Bosch Rexroth IndraDrive HMV01.1E-W0030, Project Planning Manual, Page: 76 / 132

8-4
Determination of Appropriate Power Supply Units Rexroth IndraDrive
DOK-INDRV*-HMV-*******-PR01-EN-P
If main and servo drives are operated on a power supply unit, the required
DC bus continuous power needs to be added.
It is the spindle drive in a NC machine tool that primarily determines the
DC bus power needed. Therefore, the following equation should be
applied in such applications:
25 , 1 * )] P ... P P ( * 3 , 0 P [ P
mSen 2 mSe 1 mSe mHa ZW
+ + + =
0,3: experimental value for standard machine tools
1,25: constant for motor and controller efficiency
P
ZW
: DC bus continuous power [kW]
P
mSe1
... P
mSen
: continuous mech. servo drive output [kW]
P
ZWHa
: nominal power for spindle drives (shaft output) [kW]
Fig. 8-11: DC bus continuous power for spindle and servo drives in machine
tools
8.3 DC Bus Peak Power
The DC bus peak power is demanded of the power supply unit when, e.g.,
several axes of a machine tool simultaneously accelerate to rapid
traverse and then go to a workpiece after a tool change.
CAUTION
Damages due to overloaded power supply unit!
⇒
Damages to the power supply unit can be avoided, if
the sum of the peak power of all drives does not
exceed the DC bus peak power of the power supply
unit.
9550
25 , 1 * n * ) M M (
P
eil G NC
ZWS
±
=
1,25: constant for motor and controller efficiency
M
NC
: acceleration torque in NC mode [Nm]
M
G
: weight torque in vertical axes [Nm]
n
eil
: speed in rapid traverse [min
-1
]
P
ZWS
: DC bus peak power [kW]
Fig. 8-12: DC bus peak power per drive
∑
≤
03 ZWS ZWS
P P
P
ZWS
: DC bus peak power [kW]
P
ZWS03
: DC bus peak power of the power supply unit [kW]
Fig. 8-13: Sum of DC bus peak powers
DC bus continuous power for
main and servo drives