Which motor is designed to prevent ignition of the surrounding gas by sparks or explosions within the motor casing?

• A. Electric Motor
• B. Guarded Motor
• C. Explosionproof Motor
• D. Open Motor

Answer: (C)

Explosionproof motors are built to keep any sparks, arcing, or internal explosions contained inside the motor housing, so they cannot ignite the surrounding flammable gas. The enclosure is designed to withstand the pressure of an internal explosion and prevent flame or hot gases from escaping into the outside environment. That's why this type of motor is chosen for hazardous locations where ignitable vapors or gases may be present.

A general electric motor or an open motor lacks such containment, so sparks or hot surfaces could ignite nearby gas. A guarded motor protects personnel from contact with moving parts but does not provide ignition containment for the surrounding environment. In summary, only the explosionproof design is specifically engineered to prevent ignition of the surrounding gas by internal sparks or explosions.