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Electronics => Electronics => Topic started by: magnetman12003 on January 04, 2010, 12:33:03 PM

Title: Small motor search- Need help
Post by: magnetman12003 on January 04, 2010, 12:33:03 PM
Hi All,

I am new to this forum and dont know much about small DC motors. I see many availabe however on the internet at low cost.

What I need as a small dc motor with hi torque and low current draw as my prime targets. The motor will be operated from 3 to 14 volts  delivered by my variable DC  model train transformer power supply.  The speed should be higher than 1,500 rpm.

Hi Torque is my prime target and I dont want to aquire that through a gearbox

Which particular motor might you recommend and where can I buy it. All suggestions welcomed.

Thanks, Tom

Title: Re: Small motor search- Need help
Post by: little-c on January 04, 2010, 03:31:15 PM
just out of curiosity, any size, wieght or cost restrictions?

is that 3 to 14 volt dc, used to control speed of motor?

it might be useful to use a PWM instead of changing the voltage. (tutorials on it somewhere, read through the dc motor tutorial, its linked in there I think) though that requires some extra work. and I don't know if it would work on a train track...
theoreticaly its just a giant wire. with assciated effects of amplifing annoying quantum physics stuff and other stuff we like to ignore...
(I may have gone off on a random tangent, which is normal, don't worry!)

most stuff I have found in a quick google search is high torque or high speed, but not both.

do you have figures for torque and current draw?

high torque low current are not things I tend to look at. my style tends to be more attaching it to a giant Pb battery, and having another power supply for the controler.

any reason for not wanting a gearbox?



another option is ringing up one of the suppliers like active robots and asking them if they could advise you on a suitable motor for your requirements?
Title: Re: Small motor search- Need help
Post by: madsci1016 on January 04, 2010, 04:45:45 PM
FYI,

torque = current. They are proportional.

To ask for a "low current, high torque" is like asking for a 50mpg engine with 750 horse-power;  it doesn't exist.

As for recommendations, I have no favorite companies. I just use google till i find one with specs i am looking for.
Title: Re: Small motor search- Need help
Post by: waltr on January 04, 2010, 09:12:21 PM
Every one's info above is correct.
However, don't over look a gear box to gain some torque. There are many highly efficient motors that run at over 20000 rpm so you will need a gear reduction to get the 1500 rpm you need. This also increases the torque.

Just some links:

Motors and gear boxes for model trains.
http://www.nwsl.com/motors-power-drives/pittman-12-volt-dc-permag-can-motors (http://www.nwsl.com/motors-power-drives/pittman-12-volt-dc-permag-can-motors)
http://www.micro-loco-motion.com/ (http://www.micro-loco-motion.com/)

High quality motors and gear boxes:
http://www.micromo.com/ (http://www.micromo.com/)

Good price for the quality:
http://www.pololu.com/catalog/product/1099 (http://www.pololu.com/catalog/product/1099)
or
http://www.pololu.com/catalog/product/1100 (http://www.pololu.com/catalog/product/1100)


Now you need to define the torque you require and decide on how much you are willing to pay.