Vacon · NXS NXP
The DC-link voltage within the drive has exceeded its predefined safe operating limits. Common causes include overly short deceleration times, high overvoltage spikes from the incoming AC supply, or a very rapid Start/Stop sequence. Sustained overvoltage can lead to critical damage to the drive's DC-link capacitors and IGBTs.
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Measure the incoming AC supply voltage at the drive input terminals (L1, L2, L3) using a true RMS multimeter to confirm it is within the drive's rated input voltage range.
Increase drive parameter P2-02 (Deceleration Time) by 25% and observe DC-link voltage during deceleration using the drive's diagnostic display (e.g., A5-02).
If a braking resistor is installed, verify its resistance with a multimeter against the specified value, and check wiring to the drive's R+/RB terminals.
Enable or adjust the 'DC-link Overvoltage Controller' parameter (e.g., P6-10) to optimize deceleration ramp behaviour.
Check for sudden mechanical load reversals or rapid changes in process speed that could induce regenerative energy.