White Paper: Mechanical & Fluid Systems

Direct Drive Motor vs. Rotary Gear Motor


For decades, geared servo motors have been one of the most common tools in the industrial automation toolbox. Offering excellent performance for positioning, velocity matching, electronic camming, winding, tensioning, and tightening applications, geared servo motors efficiently match the power of a servo motor to the load.

This raises the question: Is a geared servo motor the pinnacle of rotary motion technology, or is there a better solution?

In a perfect world, a rotary servo system would have torque and speed ratings that match the application, such that the motor is neither oversized nor undersized. Additionally, the combination of motor, transmission elements, and load should have infinite torsional stiffness and zero backlash. Unfortunately, real world rotary servo systems fall short of this ideal to varying degrees.

This paper examines direct drive motor technology, compares it in terms of cost and performance with that of a rotary gear motor in an application simulation, and identifies the best applications for direct drive motors.

Download now to:

  • Learn about the effects of backlash and torsional stiffness and how they can degrade performance in a servo system.
  • Analyze performance results of a geared servo motor vs. a direct drive motor operating a rotary indexing table under identical conditions.
  • Identify the best applications where you can benefit from the use of direct drive motor technology.

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