1. ## Torque

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

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.

2. 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.

3. Check the following webpage and Calculator -->

Mass Moment of Inertia Equations

Mass Moment of Inertia Rectangular Block

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

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