Motor

Abstract What if…you could make a step motor faster? And quieter? While saving energy?

Introduction The simplicity and low cost of step motors have made them popular in the automation business for decades. Like most technologies, they’ve steadily advanced to better compete with other forms of motion control. Low cost transistors and logic chips enabled manufacturers to build PWM or “chopper” drives that dramatically extended the usable speed range. Then cheap, compact microcontrollers led to microstep drives that provided finer resolution and smoother, quieter motion. Further increases in compute power and advances in algorithms resulted in anti-resonance and electronic damping that further enhanced machine throughput. Ever decreasing chip sizes and increasing efficiency of MOSFET power transistors allowed the drive electronics to be integrated into the motor itself. Integrated step motors now represent one of the highest growth segments of the motion control industry.

The latest exciting development in stepper technology has been the application of low cost, high resolution feedback devices and advanced digital signal processing to close the loop on stepper motion, resulting in the efficient and high performance StepSERVO™ closed loop stepper system. Here we compare the benefits of StepSERVO™ closed loop stepper systems to traditional open loop stepper systems.

Acceleration (higher is better)

Efficiency (higher is better)

Position Error (lower is better)

Heat (lower is better)

Noise (lower is better)

StepSERVO™ Closed Loop vs Open Loop Stepper Systems Performance Indicators

StepSERVO™ closed loop Open loop

2 Copyright 2015 Applied Motion Products, Inc.

Acceleration & Cycle Time The torque curves below show the peak and continuous torque of a StepSERVO™ closed loop stepper system and the useable torque of a typical open loop stepper system.

To compare acceleration rates, equally sized open loop and StepSERVO™ closed loop stepper systems were...