Stator Electrical and Functional Testing

• Advanced winding and stator qualification solutions for development, industrialisation and mass production.
• Customisation of winding and stator qualification solutions to meet specific customer requirements.
• Highly effective in identifying latent defects in the production phase that cannot be detected by traditional dielectric strength and surge tests: Partial discharge measurements allow criticalities and hidden defects to be identified during testing before they can affect the reliability of the product at the end customer. For more information, please refer to Technical Note TN148, which illustrates how Partial Discharge measurements during production testing can easily detect defects in windings.
• In the development and industrialisation phase, PDIV (Partial Discharge Inception Voltage) measurement can be used, for example, to:

• Check the quality of copper/aluminium wires or insulating materials from different suppliers, allowing an objective quality-price evaluation and consequently the selection of the optimum solution.
• Optimise process machine parameters in wound stators, such as selecting the correct winding speed, i.e. the highest speed that can be used without compromising the insulation quality of the wire.
• For hairpin stators, verify that the design parameters (e.g. geometries and bending angles) and the manufacturing process (hairpin bending and insertion into the stator) are such that criticality and latent defects are avoided.
• Monitor the impregnation process by measuring the characteristics of the same stator before and after impregnation. For more details on this subject, see Technical Note TN146, which describes tests carried out on 4 windings with different levels of impregnation quality: no impregnation, standard process impregnation, reduced resin quantity impregnation, reduced solidification time impregnation.

• To quantify how the inclusion of a phase separator, the impregnation process or both affect the quality of the winding insulation. This study, in addition to improving product knowledge, is essential to definethe motor Class for the use with inverters, as required by EN60034-18-41. For more information on this subject, see Technical Note TN147.

• During the end of life tests (stator/motor), check the number of hours after which the insulation material begins to show permanent degradation of its insulating properties. The PDIV test makes it possible to anticipate the assessment of material degradation before product failure occurs, making it possible to identify which materials and processes have the worst quality and start degrading earlier. This approach, used by major companies in high-reliability industries, enables more accurate selection of materials, processes and suppliers.

• The LT400 is particularly suitable for laboratory activities and production testing in small batches. It is particularly useful in the development phase to identify and correct non-obvious criticalities that could compromise stator reliability, and in the industrialisation phase to define acceptance thresholds to be applied in production testing.

In addition to ensuring complete stator qualification, the LT400 is equipped with several functions to identify latent defect trigger conditions that could compromise reliability, such as PDIV (Partial Discharge Inception Voltage) measurement.

• The AST family of systems is designed to perform complete testing in the production of windings and stators for electric motors.

Their great flexibility and high level of customisation allow the stator to be qualified according to specific customer requirements. The desired tests and their acceptance thresholds can be configured based on the data collected with the LT400 during the development and industrialisation phases, ensuring consistency in stator qualification from the early stages of development through to series production testing.

Like the LT400, the AST is capable of partial discharge testing.