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I'm having trouble with an application involving rotating a 10.8lb device through 60 degrees of rotation using a stepper motor (Hurst 4006-004: step angle .1 degrees, Output speed 3.33 rpm, rated torque at 175 pulses/sec of 162 oz-in). It appears that the motor is underpowered and I may need to increase it however when I try applying some basic physics, I don't see where the motor can possibly be underpowered. Maybe someone can help me. Here's what I have:

Moment of Inertia about the rotating axis: 90.8 lb*in^2

Angular velocity .348 rad/sec

Time to reach full velocity, .25 seconds

I of course am neglecting friction in this simplified analysis (mainly because I don't know how to apply it here. It's a aluminum to aluminum sliding contact joint)

Any insight here on how to properly size a situation like this would be very helpful.

Warmest Regards,

David warren

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# Motor Sizing Help (Basic Rotational Inertia Problem)

**Physics Forums | Science Articles, Homework Help, Discussion**