904

LOW LINE VOLTAGE FAULT

Otis · DSD 412 Elevator System

What does 904 mean?

The AC input power has dropped below 80% of the Nominal AC Line Voltage #9 for 3 consecutive cycles or lower than 50% for one cycle. This sets the Severe Fault flag and forces the DSD 412 current reference to zero, shutting down the drive.

Common Causes

  • AC input power issues (voltage sag or prolonged low voltage).

Repair Steps & Checklist

Click steps to track your progress.

  1. 1

    Measure the AC input power voltage to ensure it stays above 80% of Nominal AC Line Voltage #9.

  2. 2

    Verify the stability of the AC input power supply.

Browse all codes in this manual (57)
Verified technical data. Last updated: March 2026

Related Faults

Source: Otis DSD 412 Elevator System