To find power to be used to rotate a circular disk

[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..

Man thanks in advance...

 

[NascentOxygen]

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

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?

 

[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

 

[NascentOxygen]

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?

 

[alphy]

To calculate the power needed to rotate the circular disk, we can use the formula P = (T x ω)/5252, where P is power in horsepower, T is torque in foot-pounds, and ω is angular velocity in radians per minute. In this case, we know that the radius of the disk is 10 feet and the load is 5 tonnes (or 11,000 pounds). To convert this load into torque, we can multiply it by the radius, giving us 110,000 foot-pounds. To find the angular velocity, we can convert 1 rpm to radians per minute by multiplying by 2π, giving us 6.28 radians per minute. Plugging these values into the formula, we get P = (110,000 x 6.28)/5252 = 131.8 horsepower. This means that a motor with a power output of approximately 132 horsepower would be needed to rotate the circular disk at a slow speed of 1 rpm with a load of 5 tonnes. It is important to note that this calculation assumes ideal conditions and does not account for any friction or other external factors that may affect the power needed. Therefore, it is always best to consult a professional engineer for a more accurate and precise calculation for your specific situation.