Overview
The project objective was to evaluate the reliability of motor winding technologies able to work at high temperatures. To achieve this goal within the time defined in the Clean Sky call sheet, it was necessary to rely on existing technologies, which offer opportunities for rapid implementations on conventional machines, while opening new opportunities towards higher temperatures with innovative technologies.
Three sets of technologies were studied:
- The technologies based on enamelled wires associated to polymer impregnation varnishes.
- Technologies based on wires wrapped with glass fibber associated to impregnations made with epoxy resins.
- The insulation technologies based on ceramics, which offer potential prospects for very high temperatures.
The three sets of technologies were tested for increasing temperatures on representative test vehicles (twisted pairs, transformer coils and motorettes) involving measurement systems able to get the main parameters of the insulation system (DC and AC leakage currents, partial discharge inception voltage, breakdown voltage, …). The analysis of changes in recorded parameters during the test campaigns estimated the maximum permissible temperature in the heart of the winding for each technology. This data, combined with constraints of implementation of each technology defined recommendations for the design of electrical machines able to operate at high temperatures for each selected technology.
The part relating to the use of ceramic insulations opens the way to a major technological leap. With such materials, the maximum operating temperature of electrical machines was no longer be imposed by the winding insulation system but by other parts (magnetic or mechanical), consequently new design methods will have to be developed. It is therefore important to put this new approach against the best we might obtain from other technologies by proposing solutions applicable in the short term.
Funding
Results
Executive Summary:
Reliability assessment of key technologies for high temperature electrical machines
HT° Motor windings (JTI-CS-2011-1-SAGE-02-008)
The project objective was to evaluate the reliability of motor winding technologies able to work at higher temperatures than those currently used in the field of aeronautics or other applications.
To achieve this goal, it was necessary to rely on existing European technologies, which offer opportunities for rapid implementations on conventional machines, while opening new opportunities towards higher temperatures with innovative technologies.
Three sets of technologies were studied:
- The technologies based on enamelled wires associated to polymer impregnation varnishes. These technologies are conventional for small and medium electrical machines that operate at temperatures defined by current standards.
- Technologies based on wires wrapped with glass fibber associated to impregnations made with epoxy resins. These technologies are currently used for large machines.
- The insulation technologies based on ceramics, which offer potential prospects for very high temperatures. However, these technologies will be more difficult to implement in the short term because they require exploratory studies.
The three sets of technologies have been tested for increasing temperatures on representative test vehicles (twisted pairs, and motorettes) involving measurement systems able to get the main parameters of the insulation system (DC and AC leakage currents, partial discharge inception voltage, breakdown voltage,…). The analysis of changes in recorded parameters during the test campaigns were estimate the maximum permissible temperature in the heart of the winding for each technology. These data, combined with constraints of implementation of each technology are defining recommendations for making electrical machines able to operate at high temperatures for each selected technology.
The part relating to the use of ceramic insulations opens the way to a major technological leap. Indeed, with such materials, the maximum operating temperature of electrical machines will no longer be imposed by the winding insulation system but by other parts of the motor (magnetic or mechanical parts), consequently new design methods will have to be developed. It is therefore important to put this new approach against the best we might obtain from other technologies by proposing solutions applicable in the short term.
The three components of the project were estimated of equal importance; the research effort devoted to insulation technologies based on ceramics, which correspond to long-term applications with a major technological leap, is equal to one third of the overall effort.
Finally, the project gave special attention to propose one or more key technologies for high temperature electrical machines for future.