One piece of equipment that is subject to severe duty cycles is the electric motor. From cold starts to instaneous full speed production and all types of shock loadings, plus potential electrical surges and challenging external enviromental factors – these factors can all make up a typical duty cycle for an electric motor.

Motor manufacturers have to consider all of these factors and produce a motor that is capable of withstanding them shift after shift. Plant owners, maintenance staff, and plant designers are now starting to realise that within the big picture the total "cost of ownership" does not begin and end with the motor
purchase price.

Many design characteristics influence how good or bad the motor may be but, as designs have improved, so too has the availability of new materials to assist in the longevity of the electric motor. For example there was a time when even timber made up the components of an electric motor (used as slot wedges to ensure windings remained in place). Today leading motor manufacturers use a pre-formed synthetic slot liner to improve and standardise assembly procedures.

Vital components for longevity include the insulation materials used in the manufacture of the motor. WEG, one of the world’s major electric motor manufacturers with an impressive 40-year history, is at the forefront of such technology. From humble beginings in a small city in the south of Brazil to current production exceeding eight million motors per year, WEG today incorporates the latest materials and procedures in its manufacturing plants (in Brazil, Mexico
and Europe).

WEG engineers, who specialise in the design of electrical machines, rely on insulation materials with high temperature resistance. With increasing frequency they depend on the paper insulation of NOMEX. Its 220-degree Celsius thermal class, high mechanical strength, outstanding electrical properties and superior thermal resistance make it an excellent choice in demanding applications. Laminate materials based on NOMEX are frequently used in machines with insulation system thermal classes between 155 to 180 degrees Celsius. WEG has standardised on the use of Nomex laminate for its W21 range of low voltage motors.

According to Jose Reinaldo Cardoso, material analyst at WEG, "The change to NOMEX was made to further enhance the thermal protection and once again improve the quality of the final product. By using NOMEX brand insulation WEG is able to provide reliable and safer products to its clients with a safety margin to ensure a behind the scenes unseen performance when the heat is on."

For more information contact your nearest WEG sales office or return the reader enquiry card.