# Thread: Need alittle help with motor rating

1. ## Need alittle help with motor rating

hi all,
I have a bunch of these motors http://www.nisca.co.jp/motor_eng/dc_nc5475.html
and would like to know what the oz/in rating is but i'm not sure how to convert the listed rating to oz/in. I am planning on using these on a smaller table, probably around 24x48 and want to make sure they will be strong enough. I do have several so could I use more than one motor on each axis and connect them with a timing belt drive? Not sure how i would mount the encoder then tho as it would only be on one motor. I'm new to servos and am looking at rutex for the controler.

CNC Darren

2. Originally Posted by CNC Darren
hi all,
I have a bunch of these motors http://www.nisca.co.jp/motor_eng/dc_nc5475.html
and would like to know what the oz/in rating is but i'm not sure how to convert the listed rating to oz/in. I am planning on using these on a smaller table, probably around 24x48 and want to make sure they will be strong enough. I do have several so could I use more than one motor on each axis and connect them with a timing belt drive? Not sure how i would mount the encoder then tho as it would only be on one motor. I'm new to servos and am looking at rutex for the controler.

CNC Darren
1 oz = 0.0283 kg

F = m*a
g = 9.81 m/s2

1 oz ~ 9.81*0.283 = 0.278 N

1 in = 0.0254 m

1 oz*in = 0.278 * 0.0254 = 0.00681 N*m

cheers

Why can´t Americans learn to use SI units like the rest of the world? http://www.cnczone.com/forums/newrep...reply&p=59604#
Roll Eyes (Sarcastic)

Smilie

3. Sorry, but my ironic but well intended smileys did not come out the way I thought they would... :-(

4. One mNewton = .001 Newtons. To convert Newton-metres to ounce-inches multiply x 141.612.
So if motor is 147mN/m .147x141.612 = 20.8 oz-inch.
Does that look right?
Also you would be better off looking for the right size single motor rather than trying to parallel servo motors.
Al

5. I think i attached a image. This motor says trq (stall) at 6Nm. Thats really not much if i figured right.53.1045 in/lbs. 850 oz/in i think. For such a big motor it sure don't push much. Do servos do more with less than steppers? My steppers on my router are 2600+ oz/in and the motors are allot smaller than these 3 phase servos.

Donny

www.whiterivermfg.com

6. Servos keep their rated torque up to nominal speed, while steppers drop off in torque with increased speed.

Arvid

N*M to Oz/In no probs!

8. Oz/In, 147mN/m

Torque is force times distance, not force per distance.

Think about opening a door: if you pushed directly on the hinges instead of the handles, and if torque were force per distance, the resulting torque would be infinite (distance = 0) and the door would smash open in an infinitely short amount of time - not exactly the way you would expect a door to behave when you touch its hinges.

Arvid

9. That's why I let my computer do that kind of stuff!