Large AC motors for hazardous locations

26th September 2019

A new range of alternating current (AC) National Electrical Manufacturers Association (NEMA) electric motors has been launched.

The motors promise an average of 15% more power over conventional designs and meet American Petroleum Institute 541 and 547 standards for motors operating in the oil and gas industry.

The AXR 5000 and 5800 Large AC NEMA motors from ABB offer more horsepower per pound than conventional totally enclosed fan cooled motors (TEFC) but with a smaller frame size in some power ratings.

The smaller frames help save space, up to 8 inches in overall length in some cases, which allows for more compact installations on oil platforms and in refineries.

The motors also offer improved cooling, which could contribute to extending the life of the motor. An internal cooling loop circulates air inside the motor, moving heat to the frame. An external fan blows air over the frame to remove the heat.

The company states that the new cooling configuration offers a more thermally equalized motor, eliminating hot spots that are sometimes evident in TEFC motors. Improved cooling could reduce thermal stresses on the insulation system and may help improve the motor’s longevity.

The main terminal box and auxiliary box can be mounted in several positions, facilitating installation and maintenance and potentially reducing costs.

The rigid frame is designed to increase stability, in order to meet American Petroleum Institute vibration limit specifications.

In addition, the motors feature sleeve bearings that operate at cooler temperatures, with the aim of facilitating maintenance and extending operating life.

The motors are available with a rating of up to IP56, for protection against contaminates and dust ingress.