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March 2017:


ALXION celebrates its 30th anniversary in 2017. It is an opportunity to take stock of the products and developments that have marked the history of the company until today in the field of permanent magnet synchronous motors for the direct drive of automated axis, alternators for renewable energy generation, and for advanced applications of high power motors.

In 1987, ALXION, supported by ANVAR, the French National Research Valorization Agency, launched its first range of high torque motors for direct drive with hollow shaft, the FC motors, which will find numerous applications internationally thanks to the commercial action of ALXION and its distributors, including VICKERS, which will be subsequently acquired by MOOG.

At the time, the magnets used in the FC motors are ferrites in flux concentration to maximize torque-to-weight performance. ALXION is a pioneer in France and one of the first in Europe in high-torque brushless motors for direct drive.

In order to be able to operate its motors with precise position transducers, hollow shaft precision encoders being not available, ALXION developed resolvers of ± 1 arcminute accuracy with hollow shaft of 90 mm diameter without slipping contacts, the range RESFC , designed with industrial technologies making their cost competitive for industrial applications.

The first applications of the FC motors are in the pneumatic industry, in the glass industry, in the machine tools, in the cardboard printing machines, in the non-woven textile machines, in centrifuges and gyroscopic tables for the aerospace industry.

ALXION continued its developments and developed in the early 1990s the range of 136OEP motors with high power-to-weight, very compact motors allowing to develop 30 KW permanent at 6000 mn-1 and 60 KW during 3 minutes with a mass of only 28 Kg . This very high power-to-weight allows to address newest applications of spindles for extruders carried by articulated arms, which was not possible until then.

In the early 2000s, the rise of high-energy neodymium-iron low-cost magnets combined with the mastership in electro-magnetic simulation softwares enabled ALXION to develop the ST torque motor range with bearings, encoders or resolvers and also frameless STK rotor-stator kits with high torque-to-weight ratio. Again, ALXION is a pioneer in France and one of the first in Europe. Neodymium-iron magnets allow very high diameter hollow through shafts very favorable to the development of direct drive because auxiliary shafts, pipes, cables, manifolds, differentials and gears and related processes can be housed inside the rotor in direct relation to the load.

Until the early 2000s, applications of ALXION torque motors were being developed in the industrial manufacturing workshop environment.

However, as of 2003, STK motor kits will also begin to come out of factories and industrial environment.

Firstly, the extreme compactness of the ALXION STK motors and their reputation for reliability incite manufacturers of small wind turbines from a few hundred watts to 30 KW, mainly for home or agricultural applications, to use STK kits motors in alternators for generating the electric energy in direct drive without multiplier on the shaft of the turbine, thus simplifying the kinematics of the wind turbine to the extreme.
In this case, users more familiarly talk about permanent magnet generator rather than alternator, thus referring to old terms of asynchronous generator or DC generator.

Subsequently, for reasons of compactness, reliability and also quiet operation, the STK kits have been applied in theaters and amusement parks, particularly at Disney for large volumes.

Similarly, applications for the propulsion of underwater vehicles originated at first in sealed envelopes for shallow applications and then the demand also evolved towards applications of high depth up to 500 m with the need to set the internal parts of the motors in the oil under a pressure slightly higher than the external pressure.

Recently, however, the growth of applications of small water turbines up to 30 KW has led manufacturers to focus on the use of STK motors operated in alternators in waterproof envelopes for tidal, wave or river power stations. Often, direct drive rotational speeds, particularly in river applications, are so low that they require a speed multiplier to avoid the use of an extremely high torque and excessively expensive alternator. There is therefore a need for higher speeds for permanent magnet generators.

Indeed, the low-speed direct drive without reduction gear (or speed multiplier) is technically and economically interesting for applications of reduced or average power. As soon as the power becomes high at low speed, the torque required is so high that the permanent magnet motor whose dimensions depend directly on the torque, even if it is optimized in dimensions, becomes very cumbersome and also expensive. This is why, for power ranging from 30 KW to some hundred kilowatts, which correspond in particular to industrial applications for the extrusion of plastic and rubber, as well as in most water turbines, a demand started for so-called semi-direct applications with a high-torque motor running at speeds up to 1500rpm and one reduction stage (or multiplication stage in the case of power generation ), preferably with a planetary gear housed inside the rotor thus allowing a through hollow shaft.

