Fanuc alarm SV0454: ILLEGAL ROTOR POS DETECT

What it means

Initial magnetic pole position detection ended abnormally because the motor did not move during the estimation routine. Without knowing rotor angle, the driver cannot energize phases correctly, so initialization aborts. Check for mechanical lock, brake still engaged, or excessive static friction preventing the small test movement the algorithm requires.

Likely causes

• Brake not releasing (vertical axis)
• Axis mechanically clamped or crashed into stop
• Extreme static friction/lack of lubrication
• Motor or power wiring fault preventing torque generation