I am supprised that no one has posted this before. I thought of it years ago when thinking about motors to use in robots that had a lot of power.
When is the last time you sat in an automobile that had power seats? Did you ever wonder how a little motor could raise or lower the seat even when two people are sitting on the seat. It uses stepper motors with a lot of torque. The same goes for the power windows, ie. small motors with a lot of torque. They are all 12 volt and reversable.
I have tried several times to post pictures of a super powerful arm using motors of this type but for some reason I have not been able to post such a criter.
Oh well, I was able to give you all this infomation which may help some of you who are looking at building larger projects.
Bill
thats neat. Sure would like to see pics.
All of those mechanisms that I have seen use normal DC motors with big gear reductions, rather than steppers. This is not to say that it couldn’t be done with steppers - just that I haven’t seen any such mechanisms using them.
(I should also note that I don’t make a habit of disassembling car seats to examine them, either)
You could be right but I did read that they were stepper motors on another site some time ago. Being as I have not checked them out myself can not swear either.
Bill
The motors used in power seats are large 12V DC motors with massive gear reductions on them. Basically like a windshield wiper motor only geared down even more. the problem with them is that they are so slow. Loads of torque, but very low RPM.
But I’ve never heard of anyone trying to overvolt them to maybe, 16 Volts? Could increase the RPM considerably if they can take it.
But it would decrease the life most certainly.
Why speed them up. Does anyone know how fast they are. Even they only turned 5 rpm, if they were connected to your drive wheels that actually may be to fast for your bot. Instead of a small gear connected to you motor and a larger gear connected to you drive wheel you just might be able to reverse them. After all they have a lot of torque.
I know of a site that sells something like this. I am going to search for it once again and then post the like.
Bill
Once again to those who don’t know I work on developing large robots so the size of the motors is not all that important.
This site sells a couple of windshield wiper moters and they don’t look that big to me. Maybe on a small bot?
sciplus.com/categorySpecial.cfm
Bill
I loved the American Science and Surplus catelogues I got when I was little. But then I was that kind of kid. Nice to know they’re a) still around b) Finally put real pictures of their items on the web page.
Your not thinking of Edmund Scientific are you? It was always very popular with young people and still is.
They are on the web too.
Bill 
No I really mean AS&S. Edmund is far too overpriced mainly since they have approved vendor status so they price to essentially “rip off” schools. I got the catalgoues with the little cartoons of the products (like they still have on the website). I never really ordered much from them despite the hours upon hours of looking because I was never sure what I was actually going to get. I did eventually order a few low cost items and while some turned out really good, others were total duds in person so I moved to other suppliers. Sorry if you work for them or something.
I have found them overly expensive for little things, maybe that’s why I never bought anythig from them.
Just a quick post to say: AS&S is a great resource for the tinker, who is willing to work with sometimes-questionable merchandise, in exchange for great prices. Their catalog is usually a pretty good read for the product descriptions (though they were better back when AS&S was JerryCo, before Jerry died), but yes, it’s a very good thing that they’ve added actual photos to the website, as they’re often critical in determining exactly what you’re going to be getting for the price. They are, first and foremost, an industrial surplus house, so it’s important that you keep in mind that that’s exactly what you’ll be getting - industrial surplus - be it misprints, obsolete tech, or stuff that just didn’t sell, sometimes for a very good reason. They’re a great source for many things, especially if you’re willing to buy something for the parts, and do a little bit of disassembly to get to them.
Also, if you happen to be in the neighborhood, a trip to one of their “bricks and mortar” stores is really something else. Back in school, I took a bunch of people from the drama department (they were doing a play for which they needed a number of body bags - for some strange reason, I was the only one who knew where they could get them) to the original JerryCo location, and the Faculty member in charge of the expedition was the one who didn’t want to leave.
For what it’s worth, I agree entirely with the previous assessment of Edmund Scientific. Interesting stuff, but they’re very, VERY proud of their merchandise, and price it accordingly. I consider them to be a resource of last resort, as you’ll usually end up paying several times a fair price for what you get. If you’re looking for optics, their spin-off, Anchor Optical Surplus, has better prices on experimental-grade lenses and optics, but you still pay a lot for what you get. Their primary advantage over a surplus house is that you get to choose the specifications of the lenses and such, and can come back to order more later, whereas with surplus, you takes what they’ve gots, and when it’s gone, it’s usually gone.