Calculating Torque to Accelerate

In summary, a person is seeking help to calculate the horsepower needed to accelerate a pipe assembly that is supported by a bearing and shaft and has a total weight of 8500lb. They have calculated the moment of inertia and angular velocity, but are unsure if their calculations are correct. They also mention using a hydraulic motor to rotate the system.
  • #1
ram18
15
0
Hi,
I need to find out horsepower to accelerate pipe (40ft long) which is fixed with the plate (10ft x10Ft x 1inch) and whole assembly supported with bearing and shaft. I need to accelerate and decelerate this assembly 180 degree in 10 second ?

Plate weight = 4000 lb
pipe weight = 4500 lb
total weight = 8500lb.

bearing and shaft is perpendicular with respect to plate and pipe in the center

I done this calculation but its seems wrong can anybody tell me what i have to do for right solution . where i am wrong ?


Torque = moment of inertia x Angular acee

Power = Torque X angular velocity.

so i find out moment of inertia for plate and pipe .
Plate
Moment of inertia = mass X a X a / 6 = 4080 X 10x10 / 6 = 68000 lb-ft2.

Pipe ,

Moment of inertia = 647441.66 lb - ft2

Total M.O.I = 715441.66 lb - ft2.

i want to rotate this thing 180 degree in 10 second. so i consider 3 rpm .

angular velocity = 2pixn / 60 = 2x3.14 x3 / 60 = 0.314 rad/sec

angular aceen = change in velocity / time interval = 0.314 / 10 = 0.0314 rad / sec2.

avg angular velocity = 0.314 / 2 = 0.157 rad / sec

torque = total m.o.i x angular acee = 715441.66 x 0.0314 = 22464.86 lb-ft2 / sec2

power = torque x avg angular velocity = 22464.86 x avg angular velocity = 22464.86 x 0.157 = 3526.848 lb-ft2 / sec 3.

1 hp = 17696 lb- ft2 / sec3

so 0.30 hp required to rotate whole system in 10 second. it seems wrong. Can you guys give me some direction on that.

Thanks.
 
Engineering news on Phys.org
  • #2
hi ram18! :smile:
ram18 said:
I need to accelerate and decelerate this assembly 180 degree in 10 second
…
angular aceen = change in velocity / time interval = 0.314 / 10 = 0.0314 rad / sec2.

doesn't it mean that the angular speed will be zero every 10 seconds, with a constant acceleration for 5 seconds, and then a different constant acceleration for the next 5 seconds?
 
  • #3
Actually i want to accelerate that assembly 180 degree in 10 second. I think all load is carrying by bearing so how can i calculate how much torque required to rotate this whole assembly. i m so confused now please give me some right direction.
 
  • #4
ram18 said:
Actually i want to accelerate that assembly 180 degree in 10 second.

do you mean from 0° to 180° in 10 s, then from 180° back to 0° in the next 10 s, and so on? :confused:
 
  • #5
Yes tiny tim can u help me on that .
 
  • #6
ok, then that means that you need constant acceleration from 0° to 90° in 5 seconds, then an equal constant deceleration from 90° to 180° and back to 90° in 10 seconds, and so on …

how much is that acceleration? :smile:​
 
  • #7
Actually i want to rotate that system 180 degree in 10 second . can u tell me my above calculation is right or wrong for that please.

Thanks,
 
  • #8
ram18 said:
Actually i want to rotate that system 180 degree in 10 second . can u tell me my above calculation is right or wrong for that please.

Thanks,

I don't understand …

what angular speeds do you want it to have at the angular displacements of 0° and 180° ? :confused:
 
  • #9
i am going to use hydraulics motor to rotate that system 0 to 180 degree . And i want to know how much torque required to do that?
 

What is torque and how does it relate to acceleration?

Torque is the measure of a force applied to an object to cause rotation. It is calculated by multiplying the force applied by the distance from the axis of rotation. The greater the torque applied, the greater the acceleration of the object.

How do you calculate torque to accelerate an object?

To calculate torque to accelerate an object, you need to know the force applied to the object and the distance from the axis of rotation. The formula for torque is torque = force x distance. The resulting torque can then be used to determine the acceleration of the object.

What units are used to measure torque and acceleration?

Torque is typically measured in units of Newton-meters (N*m), while acceleration is measured in units of meters per second squared (m/s^2). These units can also be converted to other units such as foot-pounds and feet per second squared.

What factors affect the torque required to accelerate an object?

The torque required to accelerate an object depends on several factors such as the mass of the object, the force applied, and the distance from the axis of rotation. Additionally, the shape and distribution of the object's mass can also affect the torque required.

Can torque be negative in the context of calculating acceleration?

Yes, torque can be negative if the force applied is in the opposite direction of the desired rotation. This can result in a negative acceleration, meaning the object will decelerate or rotate in the opposite direction.

Similar threads

How do I calculate wheel radius using below data?
    • Mechanical Engineering
Replies
1
Views
580
Torque calculations: Rotating vertical shaft
    • Mechanical Engineering
Replies
5
Views
3K
Agitator Torque Calculation
    • Mechanical Engineering
Replies
2
Views
1K
Automotive Need help calculating load torque and acceleration torque of a vehicle
    • Mechanical Engineering
Replies
8
Views
4K
How Do You Calculate Torque for a Pusher Arm with a Dead Plate Friction?
    • Mechanical Engineering
Replies
1
Views
1K
Can you help me calculate the required torque and power of this motor?
    • Mechanical Engineering
Replies
8
Views
1K
Torque required to spin a hollow cylinder
    • Mechanical Engineering
Replies
2
Views
2K
Torque calculation for a new loading mechanism
    • Mechanical Engineering
Replies
8
Views
1K
How is moment of inertia calculated and translated between units?
    • Mechanical Engineering
Replies
9
Views
5K
Automotive Calculating the angular acceleration of a swivel seat
    • Mechanical Engineering
Replies
3
Views
1K

Hot Threads

Recent Insights

Back
Top