MagneGear™ Rotary Magnetic Gear for Turbodrill or PDM Applications

MagneGear™ RMG configured for use with a drilling motor such as a turbodrill, positive displacement motor or air motor.

• Totally sealless
• Totally non-contacting rotating elements
• Force or speed multiplier / reducer
• Wide range of ratios
• Scalable to any size or torque requirement
• Output shaft rotation can be either the same direction or counter rotating to input shaft

The input shaft shown in yellow is the high speed shaft.  You will notice a thru bore in the input shaft to allow drilling fluid flow.  The output shaft to the bit is shown on the left side of the diagram.

An important attribute of a RMG device is the isolation of axial force.  Axial forces, or thrust, exerted on one member are not directly transmitted to the other members of the RMG.  For example, a high axial load from the bit end of a RMG used in a mud motor application would not transfer to the PDM or turbodrill used as the prime mover.

In large diameter applications, high torque densities are achievable through a single stage magnetic gear device.  Torque density of greater than 500 lb/ft per linear foot of gear device is achievable in a 9-5/8" diameter, with a through bore of 2-3/4" for flow.  For smaller diameters, or for higher gear reduction ratios, multiple stages can be utilized.  For example, it is possible to achieve a 1200:1 reduction ration through four stages in a 6-1/2" or smaller diater and still be able to accommodate drilling fluid or production flow.  This makes the MagneGear Rotary Magnetic Gear and MagneGear Linear Magnetic Gear systems the only reduction gear devices that we are aware of that allow access or intervention to devices below the gear system through an open central bore in the reduction gear device.

The smallest practical diameter for downhole application requiring moderate-to-high torque output appears to be 3-1/2" unless no mud flow is required through the ID of the RMG.  With no flow required through the inside of the RMG device, for example if the RMG is needed to run inside a pressure housing on a tool, it can be practically applied in diameters of 2" or less.

For further inquiries, please e-mail us at info@dextermag.com -or- call us at 888-556-5023.