Introduction

Is your air compressor constantly tripping its circuit breaker, halting production lines and costing you valuable time? Frequent tripping isn’t just an annoyance—it’s a warning sign of underlying issues. In this guide, we’ll break down the air compressor motor overload causes and provide step-by-step diagnostics to get your equipment back online fast.

1.Unstable Power Supply Voltage

Voltage fluctuations are the number one cause of air compressor overload tripping. If incoming voltage drops below 90% or surges above 110% of the rated voltage (e.g., 198V–242V for a 220V system), the motor’s overload protector will trigger.

How to diagnose:

Use a multimeter to measure voltage at the compressor’s terminal during operation.
Check for loose wiring in the main circuit.
Pro Tip: Install a voltage stabilizer if fluctuations exceed ±10%.

’ Warm reminder: If you want to know more detailed troubleshooting methods and steps you can click here.

2.Motor Overload or Aging

This is the most common cause of air compressor overload tripping.
Worn-out motors draw excessive current, tripping thermal overload relays.
Common signs include:
Burning smell from windings
Abnormal noise from bearings
Current exceeding nameplate rating (test with a clamp meter)

Quick Fix:

Reset the overload relay after a 30-minute cooldown.
Replace motors showing insulation resistance below 1MΩ (megohm).

3.High Discharge Temperature

Overheating is also an important factor in the need to troubleshoot air compressor overload tripping.
Air compressors automatically shut down when discharge temps exceed 120°C (248°F) to prevent damage. Causes include:
Clogged oil cooler fins
Faulty cooling fan
Low lubricant levels

Diagnostic Steps:

1.Inspect the temperature sensor with an infrared thermometer.
2.Clean debris from cooling fins using compressed air.

’ Warm reminder: Want to learn about overheating factor testing? Click here.

4. Faulty Starter or Contactor

Oxidized contacts in magnetic starters increase resistance, forcing the motor to work harder. Symptoms:
Clicking sounds without motor engagement
Burnt marks on contact surfaces

Action:

Disconnect power and scrub contacts with fine-grit sandpaper.
Replace starters with pitted contacts deeper than 0.5mm.

5. Dirty Air Intake Filters 

Compressor tripping problem：

A blocked filter reduces airflow, causing the motor to overcompensate. This often triggers overloads in screw compressors.

Maintenance Rule:

Replace disposable filters every 3 months.
Wash reusable filters weekly in warm soapy water (if PM2.5 levels > 50).

Troubleshooting Flowchart

Follow this sequence to pinpoint issues:
Tripping on startup? Test power supply voltage.
Tripping mid-cycle? Check motor amps and cooling systems.
Random tripping? Inspect contactors and wiring.