Rockwell Automation 2364P Parallel DC Bus Supply Config. - Manual (Page 14)

Publication 2364P-5.01 December 1999
1-2 Theory of Operation
Parallel configurations use the following front-end units:
• Regenerative DC Bus Supply Unit (RGU)
• Non-Regenerative DC Bus Supply Unit (NRU)
Each parallel configuration will include one, two, or three
Regenerative DC Bus Supply Units (RGUs). These units are used to
supply motoring current to the DC bus, and are used to regenerate
current back onto the AC line.
Most of the parallel configurations will also include a
Non-Regenerative DC Bus Supply Unit (NRU) to supply the
motoring current to the DC bus.
Note: When there is an NRU in the configuration, the NRU
supplies motoring current while the RGUs regenerate most of the
excess capacity (the RGU also contributes 10% of its rated
motoring current to the DC bus).
Figure 1.2
NRU and RGU Operation
R GU
M otoring
C urrent
R egen erating
Cu rrent
N R U R GU
3-Phase
A C Line
D C S up ply for
D rive Lineup
10%
M otoring
C urren t
Reg enerating
C urren t
M otoring
C urrent
R GU
3-Phase
A C Line
D C S up ply for
D rive Lineup
M otoring
C urren t
Reg enerating
C urren t
N RU//R GU Con fig uration
RGU //RG U C onfigu ration