Torque

[cboughton]

I am trying to calculate the torque required to rotate a mass around a shaft. See attached.

20140519094434670.pdf

m = 315 lbs.
w = 10"
h = 16"
d = 9"
r = .75"

T = Iar (a is angular accel.) (r is

I = I₁+md²
I = 1/12 mw²+ 1/3 mh² + md²
I = 2625 + 26880 + 25515 = 55020 lb-in²

Mass rotates 90 deg in 3 sec.
average speed = pi/2 * 1/3 = pi/6
pi/6 = at
a = pi/18 rad/s²

T = 55020 * pi/18*.75

T = 7202 in-lbs

My biggest problem is calculating the angular acceleration (a). I know i did not do it correctly. THe mass rotates from rest (0 degrees) to 90 degrees in 3 seconds.

[cboughton]

PS.. I am trying to size a quarter turn actuator which is why i need the torque. I am trying determine if i can drive 3 of these sections off of (1) actuator.

The mass is a load on a platform and the shaft will be rotating to dump the platform. I have multiple platforms in series. Therefore, my max torque will be the initial torque, since once it starts rotating the mass will continually drop. Once i have passed 45 deg gravity should assist.

[Kelly_Bramble]

Check the following webpage and Calculator -->

Mass Moment of Inertia Equations

Mass Moment of Inertia Rectangular Block

[jackieann000]

The above ideas are very clear and fine regarding the torque. Thios is also beneficial in case off engeneering purposes.