# To find power to be used to rotate a circular disk

1. Jun 10, 2014

### chethankc

A circular disc of 10 feet radius has to carry
load 5 tonnes and it has to rotate very slowly say .. 1 rpm. how much power hp motor should be used? Can Anybody help me with thie..

2. Jun 10, 2014

### Staff: Mentor

Hi chethankc. http://img96.imageshack.us/img96/5725/red5e5etimes5e5e45e5e25.gif [Broken]

What equations do you know that may be applicable here?

EDIT: I assumed you are a student asking about a homework question. But please correct me if I am wrong.

What sort of bearing is this turning on?

Last edited by a moderator: May 6, 2017
3. Jun 10, 2014

### chethankc

Hi, I have found the below equation:

HP = (F *R * N)/5252;

where
HP = Horsepower,
F = Force,
R = Radius = 10 feet,
N = RPM which is 1 rpm...

Kindly let me know if this is correct... How would i calculate force with the above parameters.

Thanks

4. Jun 10, 2014

### Staff: Mentor

That may be a valid equation, but there are other considerations.

Perhaps you should explain your application, as well as the bearing. The HP needed will probably be dictated by the effort needed to get the machinery moving from standstill, rather than what is needed to keep it smoothly turning. Others will have to advise you, I can see this calls for someone with practical experience in motor use.

What electrical power do you have available?