DC Bus Overvoltage

What does ov mean?

The DC bus voltage exceeded its trip point (e.g., ~410V for 200V class, ~820V for 400V class). This can result from surge voltage in the drive input power, a short-circuited motor, ground current over-charging the main circuit capacitors, or electrical signal interference affecting measurements.

Complete Troubleshooting Guide

1. 1

   Install a DC reactor or an AC reactor on the input side to suppress surge voltages in the drive input power.

2. 2

   Check the motor power cable, relay terminals, and motor terminal box for short circuits or grounding shorts and rectify any issues found.

3. 3

   Review and mitigate electrical signal interference by checking control circuit lines, main circuit lines, and ground wiring. Install a surge protector to the magnetic contactor (MC) coil if it's identified as a source of noise.

4. 4

   Set the number of fault restarts (L5-01) to a value other than 0 to prevent immediate reoccurrence after a fault trip, allowing time for investigation.