Why might recycling or recovery equipment with hermetic compressors overheat when drawing deep vacuums?

The correct answer is that the motor relies on refrigerant flow for cooling. Hermetic compressors are designed to operate in a sealed system where the refrigerant not only performs the work of compression but also serves as a coolant for the motor. When these compressors operate under a deep vacuum, the refrigerant pressure is significantly reduced, which can lead to insufficient refrigerant flow through the compressor. Without adequate refrigerant flow, the cooling effect that is necessary to keep the motor temperature within safe limits is compromised, resulting in overheating.

This phenomenon is significant because overheating can cause motor damage or failure, ultimately leading to the inefficiency or total failure of the recovery or recycling equipment. Proper operation under varying pressure conditions is essential to ensure that the compressor remains within its operational limits and does not overheat due to compromised cooling.

The other options relate to aspects that do not directly impact the compressor's overheating due to insufficient cooling from refrigerant flow. For instance, running faster than other equipment might increase thermal load but does not address the cooling mechanism. A higher compression ratio limit could indicate enhanced performance but also does not explain the relationship between refrigerant flow and motor cooling. Lastly, the burning temperature of oils is not directly related to the cooling provided by refrigerant flow. Thus,