Type 3 Rotary Incremental Actuator

The Type 3 actuator is one of our more popular designs, with hundreds of units delivered and successfully operating in space. The standard design is based on the Moog heritage actuator concept, a compact coaxially nested motor and harmonic drive gear system. The most popular version incorporates a potentiometer for position sensing with a redundant three phase motor. As with all Moog actuator products, incorporating optional equipment based on the application is possible. This flexible design can accommodate hard stops, 2 or 3 phase stepper motors, brushless DC motors, a variety of position sensors, cable management systems or other application-specific options. These actuators are commonly used in Antenna Pointing Mechanism applications. The actuators can be incorporated into a biaxial gimbal configuration to fit any application. Contact Moog application engineers for assistance with actuator selection and design options.



Key Features:

  • Compact coaxially nested motor and harmonic drive provides fine resolution
  • Can accommodate 2 and 3 phase motors
  • Low weight
  • Zero backlash
  • Optimized for low power consumption
  • Small angle permanent magnet stepper provides relatively high holding and running torque



Parameter Units Basis                             Data                                 

Output Step Angle

Degrees Standard 0.009375
Steps/Revolution - Standard 38,400
Harmonic Drive ratio - Standard 160:1
Motor Step Angle Degrees Standard 1.5
Max. Output Step Rate Step/Sec (Deg/Sec) Maximum 350 (3.28)
Torsional Stiffness lb-in/rad Typical 140,000
N-m/rad Typical 15,800
Shaft Load Capability Axial lb Maximum 2,500
N Maximum 11,000
Traverse Load Capability lb Maximum 2,100
N Maximum 9,400
Moment Load Capability lb-in Maximum 1800
N-m Maximum 203
Moment Stiffness lb-in/rad Typical 370,000
Power Watts Typical 14
Inertial Capability Kg-m2 Typical 35
High 100
Output Torque lb-in Typical 350
N-m Typical 39.5
Holding Torque: Powered lb-in Typical 500
  Typical 56.5
Holding Torque: Unpowered lb-in Typical 300
N-m Typical 33.9
Total Assembly Weight (with potentiometer) lb Typical 4.2
kg Typical 2

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Moog has designed and manufactured components and systems for satellites and launch vehicles for more than 60 years.

Spacecraft Technologies

Moog is a proven leader in components, subsystems, and systems for spacecraft of all sizes, from smallsats to GEO spacecraft. Moog has been successfully providing spacecraft controls, inspace propulsion, and major subsystems for science, military, and commercial operations for more than 60 years.