Rockwell Automation 2364F Regenerative DC Bus Supply Unit (RGU) - Manual (Page 215)

Publication 2364F-5.01– October 2003
Glossary G-3
Motor Control Center (MCC)
An enclosure which is used for the RGU. The MCC for the RGU includes a horizontal
DC bus.
Motoring Current
Current which is being supplied to the inverters (through the DC bus) for motoring.
Non-Regenerative DC Bus Supply Unit (NRU)
A six-pulse DC power supply produced by Rockwell Automation The NRU is typically
used as a front end power supply on a drive system lineup.
Overload
A condition where the unit is supplying current above its rated current. For example,
operating a unit at 150% overload would indicate that the unit is supplying 150% of its
rated current. Most units can operate with an overload condition for a short period of time.
PE (Potential Earth Ground)
A safety ground which is used to ground hardware in the system.
Power Factor (pf)
A measurement of the time phase difference between the voltage and current in an
AC circuit.
Power Module
A transistor used in the RGU and 1336 products to convert regulated power between
AC and DC. See also insulated gate bipolar transistor (IGBT).
Power Structure
A 3-phase power bridge built in the RGU which converts AC to DC (motoring current)
and DC to PWM AC (regenerative current). The power structure includes control boards,
a precharge circuit, a power bridge, and a capacitor bank.
PWM (Pulse-Width Modulation)
A method which is used to control and maintain a nominal output voltage. Transistors
(IGBTs) ‘chop’ the input into pulses, which allow an appropriate amount of current to
flow to the output. With appropriate control, the current pulses will produce a steady
output voltage.
Regenerative DC Bus Supply Unit (RGU)
A regenerative DC power supply unit produced by Rockwell Automation. The RGU is
typically used as a front end power supply to provide motoring and regenerative current
for a drive system lineup.