How does a low refrigerant charge affect a hermetic compressor?

A low refrigerant charge adversely affects the operation of a hermetic compressor, causing the compressor to run at a higher temperature. This occurs because insufficient refrigerant means there is not enough coolant circulating throughout the system. As a result, the compressor works harder to achieve the desired cooling effect, leading to increased heat generation. The lack of adequate refrigerant also results in less efficient heat transfer and can cause the compressor to become overheated. Prolonged operation at higher temperatures can lead to eventual failure of the compressor, making it crucial to maintain the correct refrigerant level for efficient and safe operation.

The other options describe effects that are not characteristic of a low refrigerant charge. For instance, excessive vibrations, while they may be a concern, are more directly related to mechanical issues or imbalances rather than refrigerant levels. Similarly, the compressor does not operate more efficiently or at lower temperatures under a low refrigerant charge; it experiences stress and inefficiency instead.