DC Bus Overvoltage

Was bedeutet OV ?

The DC bus voltage exceeded its trip point (≥400Vdc for 208-240Vac Drives; ≥800Vdc for 480Vac Drives). This is often caused by high input voltage, overly short deceleration times leading to regenerative energy, or the presence of power factor correction capacitors on the input. Overvoltage can severely damage drive components.

• Input AC line voltage at R/L1, S/L2, T/L3 terminals is consistently higher than the drive's rated input voltage.
• Regenerative energy from the motor during rapid deceleration is returning to the DC bus without adequate dissipation.
• Deceleration time parameters (e.g., C1-02, C1-04) are set too short for the load's inertia, causing voltage spikes.
• Faulty or absent braking chopper/resistor circuit (if required) preventing regenerative energy dissipation.
• Poor input power quality with significant voltage swells or transient overvoltages.

Klicken Sie auf Schritte, um Ihren Fortschritt zu verfolgen.

1. 1

   1. Using a multimeter, measure the AC input voltage at R/L1, S/L2, T/L3 terminals and verify it is within the drive's specified range.

2. 2

   2. Measure the DC bus voltage across the P(+) and N(-) terminals on the drive during operation, especially deceleration events.

3. 3

   3. Increase the deceleration time (e.g., parameter C1-02 or C1-04) to allow for slower energy dissipation.

4. 4

   4. Verify the braking resistor (if installed) is properly sized, connected, and its chopper circuit is functional.

5. 5

   5. Check for external power factor correction capacitors upstream that might be overcorrecting and causing voltage rise.