Final answer:
The oil safety control operates by monitoring the differential between oil pressure and discharge pressure to protect compressors in refrigeration and air-conditioning systems from failure due to inadequate lubrication.
Step-by-step explanation:
The correct answer is option B. oil pressure and discharge pressure. An oil safety control is designed to protect a compressor in refrigeration and air-conditioning systems by monitoring the difference between the oil pressure and the discharge pressure of the compressor. If the oil pressure falls too low relative to the discharge pressure, it indicates that the lubrication within the compressor could be inadequate, which can lead to compressor failure. In such a case, the oil safety control would shut off the compressor to prevent damage. This safety mechanism is critical for maintaining the longevity and efficiency of refrigeration and air-conditioning equipment.
The differential pressure switch monitors the difference in pressure between the oil pressure and the discharge pressure. It is designed to detect any abnormal conditions such as low oil pressure or high discharge pressure.
For example, if the oil pressure drops below the specified level or the discharge pressure exceeds the permissible limit, the differential pressure switch will trigger an alarm or shut down the system to prevent damage or accidents.