A stepper motor is part of a total mechanism that produces the necessary torque and speed (required load point) to provide motion to a load – to move it, focus it, lift it, inspect it, etc. There are several performance requirements that must be considered when selecting a stepper motor for an application. In general, the chosen motor solution must produce the necessary load torque, speed, and motion profile requirements, fit in the available space (physical envelope), and perform as required with the available voltage.
The fastest and most reliable way to determine these needs is with a motor sizing tool. These tools calculate motor load points and then analyze the load and motion profile to generate a list of possible motor matches from the step motor database. By determining the step motor performance curve, temperature profile (an output of the sizing tool), and motor operating voltage, the best step motor option can be found.
Step motors are available in a variety of technologies that can affect selection decisions. Two prevalent step motor styles are the tin-can and the hybrid configurations. Tin-can step motors are typically a lower cost solution, cover the lower end of the holding torque range, and have step angles ranging from 0.9 to 18 degrees. Hybrid step motor designs cover a wide range of holding torque option, are typically used in higher precision applications, and are available with a range of step angles (with 1.8 degrees the most common). Windings are available in both unipolar and bipolar configurations.
Careful consideration of the motor load and available motor voltage requirements are necessary to select the proper stepper motor solution.