Which of the following is NOT a problem associated with excessive superheat?

Excessive superheat refers to the condition in a refrigeration cycle where the refrigerant vapor is heated beyond its saturation temperature, after it has evaporated. Among the listed options, the statement that excessive superheat increases compressor capacity is correct, as it generally indicates that the refrigerant is fully vaporized and the compressor can handle more mass flow of refrigerant, thus providing more capacity. A proper amount of superheat ensures that no liquid refrigerant enters the compressor, which is essential for preventing damage.

In the context of other issues associated with excessive superheat, it indeed reduces the efficiency of the refrigeration machine because the compressor has to work harder to compress the hotter vapor, which results in more energy consumption. Additionally, excessive superheat can lead to compressor overheating because hotter gas entering the compressor can cause it to run at elevated temperatures, potentially damaging the internal components. Lastly, it can also lead to lower cooling output since more energy is being used to compress superheated vapor rather than effectively transferring heat within the system.

Thus, while excessive superheat can have detrimental effects on efficiency, cooling output, and the risk of overheating, it does not characterize an increase in compressor capacity, which is why that is the correct answer in this context.