Greetings!!!
Anyone know the correct way to calculate a motor's torque? To lift up 1kg thing by using a stepper motor...

thx..

 

YOu need to know the lever arm's length (or the radius of the wheel). Basically you need to know the distance between where you want the force applied and the center of the output shaft (of the motor or the gearbox, whichever is last stage in the transmission).

THen you just go:

T = F x L

THat is the MINIMUM torque you need to HOLD the load STILL against gravity. If you know the acceleration required then you can do more. (ie. use F=ma, and then use your calculated F in the first equation.)

 

can u introduce me any good website for me? with examples? thx

 

Roman Black did some torque testing on his site below is the link http://www.romanblack.com/stepper.htm

Cheers Bryan

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thx yao... this is a good website!!!

 

At low speeds a stepper motor's torque is approximately equal to its holding torque. It is all downhill from there. As the speed increases the torque decreases until you reach a speed where the motor stops altogether as the step pulses continue with reckless oblivion.

In a DC motor there is a Torque Constant K-sub-T which when multiplied by the current gives the torque. By Newton's second law this is equal to the moment of inertia, I, of the rotor times the angular acceleration in radians/sec/sec. If you know three of the four you can compute the remaining one.

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