WERCSWERCSDiagnose

ABB ACS580 VFD

ABB ACS580 VFD code A784: Motor disconnect

All three output phases are disconnected from the motor, which prevents the drive from running it.

Code
A784
Name
Motor disconnect
Controller
ABB ACS580 VFD
Type
General fault
What it does
Warning: the equipment keeps running and flags a problem
Risk
GREEN In your wheelhouse
Reset
Clears on its own when the condition goes away
Source
The manufacturer's manual (subscribers see which manual and page)

Updated November 4, 2026

How to fix it

Subscribers get:

  • What to do next, in plain words
  • What the manual says to do, and the page it is on
  • Booking a live video call with Ben, a master booth technician ($250/hr, paid per call)

Questions about this code

What does ABB ACS580 VFD code A784 mean?

All three output phases are disconnected from the motor, which prevents the drive from running it.

Is ABB ACS580 VFD code A784 dangerous?

It is graded green: in a working tech's wheelhouse with standard tools and low risk.

How do I fix ABB ACS580 VFD code A784?

The manual's fix and the step by step check for this code are in WERCS Diagnose, plans from $49 a month. For help right now, WERCS answers 24/7 at (877) 489-3727.

Other ABB ACS580 VFD codes

All 191 ABB ACS580 VFD codes · Every fault code