How to reduce risk when using motors in explosive environments?

Are you in a situation in which you operate equipment in an environment that has explosive or potentially explosive materials? If so, you need to take the proper precautions and select equipment that is certified to operate in such an environment. These environments are also known as hazardous locations.

In the United States, we use NFPA 70, also known as the National Electric Code (NEC), to provide definition and guidance for the requirements to provide electric motors in hazardous environments. The NEC classifies these environments as Division 1, or Division 2. A Division 1 location is one in which ignitable concentrations of hazardous materials are present all or some of the time under normal operating conditions.

Globally, there are many national regulations and certification systems with different requirements.  For ABB’s Baldor-Reliance motors, Underwriters Laboratories (U.L.) and the Canadian Standards Association (CSA) are the certifying bodies that approve and label our electric motors for use in Division based hazardous locations per the NEC and C22.1, the Canadian Electric Code.

Electrical and mechanical equipment installed in such locations must be designed and tested to ensure the equipment does not cause arcing, sparking or high temperatures that could provide a source of ignition for such a mix. In addition, a motor shall be able to contain an explosion within the motor if the flammable mixture ignites inside the motor. ABB manufactures Baldor-Reliance explosion-proof motors specifically to meet the tough requirements for these hazardous environments.

Industries such as chemical, oil and gas may come to mind when thinking potentially explosive environments - but surprisingly, there are many other industrial sectors that have potentially explosive atmospheres somewhere in their process. For instance, paper mills, waste water treatment facilities, sawmills and grain handling facilities may have concentrations of gas or dust that may collect in large enough amounts to require an explosion-proof motor.

ABB’s Baldor-Reliance product brand is the market leader in NEMA motors. Our first explosion-proof, or XP, motor was introduced nearly 100 years ago. Today, we continue that legacy with engineering expertise, adherence to industry and safety standards, quality manufacturing and product availability.

When designing and manufacturing an XP motor, there are changes to a standard motor design that need to take place to comply with the requirements of a Division 1 hazardous location. A few things that need to be considered include, but are not limited to:

•   A variety of seal configurations and flame path designs for safety

•   Heavier enclosure materials to contain the pressure of an internal explosion

•   Close machine tolerances to meet the flame path requirements

•   Potted leads that are permanently sealed to create solid barrier

•   UL-listed drains for motors going into high humidity applications

•   Any auxiliary or accessory equipment that is included shall be certified for the location or included in a certified XP enclosure

We apply these to various types of NEMA motors to have a complete lineup of single-phase XP motors, three-phase XP, severe duty XP, drill rig duty XP, close-coupled pump XP, jet pump XP, brake motor XP and more. We also offer submersible pump and DC motors that are explosion proof.

Today, there continues to be an increase in the use of drives (VSDs) for variable-speed operation. VSDs help ensure that motors run according to process demands, help to save energy and improve process output. To run an XP motor on a drive, the motor must be designed, manufactured and certified for use on non-sinusoidal power, and specified for the proper load type and speed range. When run on a drive, a motor will produce additional heat, so the design needs to take this into consideration. Additionally, the non-sinusoidal power will stress the motor’s insulation due to voltage spikes that can be expected. The Baldor-Reliance inverter duty (ID) insulation system is designed to withstand these expected voltage surges in accordance with ANSI/NEMA motor standard MG 1 - 31.4.4.2.

When specifying a Baldor-Reliance XP motor, you can trust that it meets the specifications and demands of your hazardous application. We work with you, applying our know-how and experience to find the best possible solution to fit your needs. From initial design through manufacture, we are committed to building motors that deliver high performance, efficiency and reliability without compromising safety throughout their entire life cycle.

For added safety and peace of mind, the ABB Ability™ Smart Sensor can be mounted to any NEMA framed motor to wirelessly and economically monitor the health and performance of not only the motor - but the entire drive train. These are certified for hazardous locations.

When faced with applying motors in potentially explosive atmospheres, turn to ABB and the Baldor-Reliance brand for XP motors that are built locally, widely available, with the performance and reliability you expect.