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8-6
Determination of Appropriate Power Supply Units
Mains voltage
storable energy per mF auxiliary capacitance
8.5
Continuous Regenerated Power
The auxiliary capacitor must be designed so that it is capable of storing
rotary drive energy:
≥
C
Zu
2
U
B
U
:
bleeder actuation threshold (approx. 820 V)
B
U
:
DC bus nominal voltage
ZW
W
:
rotatory energy [Ws]
rot
C
:
auxiliary capacitor [mF]
Zu
C
: internal capacitance of supply unit [mF]
HMV01.1Ein intern
Fig. 8-17:
Required auxiliary capacitance
In power supply units with regulated DC bus voltage (HMV01.1R)
approximately 75 Ws per mF auxiliary capacitance can be stored.
In power supply units with unregulated DC bus voltage (HMV01.1E) the
auxiliary capacitance should be designed for 10% overvoltage. The
storable energy per mF auxiliary capacitance is listed in the table below.
3 x AC 380 V
163 Ws
Fig. 8-18:
Storable energy with auxiliary capacitance on an HMV01.1E
The average sum of the continuous regenerated power of all drives may
not exceed the continuous regenerated power in the HMV01.1R or the
continuous bleeder power in the HMV01.1E.
Note:
For operation with continuous power, an additional load
caused by DC bus short circuit is no longer allowed.
The processing time in servo drive applications given a typical NC
machine tool, is relatively long in terms of the entire cycle time. There is
little regenerated continuous power. An exact calculation is generally not
required. It suffices if the peak regenerated power is not exceeded.
An exact calculation is needed in specific cases such as, for example:
• servo drive applications with numerous accel / decel procedures such
as is the case in nibble machines and rollers
• machine tools with modular main drives
• applications in which excessive masses must be lowered as is the
case with those overhead gantries used with storage and transport
technologies
To calculate continuous regenerated power, the rotary energy of the
drives and the potential energy of non-compensated masses must be
known.
W
:
rotary energy [Ws]
rot
n
:
speed in rapid traverse [min
eil
J
:
moment of inertia (motor + load) [kgm²]
g
z:
number of decels per cycle
Fig. 8-19:
Rotary energy
2W
rot
−
*
1000
C
HMV01.1Ein
2
−
U
ZW
3 x AC 400 V
3 x AC 440 V
144 Ws
103 Ws
2
π
J
2
g
=
W
*
n
*
*
rot
eil
2
60
-1
]
DOK-INDRV*-HMV-*******-PR01-EN-P
Rexroth IndraDrive
tern
3 x AC 480 V
89 Ws
z
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