Rotational Energy

[HiroJ]

Hi,

This is my first time posting, I hope you can help.

 

Designing a belt system. Two pulleys, two tensioners. 5 m circumference of belt.

Found moment of inertia of pulleys and tensioners

Found moment of inertia of belt

added the two: 0.742750068

 

then used K.E= 1/2 * I * omega^2

to get rotational energy at full speed (1200 rad/s)

K.E = 53478004.91 joules

SEEMS EXCESSIVE!!

want to find motor power required to run this. so i chose an acceptable start up time 60 seconds for the 187 kg belt to reach 30 m/s however this told me

I'd require a 891KW motor

 

Can anyone help me figure out where im going wrong??

 

p.s. mass moment of inertia for belt was calculated as belt total mass at driver radius.

[insane_alien]

1200rad/s seems an excessive rotational velocity are you sure you didn't mean rpm?

[HiroJ]

Oh my god.. thanks for pointing that out! Its actually 200. i didnt notice it was so large because i have my calculations in a very messy excel sheet...thats rad/minute... not an SI unit by any stretch of the imagination. This should change a lot. Thanks!! I'll see what happens and post back here