Carick “Joe” Howard
Red Stick Armature Works, Inc.

Es bien conocido por aquellos que trabajan con el almacenamiento de motores eléctricos que las filosofías y procedimientos de mantenimiento varían. La revisión minuciosa de la información de EASA y siete fabricantes de motores diferentes sobre el almacenamiento de motores reveló algunas diferencias y similitudes interesantes en la información disponible en cada una de las fuentes consultadas.

Varias fuentes comparten elementos comunes como el ambiente, la protección contra humedad, el mantenimiento de los rodamientos y la resistencia de aislamiento. Aquí, la finalidad de nuestro debate es describir algunas de las diferencias y ojalá dar a conocer algunos puntos a tener en cuenta cuando se crea un procedimiento de almacenamiento a largo plazo para los usuarios finales.

Storing an electric motor for more than a few weeks involves several steps to ensure it will operate properly when needed. For practical reason's, these are governed by the motor's size and how long it will be out of service. Factors like temperature, humidity and ambient vibration in the storage area also influence the choice of storage methods, some of which may be impractical for smaller machines or need to be reversed before the motor goes into storage. This article covers.

• Keeping good records
• Storage conditions
• Shafts and machined surfaces
• Bearing protection
• Special care for windings
• Carbon brushes

READ THE COMPLETE ARTICLE

Chuck Yung
EASA Senior Technical Support Specialist

When an electric motor is expected to be stored for an appreciable time before it is placed into service, certain steps should be taken to ensure that it will be suitable for operation when it is needed. The practical limitation we need to recognize is that much of what we do when putting a motor into long-term storage has to be undone when the same motor is moved into operation. This article addresses common recommendations for stored motors.

En toda reparación mecánica, la capacidad para desmontar, reparar y volver a montar el motor de forma apropiada sin dañar innecesariamente ninguna de sus piezas es fundamental. Esto suena sencillo, sin embargo, durante el proceso de desarme se cometen demasiados errores costosos.

Si todos los motores entraran “como nuevos”, la tarea sería más simple, aunque esto no sería garantía de que el montaje del motor fuera adecuado.

Cuando un centro de servicio recibe un pago por reparar un equipo, quiere que este permanezca en funcionamiento, ya que, si el equipo falla dentro del período de garantía, deberá asumir el costo de volver a repararlo. Por lo que tiene sentido realizar la reparación correcta la primera vez.

Los procedimientos de reparación, así como los propios motores, son afectados por los cambios en la tecnología. Este libro intenta incluir las últimas tecnologías comprobadas. En muchos casos, los métodos de reparación tradicionales aún pueden ser la alternativa más práctica. Las opciones presentadas a lo largo de este libro están destinadas a ayudar a los técnicos a seleccionar el método de reparación correcto, reconociendo que la decisión final recae en el propietario del equipo.

Algunas veces los métodos de reparación pierden popularidad, no porque aparezcan métodos mejores sino debido a técnicas deficientes. Otros métodos de reparación son adecuados para algunas aplicaciones, pero no para otras. Es trabajo del reparador decidir cuál será el mejor método para cada caso.

Este libro se encuentra dividido en secciones para los componentes básicos del motor con métodos de reparación y consejos dispersos por todas partes. Donde resulte práctico, se discuten también las causas de fallo. Esto ayudará a los técnicos a seleccionar el método de reparación más apropiado para cada aplicación en particular. La información presentada se basa en publicaciones de EASA y en revistas técnicas y literatura suministrada por fabricantes de motores, proveedores y centros de servicio establecidos.

COMPRAR DESCARGAR COMPRAR VERSIÓN IMPRESA

Tabla de contenido

• Terminología del motor
• Aplicaciones del motor y encerramientos
• Procedimientos de inspección y prueba
• Consejos para desmontar motores
• Rodamientos
• Alojamientos de rodamientos, orificios de eje, sellos y ajustes
• Ejes
• Rotores
• Ensamble del motor
• Accesorios y cajas de conexiones del motor
• Dinámica del motor
• Vibración y geometría del motor
• Corrientes por el eje/rodamientos
• Consideraciones especiales para motores a prueba de explosión
• Fallos en las componentes mecánicas
• Reparaciones misceláneas

Esta obra contiene muchas sugerencias sobre el manejo apropiado de las diferentes partes de un motor para minimizar los daños durante el proceso de reparación. Sin embargo, es imposible desarrollar un listado que las incluya todas.

En cambio, el principio básico de tomarse el tiempo para usar la herramienta adecuada y por lo general el procedimiento apropiado guiará a los técnicos por el camino correcto.

