Implementation Considerations for Synchronous Magnetic Torque Couplers (Geometric Misalignment)

Get all the latest magnetic news, resources and success stories right in your inbox:

Filter by category:


Search for keywords:

When selecting a style of Synchronous Magnetic Torque Coupler, one must consider the type and how the coupler will be integrated to ensure a trouble free performance.  The style of coupler, Face-to-Face or Coaxial, will generally be dictated by the requirements of the application, but the ability to ensure correct radial, axial, or angular alignment will also need to be considered.

Each style has tolerance levels for various misalignment conditions.  When the coupler halves are misaligned, there may be no issue, or there could be degradation in the torque transfer to serious mechanical failures.

Each Magnetic Torque Coupler style, Face-to-Face and Coaxial, have somewhat different reactions to the geometric misalignments.

The misalignment conditions are defined as:

Axial Misalignment: The position of each coupler half along the rotational axis of the system.

Magnetic Coaxial Torque Coupler Axial Misalignment Example

Radial Misalignment: The concentricity of the two halves relative to one another.  (The delta between the rotational axes of the two coupler halves.)

face to face torque coupler - example of concentric misalignmentcoaxial torque coupler - example of concentric misalignment

Angular Misalignment: The angle between the rotational axes of the two coupler halves.

face to face torque coupler - example of angular misalignment

coaxial torque coupler - example of angular misalignment

Effects of Geometric Misalignments on Coaxial Style Magnetic Torque Couplers:

Axial Misalignments: (Very Low Impact) –

Coaxial style couplers with an axial misalignment suffer very little impact other than a slight reduction of torque.  As the Coaxial Coupler halves are designed to “nest”, there is an axial force created by the magnetic field to completely align the halves axially.  When there is an axial shift and this axial alignment force is created, it can put some axial load of the system.

Radial Misalignments: (Moderate Impact) –

When the Coaxial Coupler halves have a delta between their rotational axes, one side of the coupler halves is closer than the other.  This creates a radial unbalance which can cause a reduction in torque transfer, vibration, and radial loads. This can negatively impact the mechanicals of the coupler.  (Also, when a Coaxial Coupler is used for instrumentation that requires a sinusoidal output and a radial misalignment exists, distortions of the sinusoidal symmetry can occur.)

Angular Misalignment: (Moderate Impact) –

Like the Radial misalignments, the Angular misalignment creates an unbalance, but it is not symmetric about the rotational axes of the couples.

Effects of Geometric Misalignments on Face-to-Face Magnetic Torque Couplers:

Axial Misalignments (Moderate to High Impact) –

Face-to-Face style couplers are attracting axially, and the net torque transfer capability is a function of the gap between the coupler halves.  If the gap is increased, there is an exponential degradation of the net torque.

Radial Misalignments (Low Impact) –

When the Face-to-Face Coupler halves have a delta between their rotational axes, less magnets overlap, but there are no radial force components created which impact the mechanicals of the system.  There may be a slight torque degradation, but by magnetic coupler standard, the impact is quite low.

Angular Misalignment: (Low to Moderate Impact) –

When a Face-to-Face Torque Coupler has an Angular misalignment, one side of the coupler halves is closer than the other, relative to the working-face.  This may create some mechanical loading and degrade the torque, based on the severity of the misalignment.

In conclusion, the quality of the alignment between any mechanical or magnetic coupler will greatly impact the systems performance.  While Magnetic Torque Couplers are generally more tolerant to mechanical misalignment when compared to conventional mechanical couplers, it is imperative that good integration practices are observed.  Please contact Dura Magnetics for design and integration assistance.


Theory of Operation of a Magnetic Torque Coupler

In the simplest form, magnets are able to exert a force over a distance. Whether by inducing a field in a ferromagnetic material or interacting with another magnet, a magnet can exert a force without touching. The magnet’s magnetic field is the mechanism for this non-contact force...

Read more

Our guide to Magnetic Linear Couplers

In this third Tech Talk article in a five-part series about Magnetic Torque and Magnetic Linear Couplers, we take a closer look at Magnetic Linear Couplers. Similar to a Magnetic Torque Coupler, a Magnetic Linear Coupler relies on the magnetic interaction between two coupler halves. As in the Torque Coupler, usually one half is the driver, and the other half is the follower. Linear Couplers are often simpler to design and to construct when compared to Torque Couplers because the movement is linear and non-rotational...

Read more

Types of Magnetic Torque Couplers – Face-to-Face & Coaxial

In this second post of our blog series exploring magnetic couplers, we examine two different types of the commonly used “synchronous” style of magnetic torque coupler, which is a style of coupler in which the coupler's output shaft speed equals the input shaft speed.  The two primary versions of the synchronous style torque couplers that we will be discussing are the “Face-to-Face” type and the “Coaxial" type.

Read more