44 Rockwell Automation Publication MOTION-AT007A-EN-P - May 2020
Chapter 4 Regenerative Bus Supply Configurations
System Sizing
These limitations apply to systems supplied by 2198-RPxxx regenerative bus supplies:
• The sum of the inverter motor-power cable lengths for all inverters on the same DC bus-sharing group must not exceed 1200 m
(3937 ft) to comply with IEC 61800-3 (category C3) requirements when used with 2198-DBRxx-F line filters. 2198-DBxx-F line filters have
a total motor cable length limit of 400 m (1312 ft). See the Kinetix 5700 Servo Drives User Manual, publication 2198-UM002
, for
additional motor power cable-length limitations.
• The total system capacitance limit is based on the power supply catalog number. DC-bus groups must not exceed the limits as
defined in Kinetix and PowerFlex Drive Specifications
on page 59.
• If using the 24V DC shared-bus connection system, add another 24V power supply when control input power to a cluster of drive
modules exceeds 40 A.
• The Kinetix 5700 system can have multiple drive clusters in a single DC-bus group. See the Kinetix 5700 Servo Drives User Manual,
publication 2198-UM002
, for more information on extended clusters.
Refer to the Kinetix 5700 Servo Drives User Manual, publication 2198-UM002
, for additional information on system sizing guidelines.
The motor required for a particular application determines the drive required for full motor performance. For best results, use the Motion
Analyzer system sizing and selection tool, available at https://motionanalyzer.rockwellautomation.com/
.
Capacitance Sizing
Total system capacitance is the sum of all internal capacitance values from each of the drive modules (AC drives, single-axis inverters, dual-
axis inverters, power supplies, and capacitor modules) in the same DC-bus group.
The total system capacitance must be less than the maximum supported DC-bus capacitance value of the power supply (refer to Kinetix and
PowerFlex Drive Specifications on page 59).
External bus capacitance is the total system capacitance minus the power supply capacitance. The external bus capacitance must be
entered into the Logix Designer application for a regenerative power supply to maintain proper control.
All drives have a DC-bus capacitance that is proportional to their power ratings. When used in a common DC-bus configuration, these
capacitors are directly connected in parallel. This connection results in the DC-bus ripple being shared proportional to the power rating of
the drive. When the ratio of the capacitance to the drive-rated current is consistent, it provides the best DC-bus ripple sharing.
For 400/480V AC, the target ratio is 40 µF/A ±10% or greater. For all drives supported in this publication, the target ratio is met when a
capacitor module is used to extend the DC-bus, proper DC-bus cable length guidelines are followed, and low-inductance DC cable is used.
See DC-bus Connections
on page 8 for more information.
Circuit Protection
Do not daisy chain drives to share DC-bus fusing. Configure the shared DC-bus in a star configuration to enable proper fusing. Use fast
semiconductor fuses in the DC links to minimize destructive energy in the event of a part or control malfunction. Size fuses to handle large
peak currents at the end of precharge.
•See Kinetix and PowerFlex Drive Specifications
on page 59 for the recommended common DC-bus circuit protection devices.
• See the Kinetix 5700 Servo Drives User Manual, publication 2198-UM002
, for recommended AC input circuit protection for the Bulletin
2198 power supply.
IMPORTANT If your total system capacitance value exceeds the maximum supported capacitance value of the regenerative bus supply,
perform one of the following:
• Increase the size of the 2198-RPxxx regenerative bus supply
• Decrease the total system capacitance by removing inverters or capacitor modules from the DC-bus group
• Separate clusters into multiple DC-bus groups
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