SP9015 (Alarm 15) Spindle Switching / Output Switch fault in Fanuc drive

SP9015 (Alarm 15) Spindle Switching / Output Switch fault in Fanuc drive

Description

SP9015 (Alarm 15) relates to Spindle Motors that have dual winding configurations (High Speed / Low Speed windings) or machines that use a wye-delta switch for torque control. The drive uses a magnetic contactor to physically switch the motor connections between Winding A and Winding B. SP9015 triggers if the switching sequence fails to complete, or if the drive detects that the output contactor is stuck in the wrong position.

Cause

• Stuck Contactor: The magnetic contactor responsible for switching windings is welded shut or the coil is burnt.
• Auxiliary Contact: The drive monitors the "Answer back" signal from the contactor's auxiliary pins. If the contactor moves but the aux switch is dirty, the drive thinks it failed.
• Relay Failure: The relay on the drive board that sends the 24V signal to the contactor coil is bad.

Solution

1. Check Contactor: Locate the winding switch contactors (usually near the drive). Manually depress them (with power off) to ensure they move freely.
2. Check Coil Voltage: Command a gear shift (e.g., M41/M42). Measure if 24V or 110V is reaching the contactor coil.
3. Check Signals: Verify the feedback signal wiring from the contactor back to the Spindle Drive interface connector.