useless with out some serious reduction. Trying to build your own gearbox may be more then you want to attempt, it will certainly weigh quite a bit.

Also, consider keeping the drill casing intact and using it as a motor mount. It’s been designed to perfectly hold and protect the motor and gearbox, you’re unlikely to find something better.

If you think a drill motor might be to much, or otherwise no good, perhaps you could use what we in FIRST refer to as a FP motor. The Fisher Price motor is used in the little electric buggys kids can ride around in. They are actually made by a few different companies and can have slightly different specs. Most however are 12 volt motors that produce a peak of around 100 watts. Most also mate to plastic gearboxes, which provide a easy, if not terribly reliable reduction.

Any of this helping?

-Andy A.

Unless it happens to be made by Bosch :stuck_out_tongue:

Bad Cory!

You know we never say the ‘B’ word anymore.

-Andy A.