08420000 hex

Motor Overheat Error

Omron · NJ/NX-series Machine Automation Controller

What does 08420000 hex mean?

The encoder detected the temperature that exceeded the protection level of motor. This suggests the motor is operating under conditions that lead to excessive heat, risking damage to the motor windings and encoder.

Common Causes

  • The temperature is high around the motor
  • The motor is overloaded
  • Encoder failure

Repair Steps & Checklist

Click steps to track your progress.

  1. 1

    Inspect motor cooling fins, ventilation paths, and mechanical load for any obstructions, excessive friction, or binding.

  2. 2

    Verify drive parameters such as motor rated current, overload protection, and acceleration/deceleration times against motor specifications and application requirements.

  3. 3

    Monitor the actual motor operating current during representative load conditions and compare it to the motor's rated current and drive current limits.

  4. 4

    Check the encoder cable and motor temperature sensor wiring for continuity, proper connection, damage, and shielding integrity at both the motor and drive ends.

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Verified technical data. Last updated: March 2026

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Source: Omron NJ/NX-series Machine Automation Controller