This 40-page booklet provides a great marketing tool for your service center! Use it to provide end users with information that will help them obtain the longest, most efficient and cost-effective operation from general and definite purpose electric motors with these characteristics:                                                                                                          

• Three-phase, squirrel-cage induction motors manufactured to NEMA MG 1 standards 
• Power ratings from 1 to 500 hp (1 to 375 kW)                                        
• Speeds of 900 to 3600 rpm (8 to 2 poles) 
• Voltages up to 1000V, 50/60 Hz 
• All standard enclosures (i.e., DP, TEFC, WPI, WPII) 
• Rolling element (ball and roller) and sleeve bearings

This booklet covers topics such as:

• Installation, startup and baseline information
  • Basic system considerations
  • Installation
  • Startup procedures
  • Baseline data
  • Total motor management
• Operational monitoring and maintenance
  • Application specific considerations
  • Preventive, predictive and reliability-based maintenance
  • Inspection and testing
  • Relubrication of bearings
• Motor and baseline installation data
• How to read a motor nameplate
  • Overview
  • Required information
  • Other terms
• Motor storage recommendations
  • Motor storage basics
  • Preparation for storage
  • Periodic maintenance

This resource is provided as a FREE download (use the link below). You can also purchase printed copies ready to distribute to your current or potential new customers. The cover of this booklet can also be imprinted with your company's logo and contact information (minimum order or 200). Contact EASA Customer Service for details.

READ MORE ABOUT THE FEATURES AND BENEFITS

Cyndi Nyberg
Former EASA Technical Support Specialist

Electric motors often use space heaters to prevent condensation inside the motor when it is not running. In damp areas, they may be necessary to prevent condensation from forming on the windings. They are also important for motors that are on “stand-by” equipment, or motors that are out of service for prolonged periods of time. The function of a space heater is to keep the winding temperature 5^o to 10^oC above the ambient temperature.

Another type of space heater is the silicone rubber space heater that is applied directly to the winding end turns. One advantage to this type is that they use less power to heat the windings, and they also remain cool to the touch. It is a good idea to insulate between the heater and the winding. It is possible, although rare, for a faulty heater to cause winding failure.

Chuck Yung
EASA Senior Technical Support Specialist

One of the more mundane things we as repairers must be concerned with is motor storage. For many of us, storing large motors for major customers is its own profit center. For all of us, being aware of how our customers store the motors we repair and send to them is critical to customer satisfaction. A poorly stored motor is likely to suffer winding or bearing failure, and we don’t want unrealistic warranty claims over something outside our control.

Our primary concerns when storing motors, especially long-term, are windings, bearings and shaft sag.

Tom Bishop, P.E., and Chuck Yung
EASA Senior Technical Support Specialists

The typical service center repairs at least 300 motors per technician annually. Saving 8 minutes (0.133 hours) per job equates to: 300 x 0.133 = 40 man-hours per year—a full week of labor per employee. It is not unrealistic to expect twice that much savings, just by implementing some of these timesaving tips.

We all know that seemingly small time savings can significantly improve the bottom line. For a service center with a 12% return on investment (ROI), shaving a few minutes off each job is the equivalent of adding 2 manmonths of billing per productive employee.

For a 10-man service center, with a shop rate of $75 per hour, 20 man-months times 75 = $258,000. To add a quarter-million dollar account usually means adding personnel, sales maintenance, and risk of bad debt/warranty expense. However, steps that streamline efficiency continue to pay dividends.

Topics covered include:

• Layout and workflow
• Time killers
• Time: Is every hour on the job billable?
• Time-saving equipment
• Attitude and productivity
• Communicating effectively
• Training
• Lighting
• Calibration
• Storage/handling/procurement
• Parts storage
• Examples from real service centers

Carick "Joe" Howard
Red Stick Armature Works, Inc.

It is common knowledge to those involved in the electric motor storage business that maintenance philosophies and procedures vary. Thorough reviews of available information on the topic of long-term storage from EASA and seven different motor manufacturers revealed some interesting similarities and differences in the information available from each source.

Several sources share common elements such as environment, moisture protection, bearing maintenance, and insulation resistance. The purpose of our discussion here is to describe some of the differences and hopefully give some points to consider when creating a long-term storage process for end users.

Chuck Yung
Especialista de Sénior de Soporte Técnico de EASA

Una de las cosas más mundanas de las que debemos preocuparnos como reparadores es el almacenamiento de los motores y para muchos, almacenar motores grandes para clientes importantes representa ganancias. Para todos nosotros, ser conscientes de cómo nuestros clientes almacenan los motores que les reparamos es crítico desde el punto de vista de la satisfacción del cliente. Es probable que un motor mal almacenado sufra fallos en el devanado o en los rodamientos, y no queremos reclamos por garantía poco realistas sobre algo que está fuera de nuestro control.