In this way, an advantageous technological compromise is obtained, in particular for higher powers in the industry, which has the main advantages of direct drive without the maintenance and efficiency inconveniences of multi-train gearboxes.

The extension of torque motors and permanent magnet generators applications in outdoor environments on the one hand and with relatively high speeds on the other hand, whereas traditional direct drive applications are at slow speed, led ALXION to various technological developments.

As a matter of fact, the standard rotors of ST complete torque motors and STK frameless torque motor kits have a highly reliable and cost-effective cylindrical glue-bonded magnets structure in efficiently sealed applications of lower speed and especially in workshops with a standard temperature and humidity environment.

For higher speed applications that are susceptible to vibration due to the lack of balancing or incomplete balancing of rotary equipment and for applications in the presence of moisture, ALXION designed and experimented a rotor encapsulation structure encasing the glue bonded magnets with multi-layer peripheral bandage under tensile strength which has proved its reliability on a very large number of cases.

It will be noted that the same technology of rotor encapsulation and peripheral bandage makes it possible to address also the applications of motor internal parts immersed in dielectric oil under equipressure.

More recently, ALXION encountered new applications of permanent magnet torque motors where the presence of glue and polymers was to be avoided mainly in the rotor. These are in particular applications of rotors in vacuum exposed to ionizing radiations and, on the other hand, applications in printing machines where the presence of aggressive solvents such as toluene, penetrating in spite of the sealings in the users’ mechanics can damage the bonding glues and the polymers.

For these applications, a rotor without glue and polymers is either needed or at least recommended, in particular a clamping of the magnets to the rotor provided by mechanical parts without glue. In addition, interchangeability with standard rotors must be maintained to facilitate application maintenance.

ALXION has therefore worked on the design of an adhesive-free rotor made of mechanical parts and interchangeable with standard rotors and has designed and tested a rotor structure that ensures vacuum and ionizing radiation applications and magnets reliable bonding for applications in an aggressive environment.

Thus, ALXION currently has 3 rotors structures that are reliable for different applications and environments:

The standard torque motor or alternator rotor with glue-bonded magnets, suitable for slow speeds in direct drive in dry workshop environments and for well-sealed and non-condensing external applications.

The torque motor or alternator rotor with glue-bonded and encapsulated magnets with peripheral bandage under tensile strength enabling higher speed and / or vibratory applications and / or in the presence of moisture to be addressed. Moreover, this rotor is suitable for applications of motor internal parts immersed in oil under equipressure as in the applications of propulsion of underwater vehicles in deep depth. This rotor is more resistant to external aggressions than the standard rotor but is not immersible in water. Moreover, this rotor is mechanically interchangeable with standard rotors with a slightly higher weight and inertia.

The torque motor rotor without glue and polymers with magnets integrated in mechanical parts. It is intended for applications of rotors in vacuum and ionizing radiations and motors integrated in machines linked to processes with the possibility of infiltration of solvents aggressive for glues despite the sealing.This rotor is interchangeable with the standard rotor and has a slightly higher weight and inertia than the standard one.

Thanks to its policy of constant technological innovation over the past 30 years, subject to rigorous experimentation and systematic industrialization, ALXION has in 2017 a wide range of torque motors and permanent magnet generators for direct or semi- direct drive (with little reduction or multiplication) to address not only the applications of workshops but also a large variety of external applications.

At the end of 2016, ALXION has a population installed on the order of 15,000 motors FC, ST, STK in the world including 1500 alternators for wind turbines and hydro power.

ST and STK torque motors, high power 136OEP motors as well as RESFC resolvers are manufactured in factory ISO 9001 (EN9100) certified.

ALXION sells 55 to 65% of its production according to the years outside France and notably in Europe, China, Canada, and the United States.

ALXION currently produces around 150 motors and alternators per month.

ALXION torque motors are controlled worldwide by most electronic drives available on the market and an application note is available on wwww.alxion.com on this subject.

Among the renowned companies who use ALXION motorss and alternators are:

CERN (Centre Européen pour la Recherche Nucléaire)


March 2017:


February 2017:


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