Magnetic couplings

A permanent-magnet synchronous coupling is a special type of coupling based on permanent magnets. It enables contactless, synchronised transmission of torque between two shafts, without mechanical contact or friction. The magnets are arranged in such a way that they generate a common magnetic field, causing the shafts to rotate at exactly the same rate. This contactless transmission makes it an extremely reliable solution, particularly in demanding industrial applications.

Metau magnetic couplings are available with neodymium (Ne) magnets, offering a torque range of 9.4 to 711 Nm, and alternatively with samarium-cobalt (SmCo) magnets for a range of 6 to 474 Nm. Magnetic couplings with neodymium magnets can be used at temperatures of up to 150°C, whilst those with samarium-cobalt magnets can be used at temperatures of up to 300°C.

Depending on the required compressive strength, chemical resistance and the need for the lowest possible or no eddy current losses, various materials are available for the split housing. You can choose between stainless steel, titanium and technopolymer (PEEK).
Metau magnetic couplings can also be supplied in compliance with ATEX.

The permanent-magnet synchronous coupling is an innovative technology based on the principle of contactless magnetic force transmission. It enables a precise and maintenance-free connection between two shafts without the need for mechanical contact or friction.

Design and components:
Inside the coupling there are two main components: the drive side (primary side) and the driven side (secondary side). Both sides are fitted with permanent magnets, which are strategically arranged to generate a combined magnetic field. The magnets are positioned so that they attract each other and form a stable connection when the shafts rotate.

Magnetic field and synchronisation:
The permanent magnets on both sides are aligned in such a way that they generate a synchronous magnetic field. This means that the magnetic poles are arranged so that they attract one another when the shafts rotate at the same rate. This magnetic field acts as an invisible bridge, transmitting the rotational movement from the drive shaft to the output shaft.

Contactless torque transmission:
When the drive shaft is set in motion, the permanent magnets generate a magnetic field that causes the output shaft to rotate. As there is no mechanical contact, there is no friction and no parts subject to wear. Power is transmitted solely via the magnetic field, which makes the coupling extremely low-maintenance.

Automatic synchronisation:
A key advantage is the coupling’s ability to synchronise the shafts precisely. The magnetic field ensures that the rotational speeds of both shafts always match. Should the output side be slowed down or accelerated by external factors, the magnetic field automatically adjusts to ensure precise synchronisation.

Disengagement in the event of overload:
In the event of an overload or blockage, the coupling can disengage automatically. This means that the magnetic fields separate to prevent damage to the system. As soon as the load returns to the normal range, the coupling re-establishes the connection – all contact-free and without any mechanical intervention.

Magnetic couplings offer a wide range of advantages that make them a preferred solution in industrial drive technology:

• • Contactless power transmission: As there are no mechanical contacts, magnetic couplings are wear-free and require virtually no maintenance. This significantly extends the service life of your equipment.

  • Low-maintenance and durable: Thanks to contactless operation, there is no need for wear parts such as shaft seals, mechanical seals, packing and coupling stars, which significantly reduces maintenance costs.

  • Vibration and shock absorption: Magnetic couplings can effectively absorb vibrations and shocks, thereby extending the service life of the entire drive unit.

  • Corrosion resistance: Magnetic couplings are ideal, particularly in corrosive or damp environments, as they are hermetically sealed and have no mechanical contacts.

  • Various designs: Magnetic couplings are available in a range of sizes and designs to meet the specific requirements of different industries.

  • Leak-free pumping: Pumps fitted with magnetic couplings are hermetically sealed. This ensures that a fluid can be pumped without any leakage.

  • Hermetic separation: A magnetic coupling ensures a hermetic seal between the input and output sides. In harsh environmental conditions, such as those found in autoclaves, the drive motor must, depending on the design, be located outside the autoclave, whilst only the driven fan is exposed to high temperatures and high pressure inside the autoclave. The magnetic coupling separates the internal and external spaces from one another, whilst still enabling reliable torque transmission.

The technology behind permanent-magnet synchronous couplings is undergoing a dynamic process of development, driven by advances in materials science, electronics and manufacturing technologies. Listed below are some exciting trends and innovations that could shape the future of this innovative coupling technology:

Use of advanced magnetic materials:
The development of new, higher-performance magnetic materials, such as high-performance NdFeB magnets, enables even stronger magnetic fields to be generated within a smaller installation space. This results in more compact, more efficient couplings with higher torque and better temperature resistance.

Integration of sensor technology and the IoT:
Future permanent-magnet synchronous couplings could be fitted with integrated sensors that provide real-time data on temperature, magnetic field strength, wear or overload. Connectivity via the Internet of Things (IoT) enables maintenance intervals to be optimised, faults to be detected at an early stage and plant availability to be increased.

