How does torque change as the motor shaft rotates on a DC Motor?

Question

I need to know how torque changes throughout one full 360 degree rotation of the armature/shaft of a DC motor. (Torque vs. Angle Position)

Answer 1

To answer this you have to specify how many poles there are on the motor. The result on a 2 pole motor is much different from a 12 pole.

Answer 2

A servo motor has a pot or encoder to monitor the shaft's rotational position. Often it is used to hold the shaft in place at a specific angle of rotation. The motor torque required depends on the load. Other uses are for precise location as in CNC machines where a feedback loop keeps track of how far the cutting head has traveled. To convert a simple dc motor to a servo motor would require a means of attaching the pot or encoder to the shaft. Then reading the output and using the information to determine the shaft position and/or number of rotations.