NATE Air Conditioning and Heat Pumps Practice Exam 2025 - Free HVAC Certification Practice Questions and Study Guide

Hermetic compressor motors are typically cooled by utilizing the suction vapor drawn from the evaporator. In a refrigeration system, the compressor is designed to compress vapor refrigerant, which is in a low-pressure gaseous state when it enters the compressor. As the vapor moves through the compressor, it absorbs heat from the motor, effectively cooling it. This process allows the compressor to maintain a suitable operating temperature, ensuring efficient performance and longevity.

The suction vapor is critical because it not only provides cooling but also ensures that the refrigerant is in the right state for the compression process. This method of cooling is efficient as it takes advantage of the existing refrigerant cycle, keeping the motor temperature in check without the necessity for additional cooling systems.