In NFPA 20 practice, which term refers to the general category of a motor defined by mechanical protection and cooling methods?

In NFPA 20 practice, which term refers to the general category of a motor defined by mechanical protection and cooling methods?

• A. Electric Motor
• B. Explosionproof Motor
• C. Open Motor
• D. Totally Enclosed Motor

Answer: (C)

In NFPA 20 practice, motors are grouped by how they’re protected and cooled, which is described by the enclosure type. The general category described here is open motor, meaning the windings aren’t enclosed and cooling is achieved by free air flow. Explosionproof motors and totally enclosed motors are specific enclosure types that provide protection for particular hazardous environments or complete enclosure, but they’re not the broad category defined by cooling method. An electric motor is the device itself, not the enclosure category.

In NFPA 20 practice, motors are grouped by how they’re protected and cooled, which is described by the enclosure type. The general category described here is open motor, meaning the windings aren’t enclosed and cooling is achieved by free air flow. Explosionproof motors and totally enclosed motors are specific enclosure types that provide protection for particular hazardous environments or complete enclosure, but they’re not the broad category defined by cooling method. An electric motor is the device itself, not the enclosure category.