Type M8 Rotary Incremental Actuator

The Moog M8 rotary incremental actuator is a compact, closely integrated design made up of two key elements: a motor, and a harmonic drive speed reducer. The motor is a small angle permanent magnet stepper with a relatively high holding torque. The harmonic drive speed reducer offers a large reduction ratio, high load capability, low weight, zero backlash and relatively high torsional stiffness. Coaxial nesting of the motor and harmonic drive elements allows use of larger and higher capacity output bearings and gives the unit a low-profile geometry.



Key Features:

  • Very compact and closely integrated coaxial design
  • Relatively high holding torque for its size
  • High gear ratio provides fine step resolution
  • Low weight
  • Zero backlash


Parameter Units Basis Data

Output Step Angle

Degrees Standard 0.050, 0.075 or 0.150
Max. Output Step Rate Steps/sec Maximum 600
Backlash Degrees Maximum Zero
Operating Temperature Range °C Maximum -45 to +65
Torsional Stiffness lb‐in/Rad (Nm/Rad)  Minimum 3800 (430)
Bending Stiffness lb‐in/Rad (Nm/Rad)  Minimum 45000 (5084)
Axial Stiffness lb/in (N/m)  Minimum 250000 (43.9 x 106 )
Radial Stiffness lb/in (N/m)  Minimum 130000 (22.8 x 106 )
Output Load Capability Axial lbf (N)  Nominal 158 (700)
Tranverse lbf (N)  Nominal 158 (700)
Output Torque lb‐in (Nm) Minimum 25 (2.82)
Unpowered Holding Torque lb‐in (Nm) Minimum 14 (1.58)
Powered Holding Torque lb‐in (Nm) Minimum 25 (2.82)
Power Watts Maximum 20
Total Assembly Weight lb (Grams) Maximum 0.77 (350)
Winding Type Redundant if Required Redundant if Required 2 or 3 phase

Related Markets


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