Flame Proof Motors

Flame Proof motors are used in hazardous locations usually in chemical, petroleum and gas industries, where the environment may contain gases or inflammable vapours. Electric equipment are notorious for being the source of sparks during switching. This could be catastrophic in areas where inflammable gases are present.

Hazardous areas classified into zones depending on the possibility of the presence of gases and combustible dust-air mixtures.

The following are the classification for hazardous areas

Zone 0, An Explosive atmosphere is continuously

Zone 1, An Explosive atmosphere is present for 1000 hours in a year.

Zone 2, An Explosive atmosphere is present for 10 hours in a year.

Flameproof motors are specially designed so that any explosion which occurs within the motor is contained within the motor frame itself. This prevents any secondary explosion in the surrounding area. The flame-proof motor is specially enclosed within a protective shield which covers the entire motor including the bearings.

Flame proof motors are heavier that motors of similar rating due to the increased weight of the reinforced design of the end shields so as to withstand the impact of an explosion.

Flame proof motors have special arrangements for cooling. Since conventional air circulation is not possible with these motors, special arrangements such as using the internal air to carry heat to the surface of the motor where the heat is transferred to the external air by means of special tubes have been devised.

Another method of cooling is the use of a coolant such as water which circulate in the stator and rotor of the motor. This water is brought to the near the inside of surface of the motor where it is cooled by means of the atmospheric air.

The cooling system ensures the isolation of the internal cooling medium from the external atmospheric air.