News: Ask Applied

We offer different incremental encoder options for our stepper motors. Encoders are used to provide feedback to the motor drive or controller and improve overall performance of the step motor system. The following provides a summary of those encoder options.

Step motor motion is conceptually simple: Just rotate the stator field and the rotor will follow, so long as you don’t expect it to violate the laws of physics.  An easy but unpleasant way to violate said laws is to ask for more acceleration than the motor can achieve.  So how does one perform step motor trajectory calculations? As we learned in the post Dynamic Torque & Step Motor Sizing, maximum acceleration is determined by torque divided by inertia.

In our post Step Motor Heating we looked at step motor losses over a wide range of speeds and power supply voltages. Now, we deepen our examination. Step motors waste power in two ways: copper losses that result from the electrical resistance of the stator coils and iron losses from magnetic hysteresis and eddy currents. In both cases, this lost power results in the motor heating.

Though it's long been rumored that step motors are driven by tiny hamsters on wheels contained inside, I can assure you that this is not only untrue, but also promulgated by unscrupulous pneumatic actuator salesmen.  So how does a step motor work? In reality, step motors operate by electromagnetism.  Specifically, a permanent magnet rotor such as the one shown below is attracted to electromagnets that reside in the stator.

If you are new to step motors, you may be wondering how to mount one in your application. You’ll need to be concerned with three things: piloting the motor, fastening it to the mounting surface, and coupling the shaft to your load.