HOLT Electricians Practice Exam

Article 440 applies to electric-driven air-conditioning and refrigeration equipment with what type of motor compressor?

1. Induction motor

2. Brushless motor

3. Hermetic refrigerant motor compressor

4. Single-phase motor

The correct answer is: Hermetic refrigerant motor compressor

Article 440 of the National Electrical Code (NEC) specifically pertains to electric-driven air-conditioning and refrigeration equipment, and it primarily addresses hermetic refrigerant motor compressors. These compressors are sealed units that contain the motor and compressor components within a single housing, designed to keep the refrigerant contained and prevent leaks. This design is crucial for the efficiency and safe operation of refrigeration systems, as it reduces the risk of refrigerant loss and enhances overall reliability. Understanding the significance of hermetic compressors is essential for electricians because they commonly encounter these systems in residential and commercial HVAC applications. Hermetic compressors are engineered for various refrigerants and often feature safety and operational controls that comply with NEC regulations. The other options, while they may encompass different types of motors associated with refrigeration applications, do not specifically align with the focus of Article 440. Induction motors and brushless motors can be used in various applications, but they do not describe the hermetic nature or the specific applications outlined in Article 440. Single-phase motors pertain to the type of electrical supply but do not inherently address the design and operational characteristics specific to hermetic compressors. Thus, selecting hermetic refrigerant motor compressors aligns perfectly with the requirements and guidelines set forth in Article 440, undersc