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Epicyclic Gear Systems: Application, Design & Analysis

December 3-5, 2019 | Hilton Garden Inn Downtown Seattle, Seattle, Washington

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Course Outline (pdf) Registration Form (pdf)

Course Description

Learn and define the concept of epicyclic gearing is including some basic history and the differences among simple planetary gear systems, compound planetary gear systems and star drive gear systems. Cover concepts on the arrangement of the individual components including the carrier, sun, planet, ring and star gears and the rigid requirements for the system to perform properly. Critical factors such as load sharing among the planet or star gears, sequential loading, equal planet/star spacing, relations among the numbers of teeth on each element, calculation of the maximum and optimum number of planet/star gears for a specific system will be covered. Provides an in-depth discussion of the methodology by which noise and vibration may be optimized for such systems and load sharing guidelines for planet load sharing.


Classes are 8:00 am - 5:00 pm.

Learning Objectives

Learning Objectives:

  • Restate exactly what makes a gear system an epicyclic system
  • Calculate the total reduction ratio of an epicyclic system and that of a star system.
  • Identify differences and similarities between split power systems and true epicyclic systems.
  • Recognize when the use of a star drive system is preferred over a planetary system.
  • Explain the importance of equal planet/star gear spacing and how a system be designed with unequal planet spacing.
  • Interpret how the numbers of teeth selected for the individual gears in an epicyclic or star drive gear system affect the noise and vibration characteristics of the system.
  • Identify are the advantages of selecting odd numbers of teeth for the planet/star gears?
  • Evaluate the numbers of teeth on the sun, planet and internal ring gear not arbitrary and what are the relations that must be maintained among these tooth numbers and why
  • Explain how the design of the carrier affects the overall performance of these complex systems
  • Determine how does input speed affect the design of an epicyclic system and why are the speed concerns different for epicyclic and star drive systems
  • Restate how the selection of the “fixed” member in a planetary system affect the ratio and relative rotation directions of the input and output shafts?
  • Describe the design and use of load balancing systems including floating sun gears, and floating ring gears.

Continuing Education Units: 2.0

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Cancellation and Payment Policy

Payment must accompany this form. All cancellations must be in writing and received by AGMA 14 days prior to the class start.  A $200 U.S. processing fee will be assessed for each cancelled registration that results in a refund after the 14-day period. A substitution or schedule change fee of $50 when substituting one student for another or moving the current student to another AGMA course after the 14-day period. A 50% refund will be issued if cancellation occurs on or after the class start date.

Hotel Info

Hilton Garden Inn Downtown Seattle
1821 Boren Avenue
Seattle, Washington 98101

Driving Directions

Room Rate

Room Rate


To reserve your room, please click this link.

The deadline to reserve your room is November 4, 2019. We cannot guarentee our room rate after this date.



First Registrant From Company
Additional Registrant From Company


First Registrant From Company
Additional Registrant From Company


Raymond J. Drago, P.E.

Raymond J. Drago is Chief Engineer of Drive Systems Technology, Inc. (DST), a mechanical power transmission consulting organization that he founded in 1976. Prior to this, Mr. Drago worked for the Boeing Company – Helicopters Division until his retirement after 37 years of service. Currently Mr. Drago is involved in the analysis, design, manufacture, assembly, and testing of many gear systems. In his role with DST, Mr. Drago is active in all areas of mechanical power transmission, including the design and analysis of drive systems in a very diverse field of application from heart pumps to very large mining & mill gears. He has also prepared and delivered more than 150 seminars dealing with various aspects of gear design and analysis.

Steve Cymbala

Steve Cymbala has served as Senior Drives Engineer for Drive Systems Technology, Inc. for more than 40 years. In this capacity, Steve performs gearbox design functions as well as client drawing reviews prior to placement of orders. He performs field gearbox failure investigations as well as witnessing various Non-Destructive Examination inspections at gear manufacturing facilities on behalf of DST, Inc. clients. Steve was an employee of the Boeing Company for 34 years where he held a position of Staff Engineer.