Industrial Engineer · phase 14 of 16
DC Bus Overvoltage
Trip caused when DC-link voltage rises above its safe limit, often during rapid deceleration or high line voltage.
The Explain card
- Plain English
- A bus overvoltage trip fires when the DC link rises past its safe limit. The usual cause is the motor regenerating faster than the drive can absorb, and the other one is a high incoming line.
- Example
- A fan is set to decelerate in five seconds. The bus climbs past 800 volts on the way down and the drive trips, leaving the fan to coast.
- Why it matters
- It is the most common fault on drives with fast ramps and heavy loads. The cures are a longer deceleration, stall prevention, a braking resistor, or a regenerative front end, and the fault history tells you whether it happens on stops or at random.
- Hook
- The energy came back and had nowhere to go.
Where it sits in the deck
Phase 14: VFD Safety, Faults, and Diagnostics
What a drive does when it trips, what the fault codes are telling you, and how safe torque off stops the motor without killing the panel.
