Lawrence Livermore National Laboratory

Harmonic Air Motor


Currently available air motors have many advantages over electric motors.

  • More compact
  • Lighter weight
  • Instantly reversible without sparking
  • No heat buildup
  • Undamaged by stalling or overloading
  • Safe in flammable environments
  • Extremely broad torque and speed range

However, generally available commercial air motors have only 5% to 20% of ideal efficiency. By comparison, LLNL's Harmonic Air Motor has all the advantages of air motors listed above, as well as:

  • proven efficiency more than 60% of ideal,
  • higher low-end torque than available commercial air motors, and
  • can be manufactured at lower cost.


LLNL's Harmonic Air Motor uses reed valves, and has a structure nearly identical to conventional, mass-produced, oil-free air compressors. As a result, it can be manufactured inexpensively and with minimal changes to existing production designs. It is ready for mass-market production.


LLNL's Harmonic Air Motor:

  • Can use compressed air at pressures of 80 to 100 psig that are widely available in plants or at remote job sites
  • Is capable of up to 200 psig operation for higher power
  • Has a competitive price, but consumes only 10% to 30% as much compressed air as conventional air motors for equivalent power
  • Harmonic valves reduce moving parts and yield high efficiency
  • Oil free design enables use of exhaust air for cooling or AC purposes
  • Oil free design eliminates need for oil lubrication over its lifetime
  • Has half the weight of conventional air motors of same power
  • Features automatic speed governor to prevent runaway
  • Is compatible with saturated or superheated steam operation

Potential Applications

LLNL's Harmonic Air Motor advantages enable diverse applications such as:

  • Can be used in environments too hazardous for electric motors or internal combustion motors, such as with flammable atmospheres or flammable materials.
  • Hoisting operations benefit by the simple speed control of the Harmonic Air Motor, and the ease of reversing permits accurate control of lifting, lowering and travelling.
  • Can be used for direct drive vehicular propulsion, thus eliminating the need for a transmission.
  • In conjunction with a compressed air storage reservoir, the Harmonic Air Motor, by virtue of its high efficiency, is a viable approach to the storage and recovery of energy originating from intermittent renewable energy sources, such as wind or solar.



Higher efficiency than commercially available air motors

Greater economy of use

Maintains high torque over its entire operating speed range

Enables Direct Drive (transmissionless) applications

Naturally provides a flow of cold air

HVAC applications enabled

Development Status

LLNL's Harmonic Air Motor technology has been proven with multiple prototypes and the intellectual property is covered by both issued and pending patents. The efficiency of this motor has been proven to achieve over 60% of ideal air motor efficiency. High torque is maintained from rest up to full operating speed.