Magnetic Gears
Pseudo Direct Drive PDD

Installing a magnetic gear artificial lift system

Contactless, high-efficiency, high-torque transmission with inherent overload protection

A magnetic gear uses permanent magnets to transmit torque between an input and output shaft without mechanical contact. Magnetic gears can achieve efficiencies >99% at full load and with much higher part load efficiencies than a mechanical gear. For higher power ratings a magnetic gear will be smaller, lighter and lower cost than a mechanical gear.  Depending on the space available a magnetic gear may be the only viable technology.  Since there is no mechanical contact between the moving parts there is no wear and lubrication is not required. Magnetic gears inherently protect against overloads by harmlessly slipping if an overload torque is applied and automatically and safely re-engaging when the fault torque is removed.

Magnomatics is not developing a range of standard products but is focusing efforts on particular applications where magnetic gears brings particular advantage.  This may be due to space constraints, efficiency or because of the torque fuse capability inherent in a magnetic gear.

First gears are now in licenced production for ZiLift where they are used to drive a pump in a down bore hole oil and gas pumping application.


Measured Gear Efficiency

Magnetic Gear Key Benefits

  • Increased efficiency (>99% at full load and high part load efficiency)
  • High reliability
  • Low maintenance
  • No transmission oil
  • Physical isolation between shafts
  • Transmission through a sealed wall
  • Torque fuse protection
  • Very low acoustic noise and vibration
  • Compliant transmission eliminates drivetrain pulsations

Planetary Gears - Comparison

Magnetic Gear Explained

Magnomatics’ magnetic gear consists of two rings of permanent magnets with a ring of steel pole pieces in between.  These steel pole pieces act as flux paths from each of the rings of magnets.  This has the effect of creating harmonics in the fields produced by each ring of magnets.  By careful selection of pole numbers one can couple to the harmonic field and this creates a gear ratio.  The behaviour of this gear is exactly the same as a mechanical epicyclical gearbox.  One element of the gear is held still whilst the other 2 rotate.  In gear applications we normally hold the outer ring of magnets still.

See Video