View Full Version : small dc motors

01-20-2012, 07:53 PM
I am getting ready to start on my pantograph and remember someone had mentioned a company that had small dc motors but I can't find the post. I had thought of using a sewing machine motor with foot pedal but not sure if there is enough hp to do it.
Any help would be apprecated

01-20-2012, 08:44 PM
Surplus Center

01-20-2012, 09:10 PM
Maybe you have a surplus place where you live that might have some window crank motors, rear window wiper motors, or similar. A local store here, Princess Auto, has some that have the worm wheel built-in and will do continuous rotation- you have access to both sides of the gear from outside the gearbox, so they are easy to use.

I think the power level is about right to drive a leadscrew that would be pushing or pulling up to about 20 lbs or so- some guesswork here. I've never had a problem running this type of motor in either direction, though the direction it normally runs is smoother. This is basically a function of how the brushes have seated in, and if you run it in reverse for awhile they will seat in ok for that direction of rotation. If anything, you might find that it doesn't spin as quickly in one direction as the other. This isn't something worth worrying about for the most part. I assume the motors you use will be controlled with electronics, so it boils down to the controller being able to handle the current draw.

If you're looking for higher voltage motors with suitable power, those drink mixer wands (hand blenders) usually have a 120 volt dc motor that could be used. These are direct drive, so there's no worm gears or spur gears to take advantage of. But a simple line voltage circuit would give you the power source to run them. Most of these motors are made by Johnson- look up Johnson dc motors and you will find a selection.

Another 'device' that has a usable motor in it is a basic hand mixer. Most of the cheap ones have something like 3 or 5 speeds, electronically controlled, a permanent magnet dc motor, and two worm gears. I've found them to be easy to re-use. You might check around at some big box stores to find out if there's any returned appliances like these- for the most part the motors don't die, there's usually something else wrong with them. The mixer motors have enough power to run a leadscrew for something small- not enough for a mill table though. The hand blenders have a larger motor.

When I worked in the scratch and dent store, we went through several tens if not hundreds of hand blenders, and some of those had seized motors, but all of the hand mixer motors were good.

Another place to find dc motors is hobby shops. There is a wide range of rc car motors available, and most are fairly powerful for the size- I'd say about equivalent to the hand mixer motor. They usually are wound to run on a fairly low voltage, as low as 7volts in some cases, so maybe that makes them unsuitable. Some of those are fairly inexpensive, as most people in that hobby want the latest and greatest for that extra edge in performance, and won't want to buy the basic motor. There should be lots of them sitting around that a shop would like to get rid of- maybe around $20 or so per. No gearbox again though- and a hobby shop is one of the most expensive places to buy things generally.

I will come full circle and say that the windshield wiper motor/gearbox is where you should start looking, if you can handle the fact that you'll need a power supply for the running voltage, and controllers that will work at the voltage and current.

01-20-2012, 10:22 PM
I just pulled apart a old recliner chair with the massage stuff in it three nice small 24 volt motors and the power supply, there seem to be a lot of them around.

01-20-2012, 10:56 PM
My pantograph uses an off-brand Dremel motor.