Recently, a friend sent us a private message asking us that the screw air compressor in his factory suddenly loaded and tripped. Maintenance is still not possible. I want us to teach you how to deal with it. Today I will roughly talk about what is the problem of tripping when the air compressor is loaded, and how to deal with it.

1. Power supply and voltage problems

1. Causes of voltage abnormalities:

Unstable power supply voltage (too high or too low), missing phase of the three-phase power supply or wrong phase sequence cause the motor protection device to trigger tripping.

Treatment: Check if the grid voltage is within the rated range (such as 380V±10%), ensuring that the wiring is secure and the phase sequence is correct; If there is an undervoltage or overvoltage problem, it is necessary to contact the power department to adjust or install voltage stabilization equipment.

2. The exhaust pressure or load is too high

1. Reasons for exhaust pressure exceeding the rated value:

The exhaust pressure of the unit exceeds the set value, resulting in motor overload or thermal protection action. Treatment: Check whether the pressure gauge is normal, adjust the upper limit of the pressure switch to a reasonable range (usually lower than the opening pressure of the safety valve by 0.1-0.2MPa).

2. Start with pressure

Cause: The residual pressure of the system is not released after the shutdown (such as the minimum pressure valve failure or the pressure relief pipeline is blocked), resulting in excessive starting current.

Treatment: Check the pressure gauge of the oil and gas cylinder, if there is still pressure after stopping, clean the pressure relief system or replace the minimum pressure valve.

3. Mechanical and lubrication system failure

1. Causes of excessive nose resistance:

The coking of the machine head, the viscosity of the lubricating oil is too high, or the amount of oil is too high, resulting in abnormal starting current.

Treatment: Manual coil head check resistance, replace lubricating oil (choose oil with suitable viscosity level) or clean up coke if necessary; If the oil shut-off valve fails and the oil volume is too high, the oil shut-off valve needs to be repaired or replaced.
2. Causes of wear or foreign objects entering mechanical components: wear of bearings, gears, or carbon deposits in the rotor, increasing operating resistance. Treatment: Regularly overhaul the main engine and replace worn parts; Check the air filter for clogging to prevent foreign objects from entering the nose.

4. Protection device setting or failure 1. The reason for the low overcurrent protection value is that the set value of the protection device is lower than the actual load current, resulting in malfunction. Processing: Recalibrate the overcurrent protection value to ensure that it matches the motor nameplate parameters.

The reason for the low overcurrent protection value is that the set value of the protection device is lower than the actual load current, resulting in malfunction. Processing: Recalibrate the overcurrent protection value to ensure that it matches the motor nameplate parameters.

Causes of oil separator blockage: The oil partial pressure difference is too large (more than 0.08MPa), resulting in an increase in motor load. Treatment: Replace the oil separator and check whether the lubricating oil is contaminated or deteriorated.

5. Other common reasons

Fault handling of lines or contactors: Check for loose lines, oxidation or aging of contactor contacts, and replace them if necessary.

Exhaust temperature is too high: clean the cooler, check the amount of lubricating oil and whether the temperature control valve is correct
3. Poor lubrication

Treatment: Use lubricating oil that meets the specifications, and change the oil filter and oil regularly.

Comprehensive treatment suggestions

Regular maintenance: including replacing air filters, oil filters, oil cores and other wearing parts, cleaning coolers and pressure relief pipelines.

Parameter calibration: Check the set values of protection devices such as pressure switches and temperature sensors to avoid drift or malfunction.

On-load test: Extend the motor start-up time within a safe range to avoid excessive instantaneous current caused by excessive oil viscosity.

If the problem still cannot be solved, it is recommended to contact professional maintenance personnel or equipment manufacturers for further diagnosis to avoid expanding the fault due to misoperation.