FREE for Members of EASA
Is the motor drawing high no-load amps and winding data are correct? Are you experiencing unusual heating of the stator under load? Those common questions can be answered by checking the stator core condition.
FREE for Members of EASA
¿El motor consume mucha corriente en vacío, aunque los datos del bobinado son correctos? ¿El motor se calienta con carga de forma inusual? Estas son preguntas comunes que pueden ser resueltas verificando la condición del núcleo del estator. En este webinario discutiremos cómo realizar la prueba de lazo en el núcleo de un estator y cómo analizar los resultados obtenidos, proporcionando información sobre los equipos utilizados, consejos para reparar el núcleo del estator y otras pruebas alternativas.
The two primary reasons for performing stator core testing in the service center are (1) to verify that the stator core is acceptable for continued use and in the event of a rewind, and (2) to verify that the repair process has not adversely changed the stator core condition. The purpose of this article is to discuss how we determine, assess and compare stator core test results. It is extremely important to understand that variance in test procedures may invalidate comparison.
Las dos razones principales para realizar la prueba de núcleo del estator en el centro de servicios son (1) verificar que el núcleo del estator es apto para uso continuo y en caso de rebobinado y (2) verificar que el proceso de rebobinado no ha alterado de forma adversa la condición del núcleo del estator. El propósito de este artículo es discutir como determinar, evaluar y comparar los resultados de la prueba de núcleo. Es muy importante comprender que la variación de los procedimientos de prueba puede invalidar la comparación.
Self-paced, interactive training for stators 600 volts or less
This EASA software is a valuable interactive training tool ideal for training your novice(s) ... and even experienced winders will learn from it. The CD teaches how to wind in a richly detailed, step-by-step approach which includes narrative, animations and video clips, with tests to assess student comprehension.
This webinar recording covers:
- Various types of AC motors and bases for operation
- Squirrel cage induction motor rotor design / construction
- Squirrel cage induction motor stator design / construction
We know that excessive temperature and moisture are the largest contributors to bearing and winding failures. Understanding the source of the increased temperature will help us to correct the problem and improve the machine’s life expectancy.
By this time we should all know that stator core loss testing is a required part of a quality rewind. A core loss test before and after burn-off is specified in the EASA Recommended Practice for the Repair of Rotating Electrical Apparatus (ANSI/EASA AR100) and The Effect of Repair/Rewinding on Motor Efficiency; EASA/AEMT Rewind Study and Good Practice Guide to Maintain Motor Efficiency.
Topics covered in this article include:
- Lessons learned
- Rebates add incentive
- Learning from other members
- Determining if the core is usable
- Accurate iron measurements
The challenge for every motor repair firm is twofold: to repair the equipment properly, and to demonstrate to their customers by means of adequate testing and documentation that rewound motors retain their operating efficiency. Following the guidelines in this document will help you accomplish both.
To ensure that motors retain their efficiencies when rewound, EASA also strongly recommends that electric motor repair centers comply with ANSI/EASA Standard AR100: Recommended Practice For The Repair Of Rotating Electrical Apparatus and strictly adhere to the “DOs” and “DON’Ts” presented in this article. These guidelines, which contain safe values (based on available data) and correct procedures, apply to both energy efficient and standard motors. Further study of the matter continues, and these guidelines will be revised if additional information warrants.
Most rotor, stator and armature laminations used in industrial electric motors and generators are made from non-oriented, cold-rolled electrical steels. However, there is a lot of variation in the specific properties in these electrical steels. This article will discuss properties of electrical steels, as well as the methods used to optimize the magnetic characteristics of the laminations, specifically through the annealing process.