# Required Torque on Motor

1. Apr 22, 2014

### PC22

Hi I am trying to work out the torque required to rotate an object from 0 to 1RPM in 1 second (1 second accelerate to 1RMP) , its working in time laps so very small movement is required.

The diameter of the gear is 30mm and the diameter of the shaft is 10mm, the object on top weights 20kg it's sitting on a low friction bearing.

So far I have

Torque = F x r

r = radius of the cylinder = 0.005

Force = mass x acceleration
where mass = 20kg

accel = velocity/time

velocity = r x ω (rotational speed)

where ω at 1RPM = 6.28 rad/sec

So v = 0.005 x 6.28 = 0.0314 m/s

Therefore accel = 0.0314/t

Therefore T = 12 x 0.031/t x 0.005
= 0.186/t Nm

I know there is alot more to this but I am very new to this and out of my comfort zone in terms of engineering knowledge (I'm a product designer) , I've mainly been following pre worked examples I've found online. Would really appreciate some help and guidance.

2. Apr 23, 2014

### Seth.T

Seems like you got the correct answer, So whats the problem?