What are Some Ways that Servomotors Can be Customized for Special Applications?

As experts in customizing servomotors Moog can design and build multiple special features into housed or frameless servomotors that meet the exact needs of special machine applications. One industry where Moog has vast experience designing complex customized servomotors is down hole oil/gas drilling - one of the world’s most demanding applications. In this application, the servomotor designer needs to accommodate high temperature and high-pressure environmental concerns, while creating a custom high performance solution in an extremely small package size.

For over 20 years, Moog has provided a variety of products to the oil drilling industry with a reputation for products that are reliable, high performance and designed to exact application requirement. Some of the primary requirements for down hole oil drilling are solutions that offer high performance, small package size and the ability to withstand tough down hole conditions. We have provided thousands of motors with sizes ranging from 34.9 mm (1.375 in) in diameter to 177.8 mm 7 in. in diameter operating with supply voltages from 24 VDC to over 1000 VDC in ambient temperatures over 200 degrees C (392 degrees F). Demanding environmental conditions we must meet include: 1406 Kg/cm2 (20,000 psi), 220 degrees C (428 degrees F), and 250 G shock. Applications include telemetry, sampling, tractor and directional drilling tools in a variety of applications. Moog provides expert engineering support to ensure easy integration of the customized solution to meet the needs of each of these applications.

New Challenges

Now our down hole drilling customers are challenging us even further with a new technology called HTHP that is increasingly important as new market directives are pushing oil producers further offshore. The acronym HTHP (high temp/high pressure) is synonymous with ultra deep water drilling (water depth over 1,828 Meter (6,000 feet) with actual drilling depths over 6,096 Meter (20,000 feet). This will require even stricter guidelines and new designs to be tested and stretched to their limits. Unbelievable environmental requirements of 2,460 Kg/cm2 (35,000 psi,) 300 degree C (572 degree F), 250 G shock are being placed on our components.

Speed/torque and Physical Size Requirements

  • 34.9 mm (1.375 in.) to 177.8 mm (7 in. diameter) stators
  • Specialized rotors to customer interface
  • Speeds up to and beyond 10,000 rpm
  • Torques over 225 Nm (2,000 lbf in)
  • Voltage ranges from 24V to 1000 volts

In addition, Moog has created designs with increased air gaps and unique construction with specialized materials. Since most of these assemblies are oil filled and efficiency is a critical element, Moog engineers even considers viscous losses in their equations when designing motors.

To meet all of these strict requirements, our design group uses specific processes and quality controls to insure compliance and integrity in these applications. In addition, distinct construction techniques and design guidelines have been developed over time to guarantee manufacturing quality. Even special assembly and test tools were developed for this market.

Moog takes the same approach when designing servomotors for other challenging applications. What we learn in applications such as down-hole drilling can help us when making customized solutions that need smaller package sizes, tight integration and other special features in a variety of machines.


R. Scott Scheffler has over 15 years experience in engineering, systems integration and sales in the motion control industry including the past 4 years as Project Engineer for down hole oil drilling products. He has a B.S. degree in electrical engineering from State University of New York at Buffalo and a Masters of Business Administration degree from St. Bonaventure University.

Tom Cimato has over 40 years of experience designing electromagnetic devices. Since 1983 Tom has been designing Brushless Motors here at Moog along with Design and Project Engineering on various aerospace actuation programs. Tom has continued his education with advanced courses in AC Machines, Brushless DC Motor Design, Permanent Magnets and Control Systems.