There are several reasons why an air compressor may be overloaded and the service is down:

1.Excessive load: If the working pressure of the air compressor is too high, or the pipeline is blocked, it may cause the motor to be overloaded. It is necessary to inspect and clean the pipeline in time, adjust the working pressure, and ensure that the load is within a reasonable range.

2.Excessive overload time: The air compressor is in a state of overload for a long time, and the motor will stop working because of overload. The working time and load should be reasonably arranged, and the cooling time of the air compressor should be appropriately increased to reduce the workload.

3.Improper maintenance: The air compressor is not maintained according to the correct maintenance plan, which may lead to overloading of the motor.

4.Unstable voltage: Unstable power supply voltage can also lead to motor overload. The power supply needs to be checked and made sure of its stability.

5.Motor failure: Damage or aging of the motor can also lead to motor overload, such as broken windings or damaged bearings.

6.Three-filter blockage: The air inlet filter, oil filter and oil-air separator of the air compressor are blocked, which may lead to insufficient air intake or poor oil circuit, resulting in overload.

7.Pressure controller failure: Pressure controller failure may cause the air compressor to continue to load but not unload, resulting in overload.

8.Lubricating oil problem: The oil separator is blocked or the lubricating oil level is too low, resulting in insufficient lubrication of the main engine and causing overload.

9.Mechanical failures: mechanical problems such as damage to the main engine or motor bearings, sagging belts, etc., can also lead to overload.

10.Ambient temperature is too high: The working environment temperature of the air compressor is too high, and the cooling effect is not good, which may also lead to overload of the motor.

11.Control system failure: The control system of the air compressor is faulty, such as the contactor, relay and other components are damaged, which may also lead to the motor overload.

Solving these problems usually requires inspection and repair by a professional technician. Regular maintenance and inspections can help prevent overload situations from occurring.