Improved energy efficiency and environmental friendliness:
With a focus on sustainable technologies, future couplings will be designed to be even more energy-efficient. Through the use of more environmentally friendly materials and optimised manufacturing techniques, resource consumption and the carbon footprint can be further reduced.

Erweiterte Anwendungsbereiche:
Innovationen könnten die dauermagnetische Synchronkupplung in neue Branchen und Anwendungen bringen, beispielsweise in der Medizintechnik, Luft- und Raumfahrt oder in der erneuerbaren Energie. Besonders in Bereichen, die hohe Präzision, Zuverlässigkeit und geringe Wartung erfordern, werden diese Kupplungen zunehmend gefragt sein.

Automation and intelligent control:
By combining advanced control technology with artificial intelligence (AI), couplings could become even more intelligent in the future. They could react autonomously to fluctuations in load, adapt optimally to changing operating conditions and thus further enhance efficiency and safety.

Miniaturisation and integration into complex systems:
Advances in microfabrication are enabling ever smaller designs. This means that permanent-magnet synchronous couplings can be integrated into highly complex, space-saving systems, such as in miniature robotics or portable medical devices.

Opting for magnetic couplings offers numerous benefits that make your systems more efficient, longer-lasting and require less maintenance. Here are a few reasons why this technology is the right choice:

• • High reliability: Thanks to their contactless operation, magnetic couplings are virtually wear-free and offer a long service life.

  • Low maintenance: Fewer moving parts mean less maintenance and lower running costs.

  • Environmentally friendly: As there are no mechanical friction components subject to wear, magnetic couplings are environmentally friendly and sustainable. Thanks to the contactless power transmission, the input and output sides can be hermetically sealed off from one another. Environmentally harmful substances can be pumped without leakage using a magnetically coupled pump.

  • Versatility: They are available in various designs and can be integrated into a wide range of applications.

• • Food and drink industry: For hygienic, wear-free and contactless drive solutions that meet high cleanliness requirements. Magnetic couplings are hermetically sealed and prevent contamination, making them ideal for processing and packaging. In the food industry, for example, magnetic couplings are used in magnetic stirrers.

  • Chemical industry: Magnetic couplings are used in chemical production because they can safely transfer corrosive media. Thanks to their hermetic seal, they protect against leaks and corrosion, thereby enhancing the safety and longevity of the plant. In the chemical industry, magnetic couplings are primarily used in pumps for shaft sealing and power transmission.

  • Pharmaceutical production: This sector requires precise, hygienic and reliable drive systems. Magnetic couplings ensure contactless power transmission that meets high purity standards and facilitates easy cleaning.

  • Automation technology: In conveyor systems, packaging machines, robotics and other automated systems, magnetic couplings ensure wear-free, precise and low-maintenance power transmission. They are ideal for applications where a contactless connection is required.

  • Power generation: In wind turbines, generators and other power generation systems, magnetic couplings ensure the efficient and reliable transmission of torque, particularly in environments subject to high loads or extreme conditions.

  • Medical devices: Owing to their hygienic properties and contactless transmission, magnetic couplings are also used in medical devices where a sterile environment must be maintained.

  • Mechanical engineering: There are a wide variety of applications in mechanical engineering. Magnetic couplings, for example, are used for contactless power transmission in fans for use in autoclaves or in compressors.

Magnetic couplings are an innovative, reliable and low-maintenance technology that demonstrates its strengths across numerous industries. Thanks to their contactless power transmission, they offer protection against wear, overload and corrosion, making them an extremely durable and low-maintenance solution. Magnetic couplings are particularly impressive in demanding applications where precise and safe power transmission is required, thanks to their high efficiency and flexibility. They enable contactless torque transmission, which means there are no mechanical wear parts that need to be regularly maintained or replaced. This leads to significant cost savings during operation as well as increased plant availability.

Furthermore, magnetic couplings offer excellent protection against overload and unwanted feedback effects on the drive system. In the event of sudden faults or blockages, the coupling can disengage automatically, thereby preventing damage to motors or other components. The contactless transmission also ensures virtually wear-free operation, which significantly extends the service life of the components.

They are available in various sizes and designs, making them suitable for both small and large power ranges. They can also be fitted with additional features such as temperature monitoring or remote control to make operation even safer and more efficient.

Given the increasing demands for efficiency, reliability and sustainability in industry, magnetic couplings represent a future-proof solution. They help to minimise maintenance requirements, reduce operating costs and extend the service life of plant. Overall, magnetic couplings therefore represent an innovative technology that paves the way for modern, sustainable drive systems and will play an important role in many sectors – be it in the food industry, medical technology, the chemical industry or energy generation.