HMU05 systems for high leakage capacitances
DC bus choke, Y capacitor pairs
In drive systems with many axes, big motors and/or long motor power cables,
a DC bus choke (HLL05) can be used to increase the maximum allowed total
leakage capacitance of the drive system.
4 Y capacitor pairs (
) are assigned to each DC bus choke. The
Y capacitor pairs have to be distributed evenly in accordance with the leak‐
age capacitances connected to the inverters.
Damage to the Y capacitor pairs!
NOTICE
If the leakage current is distributed unevenly, Y capacitor pairs risk getting
overloaded and damaged!
Evenly distribute Y capacitor pairs in accordance with the leakage capacitan‐
ces connected to the inverters.
Example: 2 inverters at the DC bus with the same connected leakage capaci‐
tance. Consequently: 2 Y capacitor pairs are connected at the DC bus of
each inverter.
Mounting the Y capacitor pairs:
●
Mount them as near as possible to the DC bus bars of the inverters.
●
Mount the housing directly to the grounded back panel of the control
cabinet. Make sure the connection is highly conductive.
●
Use the shortest possible cables (cross section: 25 mm
2
) to connect Y
capacitor pairs to L+ and L- of the DC bus bar.
●
Always mount 4 Y capacitor pairs per DC bus choke.
Fig. 4-4:
HLL DC bus choke (left) and 4 Y capacitor pairs (right)
HMU05 systems with a single supply unit
For HMU05 systems with a single HMU05 supply unit, the maximum allowed
leakage capacitance increases to 1200 nF if the DC bus choke and the Y ca‐
pacitor pairs are used.
The number and operation mode (individual or parallel operation) of the
HMU05 inverters are irrelevant.
Bosch Rexroth AG
DOK-INDRV*-HXX05******-PR02-EN-P
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Rexroth IndraDrive ML Drive Systems with HMU05
Combining the individual components
