In hazardous work environments, such as oil and gas recovery, chemical and refinery plants, and mining environments, electrical equipment needs to be carefully selected to prevent hazards from occurring, and electric motors are one of them. This article will take you through a detailed look at explosion-proof motors.
Explosion-proof motors are required for industrial applications where highly flammable, prevalent materials are present. Explosion-proof does not mean that a motor will never explode or that it is immune to external explosions. Rather, an explosion-proof motor has features that prevent an internal motor explosion from igniting the larger, surrounding, combustible atmosphere.
Motors can generate an explosion in one of two ways.
1. the surface of the motor becomes so hot during operation that it ignites steam, gas, or dust
2. a single arc from a motor failure (such as a winding insulation failure or power supply problem) ignites surrounding materials.
And explosion-proof motors are designed for use in hazardous environments where flammable gases, dust, or fibers are present. Motors generate heat under normal operating conditions and may spark if the motor coil fails. In environments where specific hazardous materials are present, high motor casing temperatures or sparks that are not properly controlled can also lead to explosions or fires.
Therefore, the use of explosion-proof motors is critical to the safety of your personnel and equipment when operating in hazardous locations.
Motors in Class I environments (UL designation) where flammable gases, vapors, or liquids are present are designed to prevent internal sparks or flames from escaping the motor into the hazardous environment. Explosion-proof motors are designed so that the motor enclosure temperature does not exceed the safe temperature for environments where gases, vapors, or liquids are present.
Explosion-proof motors in Class II or Class III environments (UL designation) where certain dust or fibers are present are designed so that the motor enclosure temperature will not exceed the safe temperature for environments with combustible dust and fibers. While simply running a motor at a lower-rated current can reduce the amount of heat it generates, other failsafe methods of limiting excessive motor case temperatures include thermostats that disconnect power to the motor before it reaches a critical temperature.
If you have any questions, please feel free to contact us for advice.
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