From the manufacturer’s perspective, a random-wound, 2300-volt motor represents a substantial reduction in manufacturing cost. For the service center, the challenge is to successfully rewind them while providing a reliable repair. Here are some techniques which will enhance your success rate.

Desde la perspectiva del fabricante, un motor de 2300 voltios con bobinado aleatorio representa una reducción sustancial en el costo de fabricación. Para el centro de servicio, el reto es rebobinarlos con éxito y ofrecer una reparación confiable. Aquí hay algunas técnicas que mejorarán su tasa de éxito.

The insulation system chosen for any rewind should be suitable for the application, the voltage class, and the winding process capability of the service center. In most cases, adherence to “equal to or better than” selection is a good practice.

El sistema de aislamiento escogido para cualquier rebobinado debe ser el adecuado para la aplicación, el voltaje y la capacidad del proceso de rebobinado del centro de servicio. En la mayoría de los casos, seleccionar una opción "igual o mejor" es una buena práctica.

Choosing an appropriate lead wire for a new stator winding is an important task. The manufacturer’s information is not always available, or the number of circuits or external connection may have been changed, requiring a redesign of the lead wire.  

Relevant standards including IEC 60085 and IEEE 1 have similar definitions for electrical insulating materials (EIM) and electrical insulation systems (EIS). As with any system, there is an interaction between the materials used, and the insulation system developers take great care to ensure that this interaction does not lead to undesirable outcomes.

Diferentes normas relevantes incluyendo la IEC 60085 y la IEEE 1 definen de forma similar los materiales electro aislantes (EIM) y los sistemas de aislamiento eléctrico (EIS). Como en cualquier sistema, existe una interacción entre los materiales usados y los diseñadores de los sistemas de aislamiento cuidan todos los detalles para evitar que esta interacción produzca resultados indeseados.

This webinar recording shares some of the “best practice” rewind methods used by (and learned from) EASA service centers around the world: connection recognition, best insulating materials, wire choices and tips to save time and effort.

Most modern rotating electric machines operate on the same principles their predecessors have for 100+ years. However, improvements in materials technology over that time have allowed for increasingly greater power density in machine design.

This paper, presented at the EASA Convention 2018, explores advancements in insulation technology and their implications for the repair market. The primary function of stator winding insulation systems is to transfer heat away from conductors, provide electrical insulation, withstand environmental conditions, and minimize vibration. Insulation materials are classified based on their resistivity, with conductors having low resistivity and insulators having high resistivity.