Custom Gearmotor: Dual Planetary DC Motor

Featured Product from Groschopp, Inc.

The dual output Permanent Magnet DC (PMDC) Planetary Gearmotor, by Groschopp Inc, drives two hinged arms on an automated surgical table used in orthopedic surgery. It was designed so that two hinged arms could be positionally aligned, and their movement synchronized at all times.

Design Significance

The traditional solution of link chains, belts, and pulleys has a greater margin of operational error and it is significantly more difficult to synchronize the movement and alignment of the two hinged arms. This design provided the desired operational performance, AND it eliminated the need for two separate motors - which are also difficult to synchronize and are a more expensive solution.

Design Innovations

This is a custom designed, high torque, fractional HP PMDC motor with two planetary speed reducers, one on each end, driven by the same motor shaft. Because the same motor drives both outputs there is both mechanical AND electrical "linkage". If two separate motors were used, a more complex common control would be required to achieve the same positioning and synchronized movement. In addition to eliminating the need for two separate motors, this design essentially eliminates the need for a more complex (and expensive) control scheme to provide electrical linkage.

For more award winning motor designs visit Groschopp.

Upload application specs and we will help you find the right solution for your needs. Groschopp offers a full line of standard AC Induction, Permanent Magnet DC, and Brushless DC motors that can be combined with four gearbox styles: Parallel Shaft, Planetary, Right Angle, Right Angle Planetary. Each motor or gearmotor can be modified or built completely custom to meet an application’s requirements. Groschopp Universal motors are custom built based on five standard frame sizes. If you have any questions about the application specs form or any of our products, give us a call at 800-829-4135 or send us an email.


Groschopp, Inc. is a fractional horsepower electric motor and gearmotor manufacturer located in Sioux Center, Iowa. With a full line of PMDC, AC Induction, Universal and Brushless DC motors, and a full line of Parallel Shaft, Planetary, Right Angle Worm and Right Angle Planetary gearboxes, we offer 8,000 standard motor designs and 150,000 motor or gearmotor combinations to fit your specific need. After over 80 years in the industry, it’s safe to say we are knowledgeable and passionate about what we do.