# Torque requirement calculation

• 02-19-2019, 04:23 PM
switzerf
Torque requirement calculation
I want to have a linear type actuator reciprocate a table back and forth on 15 inches travel each way. The required force would be equivalent to a straight gravitational lift of 300 lbs. The table is to reciprocate at a speed of 1 to 2 rotations a minute. How do I calculate the torque requirement of an electric motor to drive this. What type and size of motor would work best? :banghead:
• 02-20-2019, 12:45 AM
Hudson
Most mechanism to accomplish this motion will require a gear reduction. Since we don't know the motor speed, friction etc. it is not possible to give you a direct answer.

You want to move 300 lbs, 5 feet in one minute (four complete cycles) so the actual calculated power is 1500 lb-ft/minute or roughly .05 hp. The friction in your drive mechanism might be nearly as much. How dirty is the work environment? Does it work continuously? How much room do you have?

Have you looked at a linear stepper motor arrangement?
• 02-20-2019, 11:28 AM
switzerf
Clean room temperature environment. Operate in continuous 230 minute cycles.
3' wide X 1' high X 3' linear. What would the stepper component configuration be?
• 02-20-2019, 05:34 PM
Hudson
You might look at a stepper motor and ball screw configuration that would be positioned under the table to provide linear force.

Look for a 400 mm travel length linear stepper motor on Amazon. Now you are going to need a controller or driver and computer to send pulses to the motor to advance the table at the correct speed and distance. Some understanding of the motor/controller function will be required to hook things up. There is info on line of course.

Some stepper motor configurations increase in length as more power output is generated. If your motor gets too hot, you can get a longer, more powerful unit, if it fits.