EL
ErrorLib
Brands
||
  1. Home
  2. Fanuc
  3. AC Spindle Motor Alpha i-Beta i Series Parameters
  4. SP0004
About·Privacy·Terms

ErrorLib — Industrial Fault Code Library

Disclaimer: ErrorLib is an independent technical reference tool. While we aim for accuracy, always verify with the manufacturer’s official service manuals before performing maintenance on industrial equipment. ErrorLib is not affiliated with the brands listed.

SP0004

Converter Main Power Supply Open Phase

Fanuc · AC Spindle Motor Alpha i-Beta i Series Parameters

What does SP0004 mean?

An open phase condition is detected in the main power supply to the converter unit of the spindle amplifier. This indicates a loss of one or more phases in the AC input.

Common Causes

  • Failure of one or more phases in the incoming AC power supply.
  • Loose connections at the main power input terminals of the amplifier.
  • Faulty internal power factor correction (PFC) circuit.
  • Blown input fuse or circuit breaker for the converter.
  • Overheating of the converter power components.

Repair Steps & Checklist

Click steps to track your progress.

  1. 1

    Measure the AC input voltages (L1, L2, L3) at the amplifier's power terminals.

  2. 2

    Inspect all power input connections for signs of arcing or corrosion.

  3. 3

    Verify the main circuit breaker supplying power to the amplifier is not tripped.

  4. 4

    Check the status of any internal input fuses within the amplifier.

  5. 5

    Ensure the amplifier is operating within its specified ambient temperature range.

Browse all codes in this manual (60)
Verified technical data. Last updated: April 2026

Related Faults

749Serial Communication Error during Activation750Spindle Amplifier Not Activated (16i)PS0223Spindle Not Set for Control
Source: Fanuc AC Spindle Motor Alpha i-Beta i Series Parameters
Open Manual (Page 728)Search more codes in this manual