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Implementation carbon fibres for rotor of high speed rotating electric machine

Final Report Summary - HIGHPSLEEVE (Implementation carbon fibres for rotor of high speed rotating electric machine)

Executive Summary:
The objective of the project HIGHPSLEEVE is to develop an innovative rotating composite sleeve to be assembled in an electrical motor by Topic Manager

Reducing specific fuel consumption is a real challenge for future aircrafts. This can be achieved by means of increasing the performance of different systems, such as electrical motors and the associated weight reduction.

The performance improvement means to increase the rotational speed of electrical motors to diminish the dimensions for a given power, but has a drawback which is the limitation in using metal sleeve to keep the permanent magnets in place.

The need for a composite sleeve also could help in the second goal which is weight reduction, but this will depend on other constraints such as working speed and assembly needs.

The aim of the project is to study and manufacture a specific sleeve of an electrical machine with some of the following characteristics:

• To meet a specific air gap condition:

• To meet tolerances expected for the fixation’s thickness
• Uses of metal parts on the sleeve must be reduced, but this will depend on the specific electrical machine on which the sleeve will be assembled (in example: permanent magnet or salient poles rotor)
• Tithing to the rotor has to be done by the fixation itself in case of permanent magnet or with an assembly system in case of salient poles rotor
• Pressure of fixation on magnet, for rotating speeds of 50.000 rpm, has to be in range of beyond 100 MPa, for -50 to 250 ºC.
• Also similar values of pressure and temperature range but speed of 30.000 rpm will be looked for salient pole rotors.

Also, the attachment of the sleeve to the electrical engine will be studied; finally, some prototypes will be manufactured and tested.

To achieve these goals, the HIGHPSLEEVE project will address through the different workpackages in which the project is divided, the following main activities:

• Review of requirement received from Topic Manager = WP1
• Manufacturing process selection = WP1
• Material selection = WP1
• Definition of a text matrix to obtain material properties for design = WP1

• Testing of material = WP1
• Detailed design of the sleeve = WP1
• Detailed design of assembly system = WP1

• Manufacturing of prototypes sleeve in a first run manufacturing trials = WP2
• Testing of sleeve of first run = WP2
• Manufacturing of sleeves in a second run = WP2
• Testing on speed test bench = WP2

• Conclusions of the feasibility = WP2
In the provision of the requirement document the Topic Manager needed to better focus sleeve feasibility in four different cases, two dedicated to a salient poles rotor and two dedicated to a Exitatrice rotor, rather than the one proposed at the call which was one case of permanent magnet rotor.
This new interest makes the project to address to different manufacturing process than initially foreseen for a permanent magnet sleeve.
Also the need to design four different cases in parallel vs one foreseen for the initial interest has made the design phase longer than expected, also due to this new development needed a more complex assembly solution which will include an assembly fixture to achieve the sleeve onto the rotor.

Project Context and Objectives:
The objective of the project HIGHPSLEEVE is to develop an innovative rotating composite sleeve to be assembled in an electrical motor by Topic Manager

Reducing specific fuel consumption is a real challenge for future aircrafts. This can be achieved by means of increasing the performance of different systems, such as electrical motors and the associated weight reduction.

The performance improvement means to increase the rotational speed of electrical motors to diminish the dimensions for a given power, but has a drawback which is the limitation in using metal sleeve to keep the permanent magnets in place.

The need for a composite sleeve also could help in the second goal which is weight reduction, but this will depend on other constraints such as working speed and assembly needs.

The aim of the project is to study and manufacture a specific sleeve of an electrical machine with some of the following characteristics:

• To meet a specific air gap condition:

• To meet tolerances expected for the fixation’s thickness
• Uses of metal parts on the sleeve must be reduced, but this will depend on the specific electrical machine on which the sleeve will be assembled (in example: permanent magnet or salient poles rotor)
• Tithing to the rotor has to be done by the fixation itself in case of permanent magnet or with an assembly system in case of salient poles rotor
• Pressure of fixation on magnet, for rotating speeds of 50.000 rpm, has to be in range of beyond 100 MPa, for -50 to 250 ºC.
• Also similar values of pressure and temperature range but speed of 30.000 rpm will be looked for salient pole rotors.

