Allen-Bradley

AC servo AL009 — motor will not run after a coupling change

Hannah Cho · Night shift

Packaging line, third-party AC servo, alarm AL009 after maintenance swapped a jaw coupling. Drive enables, no motion. Encoder counts in the test mode. What does AL009 mean on your brand, and what did you check first besides the obvious wiring?

Brett Lang · Motion
AL009 on the units we see is encoder / speed-feedback abnormal. Coupling change is a classic: setscrew on the encoder hub slipped one flat. Jog in test, mark the shaft, command one rev, see if the display agrees. If counts look right but the machine doesn't move, the load side of the coupling is the one that is loose. Don't raise the following-error limit to hide it.

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