Which motor is designed to withstand an internal explosion of a specified gas or vapor and prevent ignition of the surrounding gas?

Which motor is designed to withstand an internal explosion of a specified gas or vapor and prevent ignition of the surrounding gas?

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

Answer: (B)

Explosionproof design is what this question is testing. An explosionproof motor has a rugged enclosure strong enough to withstand an internal explosion and, crucially, prevents any flame or hot gases from escaping to ignite the surrounding flammable gas or vapor. The enclosure is built with minimal and carefully arranged openings, flame-arresting paths, and sealing so that even if an internal arc or explosion occurs, the exterior remains safe. This type of motor is chosen for hazardous locations where vapors or gases are present, aligning with classifications in fire pump installations to prevent ignition of the environment. A general electric motor lacks that specialized enclosure, a guarded motor merely protects the moving parts from physical contact, and an open motor exposes moving parts and offers little to no protection against ignition in hazardous atmospheres.

Explosionproof design is what this question is testing. An explosionproof motor has a rugged enclosure strong enough to withstand an internal explosion and, crucially, prevents any flame or hot gases from escaping to ignite the surrounding flammable gas or vapor. The enclosure is built with minimal and carefully arranged openings, flame-arresting paths, and sealing so that even if an internal arc or explosion occurs, the exterior remains safe.

This type of motor is chosen for hazardous locations where vapors or gases are present, aligning with classifications in fire pump installations to prevent ignition of the environment. A general electric motor lacks that specialized enclosure, a guarded motor merely protects the moving parts from physical contact, and an open motor exposes moving parts and offers little to no protection against ignition in hazardous atmospheres.