SP9010 (Alarm 10) Spindle Low Input Voltage fault in Fanuc drive

SP9010 (Alarm 10) Spindle Low Input Voltage fault in Fanuc drive

Description

SP9010 (Alarm 10) indicates a voltage sag specifically affecting the Spindle Amplifier's power section. While the PSM regulates the DC bus, the Spindle drive often has its own AC monitoring or DC bus monitoring threshold that is tighter than the servo drives. This alarm triggers if the DC voltage drops below a level where the spindle can maintain torque control, often during heavy acceleration.

Cause

• Brownout: The shop voltage dips momentarily when a large compressor or other machine starts up.
• Undersized Transformer: The isolation transformer feeding the machine is too small for the peak load.
• Loose Connection: A high-resistance connection on the input power lines causes voltage to drop under load.

Solution

1. Monitor Voltage: Measure the incoming line voltage during a spindle ramp-up. If it drops more than 10%, your supply is too weak.
2. Check Taps: If you are in a region with 200V/208V/230V variance, ensure the machine transformer taps are set correctly to output 200-220V.
3. Tighten Terminals: Check the input terminal block on the spindle drive.