Stepper motors are constant power devices capable of dividing complete motor shaft rotations into a sizeable number of discrete steps. There are four main types of stepper motor designs:
- Permanent magnet
- Hybrid synchronous
- Variable reluctanc
- Lavet type
In machine builder world, there are endless possibilities into which these devices can be integrated. However, for stepper motors to function properly, they must be sized properly, according to the application.
SEE ALSO: Stepper Motor 101
Here at ControlDesign.com, our editors have spoken with many machine builder professionals who have integrated stepper motors into their applications successfully, and this month I want to point out some of these conversations.
Let's start with our article "Stepping Down and Out." Contributing editor Hank Hogan reported that in the future stepper motors will improve because these devices will be better integrated via networking technology. Hogan interviewed Todd Walker, national marketing manager at Oriental Motor USA, and Walker told him the emphasis will fall more on torque in the same motor size and wider range of steps per revolution.
Hogan used security cameras as an example. He said that using smaller steps cuts down vibration and noise. He also related cost benefits to using stepper versus servos.
Executive Editor Jim Montague agreed with Hogan's findings on the cost benefits of stepper motors. In his article "Invasion of the Stepper Motors," Montague reported that stepper motors were being linked to software and components such as PLCs, allowing them to do jobs traditionally done by servo motors. He relayed the example of an automated gopher at the University of Minnesota's Bell Museum of Natural History, which wanted to bring the natural display to life. They had a budget of $800 set aside for this, and luckily for them Roger Klisch, who owns Machine System Integrators, was able to accomplish this.
Lastly, if you have five minutes to spare, watch the video "Encoder Feedback in Stepper Motor Systems." You will learn some of the benefits obtained by adding an encoder to your stepping motors.
An encoder can enhance performance with its ability to provide stall detection and stall prevention. Stall detection notifies the user, system or machine as soon as a motor stall occurs. This eliminates the uncertainty about whether or not the motor reached its target position. Stall prevention actually eliminates stalls by dynamically controlling the stator current and speed of the motor to maintain torque in all situations.