Nuestras principales preocupaciones al almacenar motores, especialmente a largo plazo, son los devanados, los rodamientos y el pandeo del eje.

Chuck Yung
EASA Senior Technical Support Specialist

This webinar recording discusses motor storage and drills down into the nuances of maximizing customer perceived value. There are practical considerations such as cost-effective climate control and using motor storage to obtain more repair work.

• Dewpoint and relative humidity
• Anti-vibration storage
• Bearing protection practices
• Service value

This webinar recording is intended for managers, sales personnel and company owners.

​Este folleto de 40 páginas ofrece una gran herramienta de marketing para su centro de servicio! Lo utilizan para proporcionar a los usuarios finales con información que le ayudará a obtener la, operación más eficiente y rentable de propósito más larga de los motores eléctricos generales y definidas con estas características:

• Trifásica, motores de inducción de jaula de ardilla fabricados con las normas NEMA MG 1
• Los valores de potencia de 1 a 500 CV (1 - 375 kW)
• Velocidades de 900 a 3600 rpm (8 a 2 polos)
• Tensiones de hasta 1000 V, 50/60 Hz
• Todas las cajas estándar (es decir, DP, TEFC, WPI, WPII)
• Rodando elemento (bolas y ruedas) y los cojinetes de manguito

Este folleto cubre temas tales como:

• Instalación, puesta en marcha y la información de base
• monitoreo y mantenimiento operativo
• Datos del motor y la instalación de línea de base
• Cómo leer una placa de identificación del motor
• recomendaciones de almacenamiento del motor

Este recurso se ofrece como una descarga gratuita (utilizar el enlace más abajo). También puede comprar copias impresas listo para distribuir a sus actuales o potenciales nuevos clientes. La portada de este folleto también se puede imprimir con el logotipo e información de contacto de su empresa (pedido mínimo o 200). Póngase en contacto con Servicio al Cliente EASA para más detalles.

This version of Principles of Medium & Large AC Motors manual is now available to address applicable IEC standards and practices. This 360-page manual was developed by industry experts in Europe along with EASA's engineering team. (The "original" version of this book based on NEMA standards remains available as a separate document.)

This manual includes drawings, photos and extensive text and documentation on AC motors, including how they work, information on enclosures, construction on components and applications. Many of the principles included apply to all AC motors, especially those with accessories that are associated with larger machines in the past (such as encoders, RTDs, thermostats, space heaters and vibration sensors).

While the manual covers horizontal and vertical squirrel-cage induction motors in the 37 to 3,700 kW (300 to 5,000 hp) range, low- and medium-voltage, most of the principles covered apply to other sizes as well. 

This valuable instructional/resource manual is available in printed and downloadable versions, and focuses primarily on IEC motors.

Sections in the manual include:
(Download the PDF below for the complete Tables of Contents)

• Motor nomenclature & definitions
• Motor enclosures
• Typical motor applications
• Safety & handling considerations
• Basic motor theory
• Motor standards
• Stators
• Squirrel cage rotors
• Shafts
• Bearings & lubrication
• Motor accessories & terminal boxes
• Test & inspection procedures
• Motor alignment, vibration & noise
• Storage procedures
• Synchronous machines

BUY A COPY FOR YOUR OFFICE

PRINTED BOOK DOWNLOADABLE PDF

This book is also available focusing on NEMA Standards — in both English and Español.

NEMA - English NEMA - Español

Cyndi Nyberg
Former EASA Technical Support Specialist

Many service centers are also motor distributors, keeping a large stock of motors to sell. In addition, many hold motors in storage for specific customers as their spares. Many end users also keep spare motors on site to keep production moving when a motor fails or needs an overhaul. In any of these cases, whether a motor is stored for a month or many years, there are certain steps that must be taken to ensure that as soon as a motor is taken out of storage, it will be in good condition.

Keep in mind that the suggested time periods are not absolute; different environmental conditions might necessitate a different schedule. Also keep in mind that smaller motors may not need the same special attention that a larger or more critical machine will need.

Cyndi Nyberg Esau
Former EASA Technical Support Specialist

Trickle heating is another very practical option to heat AC stator windings or DC field windings while they are not energized. In this method, a low voltage is supplied to the winding. The advantage of trickle heating on a winding is that you are heating the winding somewhat evenly, rather than relying on radiant heat from an "outside" source. In addition, the maximum surface temperature attained is much lower due to the lower watts per square inch of surface area.