Applicable Systems
GA Series Compressed Air System
Symptoms
The Atlas Copco controller displays E09, indicating the input power voltage is abnormal. The supply voltage has fluctuated outside the acceptable range.
Possible Causes
- Power grid voltage unstable with large fluctuations
- Transformer tap setting incorrect for the actual line voltage
- Power cable too long causing voltage drop under starting load
- Voltage monitoring relay or sensor defective giving false readings
Troubleshooting Steps
- Step 1: Measure input voltage at compressor terminals during startup and running
Voltage should remain within +/-10% of rated voltage under all load conditions - Step 2: Check transformer tap settings if applicable
Tap setting should match the actual line voltage to ensure proper output - Step 3: Verify power cable size and length against specifications
Cable must be sized to prevent excessive voltage drop during motor starting - Step 4: Compare controller voltage reading with external multimeter
If readings differ significantly, the voltage sensor may need calibration or replacement
How to Reset
To reset: 1) Correct the voltage condition. 2) Power cycle the compressor controller. 3) Monitor voltage during operation. Caution: Operating with abnormal voltage can damage the motor windings and control electronics.
Frequently Asked Questions
- Q: What voltage range is considered normal for Atlas Copco compressors?
The acceptable range is typically +/-10% of the rated voltage. For a 400V system, that is 360V-440V. Check the specific model manual for exact tolerances.
- Q: Will E09 clear automatically when voltage stabilizes?
Some Atlas Copco controllers will auto-reset when voltage returns to normal range. However, repeated voltage instability indicates a power supply problem that must be addressed.
Source: Atlas Copco GA Series Compressor Fault Code Analysis, Atlas Copco Service Documentation
Category: Air Dryer