The blown fuse is a symptom of the true problem.
A fault of some type has caused the fuse to blow, and this could be for several reasons as:

• Quick repetitive switching to mains by applying input power more quickly causes the inrush limiters to overheat in the input precharge circuit and eventually burns them out. The dc bus capacitors don’t have enough time to discharge. If the input circuit doesn’t have time to stabilize, additional input current can blow the input fuses or circuit breaker and damage the charge circuit.
• Poor Earthing system and not following the EMC installation guidelines.
• Capacitor bank may result in undesirable resonant currents.
• Transient perturbation associated with the supply switching.

Released for:Schneider Electric Nigeria