In a welded hermetic compressor, the compressor motor is cooled by which substance?

In a welded hermetic compressor, the compressor motor is cooled by low-pressure vapor refrigerant. This is because the compressor operates by drawing in low-pressure vapor from the evaporator side of the system. As the vapor flows through the compressor, it not only facilitates the compression process but also absorbs heat from the motor.

The low-pressure vapor enters the compressor at a lower temperature, which helps to keep the motor cool during operation. The process ensures that the motor remains within its optimal temperature range, preventing overheating and improving efficiency. The design of hermetic compressors is such that the entire assembly is sealed, minimizing refrigerant loss and allowing for effective heat exchange within the compressor housing.

The other substances listed, such as high-pressure vapor refrigerant, condensed liquid refrigerant, and cooling water, are not utilized for motor cooling in this specific configuration. High-pressure vapor could potentially overheat the motor, condensed liquid is typically in a phase that does not contribute to cooling in this scenario, and while cooling water can be effective in other systems, it's not a standard practice in welded hermetic compressors.