A stepper motor has the following properties Holding torque

A stepper motor has the following properties: Holding torque: 50 in. oz Dynamic torque: 30 in. oz Detent torque: 5 in. oz The stepper motor will be used to rotate a 1-in. diameter printer platen. The force required to pull the paper through the printer is estimated to not exceed 40oz. The static weight of the paper on the platen (when the printer is off) is 12oz. Will this stepper motor do the job?

Solution

first we need to calculate the torque required to rotate the platen during printing

so,

torque = force * radius

we have force required to pull the paper is 40 oz and radius = 0.5 in

torque = 40 oz * 0.5 in

torque = 20 in.oz

so we can say that the motor with around 30 in.oz of dynamic torque will be strong enough to pull the paper.

now find the torque of the platen form the weight of the paper

torque = force * radius

torque = 12 oz * 0.5 in.

torque = 6 in.oz

so When the printer is on, the powered holding torque of 50 in.oz is more than enough to support the paper.

but when the printer is off, the weight of the paper exceeds the detent torque of 5 in.oz, and the platen will spin back.

so we can say that mototr can not do the job