Unidrive Regen Installation Guide
35
Issue Number: 2
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A.7
Regen brake drives in operation
A.7.1
Sequence
If the Regen brake drive and motoring drive are supplied from a separately switched AC supply then the Regen brake drive supply should be
energised first (or both at the same time). Similarly the Regen brake drive should also be powered down first (or both at the same time).
The motoring drive must only be enabled when the Regen drive is enabled, healthy, and synchronised to the AC supply. This will prevent any damage
to the Regen start-up circuit and prevent OU trips.
A.7.2
Regen parameter settings
It is very important that the Regen drive DC bus voltage set point is set above the peak AC supply voltage. If this is not done then power will flow from
the AC supply into the motoring drive, through the DC bus diode and back through the Regen drive to the AC supply. This will continue until the
Regen drive trips or part of the circuit is damaged. If possible the DC bus voltage set point should be at least 50V above the peak AC supply voltage.
With a larger difference between the peak AC supply voltage and the DC bus voltage set point there is more energy storage available for transient
peaks in the braking power. Table A-3 gives recommended DC bus voltage set points.
Table A-3
DC bus voltage set points - Pr 15.07 (Pr 0.17)
Supply Voltage
Recommended
Maximum
Vac
Vdc
Vdc
380
700
800
415
700
800
480
780
800