Also, the attachment of the sleeve to the electrical engine will be studied; finally, some prototypes will be manufactured and tested.

To achieve these goals, the HIGHPSLEEVE project will address through the different workpackages in which the project is divided, the following main activities:

• Review of requirement received from Topic Manager = WP1
• Manufacturing process selection = WP1
• Material selection = WP1
• Definition of a text matrix to obtain material properties for design = WP1

• Testing of material = WP1
• Detailed design of the sleeve = WP1
• Detailed design of assembly system = WP1

• Manufacturing of prototypes sleeve in a first run manufacturing trials = WP2
• Testing of sleeve of first run = WP2
• Manufacturing of sleeves in a second run = WP2
• Testing on speed test bench = WP2

• Conclusions of the feasibility = WP2
In the provision of the requirement document the Topic Manager needed to better focus sleeve feasibility in four different cases, two dedicated to a salient poles rotor and two dedicated to a Exitatrice rotor, rather than the one proposed at the call which was one case of permanent magnet rotor.
This new interest makes the project to address to different manufacturing process than initially foreseen for a permanent magnet sleeve.
Also the need to design four different cases in parallel vs one foreseen for the initial interest has made the design phase longer than expected, also due to this new development needed a more complex assembly solution which will include an assembly fixture to achieve the sleeve onto the rotor.

Project Results:
The main work performed during the project is resumed as follows:
• Material and process selection
As result of the previous activity the “wrapping” technology was selected and due to the wide temperature range of work -55 to 250ºC a high temperature resin prepreg carbon fiber made was as well selected. The most relevant property of the selected resin was its very high Tg and it was complemented by a CF reinforcement.
The selected shape of material is prepreg rolls.
• Test matrix definition
The main goal of the defined Test Matrix was to get some mechanical properties in the extreme temperatures such as -55 and 250º range, to assess the material selected. The properties in other ranges were already tested by the consortium. As well some oil ageing test were defined in order to see its influence in the material properties.
• Material testing for design
Panels were manufactured to carry out proposed material testing. Since the “wrapping” process delivers similar properties than SQRTM process, this is the one that was used to produce testing panels. From this panels specimens were extracted for testing and the tests defined in the test matrix were carried out in oder to get material properties for design.
• Design and analysis
Loops of calculation were carried out, based on existing material data and with the use of KDF to calculate in the range of -55 and 250ºC. After, with incorporation of material properties from testing, final loops were carried out
The design activities focused on the mechanical design of the sleeve as well as, the design of assembly system. Four different cases were analysed in parallel on the first instances of the project The main activities were definition of the different load cases as presented in the requirement document and definition and application of needed constraints in order to evaluate the design performance to get the right layup for the sleeve, carry out 3D CAD work, production of FE model and carry out FE analysis.
The late arrival of the requirement documents, mainly due to change of configurations to be studied involved a change in the project plan that took the final design to be achieved in second quarter of 2016.
• Manufacturing of sleeve
Following the final design and the selected manufacturing process (wrapping) two sleeve tubes were produced and cut to the final dimension of the sleeves.
• Assembly components manufacturing
In parallel with sleeve manufacturing, as well manufacturing of components needed for the assembly of the sleeve onto rotor was carried out.
• Assembly fixture
Since the new sleeve cannot be assembled without help of an assembly system, it has been also carried out the manufacturing of all elements related to an assembly fixture that will allow the final operation of assembly of the sleeve.

Potential Impact:
As well the expected impacts are:
• Pave the way for future development of lower size of the electrical machines where the sleeve is used for the same speed range with lower weight, as well as for higher speed rotors.
• To make possible the increase of the speed for same electrical machine, due to higher specific strength of the sleeve vs metallic materials counterpart.
• Use of best cost effective technology for this specific application.

List of Websites:
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