1. Power Supply Issues
The power supply is fundamental to the operation of the air compressor. Common problems include:

Incorrect wiring or unclosed power switches

Blown power fuses (must be replaced immediately)

Voltage lower than 90% of the rated voltage, which is insufficient to start the compressor

Power phase loss (common fault in three-phase motors)

Damaged power cables or loose plugs causing poor connections

2. Faults in the Starting Components and Control System

Faulty start button contacts or mechanical lockup

Start relay failure, causing a circuit break

Control panel issues, PLC program errors, or frequency converter malfunctions (e.g., overcurrent alarm E13)

Overload relay failure and failure to reset after disconnection

False temperature sensor alarms leading to protective shutdowns

3. Mechanical Failures in the Main Unit

Damaged internal bearings or worn gears

Loose internal parts causing abnormal noise and local overheating

Broken or severely worn drive belts

Motor faults: short-circuited windings, bearing wear, or insulation failure

4. Incorrect Operation and Environmental Factors

Improper button operation (e.g., pressing too hard, causing inability to reset)

Unopened outlet valve or excessively high pressure settings

Environmental factors: high/low temperatures or excessive humidity affecting performance

Excess moisture in the air causing electrical component short circuits

5. Abnormalities in Auxiliary Systems

Severe blockage of the air filter, preventing normal intake

Lubrication system failures: low oil levels, clogged oil passages, or degraded oil quality

Overloaded fan motor leading to poor heat dissipation

Hidden Culprits

1. Pressurized Start Problem
When the compressor shuts down, if the system has not fully vented, back pressure during startup can be too high. The simple check involves observing the mechanical pressure gauge on the oil-gas tank.

Try manually venting the system. If the pressure gauge still shows pressure, the gauge is faulty.

If there is no venting device, check if the minimum pressure valve or venting system is clogged.

2. Excessive Resistance in the Main Unit

Increased viscosity of winter lubricants: When the temperature drops below zero, water in the oil can freeze and block oil passages.

Fouling in the main unit: In screw compressors, fouling between the screw and star wheel can reduce gaps, increasing friction resistance.

Excess lubrication: Faulty oil shut-off valve causes excessive lubrication oil to enter the main unit after shutdown.

Solution: Before startup, manually rotate the unit to detect rotational resistance. In winter, use a jog mode to preheat the lubrication system.

3. Hidden Electrical Faults

Star-delta switch failure: This prevents proper conversion between star and delta operation, causing excessive startup current. Vibration of the air switch may shorten the set startup time.

Solutions and Preventive Measures

1. Power Supply Check

Measure input voltage, check fuses, and phase protection devices to ensure voltage is stable and within rated range.

2. Operational Check

Confirm that all buttons are properly reset, outlet switches are open, and parameter settings are correct.

3. Control System Check

Inspect alarm information on the control panel, reset protective devices, and test the start relay.

4. Mechanical System Check

Perform manual rotation to check for any abnormal resistance; inspect belt status and ensure no mechanical jamming.

5. Auxiliary System Check

Inspect the air filter for blockages, ensure proper oil levels, and drain the condensation from the oil-gas tank.

Preventive Maintenance

Electrical System: Tighten contactor wiring monthly, and periodically inspect motor insulation to prevent wiring loosening, which can cause up to 30% of failures.

Lubrication System: Regularly replace lubricants and filters as per the manual. Choose appropriate viscosity oils based on the season.

Control System: Clean temperature sensors and remove oil and dust quarterly. Calibrate pressure sensors.

Mechanical System: Perform regular manual rotation to check for resistance changes and replace worn belts in a timely manner.

Cooling System: Clean the cooler and remove accumulated dust every quarter to ensure proper heat dissipation and prevent overheating that could lead to a protective shutdown.

Safety Operating Standards

Always cut off power and hang warning signs before maintenance.

Close the gas system shutoff valve and open the manual drain valve to release system pressure.

For water-cooled units, shut off the water supply system and release the pressure from the water pipes.

Never disassemble nuts and components while under pressure.