The information in this article provides comparisons of key characteristics of IEC and NEMA motors to aid in evaluating the potential simplicity or complexity of the IEC to NEMA design conversion.

La información de este artículo proporciona comparaciones de las características clave de los motores IEC y NEMA para ayudar a evaluar la posible simplicidad o complejidad de la conversión de diseño IEC a NEMA.

When we consider putting a machine into service, we must consider the duty rating of the machine. If we do not, there is a good chance that the machine being placed into service will have thermal degradation of the windings. Not every application is created equal.

Cuando consideremos la puesta en servicio de una máquina, debemos tener en cuenta su tipo de servicio. Si no lo hacemos, es muy probable que la máquina sufra una degradación térmica de los devanados. Sin embargo, no todas las aplicaciones son iguales. 

Customers sometimes send in a motor with no nameplate, or an illegible nameplate, having little knowledge of the machine’s ratings. This article will explore the process of evaluating the machine using frame size, winding data and test data to assign reasonable ratings.

Whether you're selecting a motor for a new application or a replacement for one that has failed, you need a reliable way to match the capabilities and performance characteristics of various motors with the requirements of the application.

The most frequent concern about high current with a three-phase motor is high no-load current. But the broad issue of high no-load current isn’t the only three-phase motor issue to which plants should pay heed.

Too often, replacement specifications for three-phase squirrel-cage induction motors cover only basic nameplate data such as power, speed, voltage, and frame size, while overlooking other important performance characteristics such as the design letter. This can lead to misapplication of a motor, causing poor performance, inoperability, or failures that result in unnecessary downtime.

Process downtime is expensive—even more so when it’s unexpected. So, when an electric motor fails, we tend to pull, repair, or replace it, and move on as quickly as possible. In doing so, however, we may miss an opportunity to capture basic information that could help improve the reliability of the application. With a little planning, these data can be gathered with no delay in startup.

Manufacturers deploy various external connection schemes to produce three-phase induction motors for multiple voltages and/or starting methods. Be sure to follow the relevant connection diagram, which is usually affixed to the motor or contained in its manual. If the diagram is lost, damaged, or ignored, you could find yourself dealing with a costly rewind.