Nate Electrical Practice Exam

What occurs when the internal thermostatic overloads of an air conditioning compressor open?

1. High pressure control will open

2. Low pressure control will open

3. Oil failure control will trip off

4. Compressor will restart after cooling

The correct answer is: Oil failure control will trip off

When the internal thermostatic overloads of an air conditioning compressor open, it typically signifies that the compressor has overheated and needs to be protected from damage. This overheating can occur due to various reasons, such as insufficient refrigerant, excessive head pressure, or lack of lubrication. In this scenario, the thermostatic overload serves as a safety mechanism that trips the compressor off to prevent it from operating under unsafe conditions. By doing this, it helps ensure that the compressor has the opportunity to cool down, thus safeguarding the compressor from catastrophic failure. On the other hand, other responses involve control measures that are not directly linked to the function of internal thermostatic overloads. High or low pressure controls relate more to the refrigerant pressure conditions in the system rather than the thermal conditions of the compressor. The idea of the compressor restarting after cooling does not align with the immediate action taken by the overloads, as they are designed to protect the compressor from restarting while it is still in an overheated condition.