# Looking for low RPM high torque motors

Hi,

I'm looking for 2 12 Volt DC electric motors for use in a university design project. The motors will drive a device of 20 kg up a 20 degree incline on grass with 2WD. The motors will be connected directly to the two front wheels (200mm diameter) and based on my calculations need to have a torque of 4.5 Nm and a RPM of 90 ish in order to travel at 1 m/s. I have looked around for a long time but i cant find anything like this anywhere.

Thanks,

Tom

Are you in the US? Check out some of these
http://www.mpja.com/DC-Motors/products/100/

Im not im in the UK

I would look at Mabuchi Motor: http://www.mabuchi-motor.co.jp/en_US/product/p_0303.html

They have a wonderful catalog that is easy to navigate and a wide stock of motors. Find them here and you'll know what to buy elsewhere. I've purchased mine from a shop called Parts Express.

Windshield wiper motor? - Scotty

tomorourke94:
Hi,

I'm looking for 2 12 Volt DC electric motors for use in a university design project. The motors will drive a device of 20 kg up a 20 degree incline on grass with 2WD. The motors will be connected directly to the two front wheels (200mm diameter) and based on my calculations need to have a torque of 4.5 Nm and a RPM of 90 ish in order to travel at 1 m/s. I have looked around for a long time but i cant find anything like this anywhere.

Thanks,

Tom

Well no, not without reduction gearing you won't....

I make that about right for torque, you want 10 rad/s for 1m/s with 0.1m radius wheels
so the power per motor is 10 * 4.5 = 45W mechanical, so something like 70W electrical
if brushed motors with low friction gears, 100W+ if realistic geartrain, so expect upto
10A per motor under full load. Motors that size tend to be 3000 or 4000rpm, so a gear-down
of 30 or 40 to 1 seems about right, so about 0.25Nm motor at 3600rpm into a 35:1 gear
train seems to me to be the kind of thing.

[ If you're not climbing continuously you can derate the motor a fair bit I think ]