ABB ACS800 Common Fault Codes – Part 2

ABB’s ACS800 Variable Frequency Drive is powerful AC drive that can handle applications from 0.75 to 7500 horsepower with ease. Advanced harmonics mitigation technology provide a cost efficient solution to meet your most stringent power quality standards.

The ACS800’s highly flexible, highly programmable platform makes integrating the drive into just about every drive-motor application you can think of. The drive’s “Everything Inside” design makes it fantastic “plug-and-play” tool but the drive really shines when it is tailor made for your most precise applications. The drive is suitable for use in process industries such as pulp and paper, metals, mining, cement, power, chemical, and oil and gas. The ACS800 can even be found powering offshore supply vessels in the Gulf of Mexico!

Because the ACS800 is such a valuable tool, it can be a headache when something goes wrong. With dozens of fault codes to parse and diagnose, it may be difficult to identify where your drive is encountering issues. To help you diagnose issues you’re having with the ACS800, we’ve composed this guide to give you a head start when troubleshooting your drive.

This is Part 2 in a five-part series. (Part 1)




Motor Phase #FF56

When the drive detects a motor phase fault, its display will show “MOTOR PHASE (FF56)” on the control panel, 3rd line down.

This fault is indicating that one of the motor phases is lost due to a failure in the motor, the motor cables, thermal relay (if used) or an internal drive fault.


  • Check motor and cable.
  • Check thermal relay (if used)
  • Check fault function parameter 30.16 (this parameter can be disabled)
  • Check the drive’s internal BUS connections and make sure the terminal lugs are tight

This drive fault can be disabled at parameter 30.16 by entering a 0. Enter 65535 to activate.


Underload #FF6A

If the motor load is too low, the ACS800 will detect an underload fault and display “UNDERLOAD (FF6A)” on the control panel, 3rd line down.

This fault is indicating the motor load is low due to some type of release mechanism in driven equipment for a constant torque application, or an airflow restriction like a closed vain in case of an HVAC blower.


  • Check for a problem in the driven load
  • Check fault function parameters (30.13 to 30.15)

Parameter 30.13 decides what type of action to take (none, warning or fault). 30.14 sets the time delay to action. 30.15 sets the torque curve (5 different options are shown).


Stay tuned for Part 3! If you have any questions about the ACS800 or drive fault codes, contact our experts today!


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