When The Inverter Trips The 0V During Inverter Deceleration - Hitachi BRD-E2-30K Operation Manual

5.2 When the inverter is tripped by overvoltage during inverter deceleration
This event may be caused by too much regeneration energy, which is unable to
handle the increase in voltage.
To prevent this problem, check and correct the resistances of the discharging
resistors, the number of dynamic braking units in use, and the deceleration time.
This problem occurs also when the discharging resistor is disconnected, when
wrong connections are made or when the DIP switch setting is improper. Follow
the instructions below to inspect and repair.