1160

Common Causes

• Unstable or incorrect shop supply voltage to the machine
• Faulty power unit
• Loose or damaged power cables or connectors between the supply and the power unit
• Instantaneous power interruption or dip from the plant supply

Troubleshooting Steps

1. 1Read the code number shown with the alarm: code (value) = Detected abnormal voltage expressed in hexadecimal volts
2. 2Read the code, which is the detected abnormal voltage in hexadecimal volts, and compare it against the machine's rated supply to see whether the excursion was high or low.
3. 3Check whether the alarm coincided with other plant events (large machines starting, visible light flicker, storms) that point to an instantaneous power interruption or dip on the shop supply.
4. 4Measure the incoming three-phase supply at the machine's main disconnect with a meter; look for low, high, or unbalanced phases and loose terminations. Lock out power before opening any panel and treat all terminals as live until verified.
5. 5With power locked out, inspect the power cables and connectors from the disconnect/transformer to the power unit for loose lugs, heat discoloration, or damaged insulation, and retighten as needed.
6. 6If the incoming supply is stable and the wiring is sound but the alarm persists, the power unit itself is suspect; record the alarm number, code value, and axis/spindle object and contact Okuma service.