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MSD Multi-Axis System Operation Manual DC-AC Servo Drive
However, it is then not possible to feed power back to the supply system. Regenerative
power produced must be dissipated via a braking resistor and converted into heat.
NOTE:
You will find details on dimensioning the braking esistor in
.
DC link power and total DC link capacitance of the AC-AC Servo Drive
For an initial estimation as to whether an AC-AC Servo Drive is adequate for supplying
other DC-AC Servo Drives, the power available from the AC-AC Servo Drive DC link can
be calculated approximately using the following formulae:
P
rated
= √3 . U
Mains
. I
rated (f
SW
and U
mains
)
. 0.8
P
Max
= √3 . U
Mains
. I
Max (f
SW
and U
mains
)
. 0.8
Here I
Rated (fsw and U_Mains)
is the rated current and I
MAX (fsw and U_Mains)
the maximum current from
the AC-AC Servo Drive corresponding to the switching frequency of the power stage
and the mains voltage.
CAUTION
!
Damage to the device due to exceeding the maximum power.
•
The device may suffer irreparable damage.
The power figures are a root-mean-square value over one load cycle. The maximum power is
not allowed to be exceeded at any time and is only allowed to be drawn for the stated time, as
otherwise the AC-AC Servo Drive will be irreparably damaged.
Example calculation: supply with Power Supply Unit
Two DC-AC Servo Drives G393-024/G397-026, two DC-AC Servo Drives G393-060/
G397-070 and one DC-AC Servo Drive G393-090 are to be connected to one Power
Supply Unit G396-075.
Calculation:
1 x 4240 µF + 2 x 504 µF + 2 x 900 µF + 1 x 1060 µF = 8108 µF
Result:
The Power Supply Unit is adequately dimensioned with a max. total
DC link capacitance of 9200 µF
.
NOTE:
Note that it is necessary to take into account not only the DC link capacitance
of the DC-AC Servo Drives, but also the capacitance of the Power Supply
Unit.
9.7.5
External components
On the usage of a Power Supply Unit you need additional components:
•
Mains connection set comprising mains filte , input choke incl. capacitor, step-
up choke, EMC fastening material)
On this topic see MSD Or
dering Catalog (ID no.: CDL 29950-en).
9.7.6
Selection of a suitable AC-AC Servo Drive as supply
With a low simultaneity factor in the axis group, it may be possible to select the largest
axis as an AC-AC Servo Drive that can take over the supply for the entire axis group. To
identify a suitable AC-AC Servo Drive, a power/time diagram over a complete load cycle
must be available for all axes. Figur
contains an example.
The power required by each individual axis (incl. the AC-AC Servo Drive axis) at each
point in time is added together to produce the overall power/time diagram. The following
characteristic data can be derived from this diagram:
•
Nominal power consumption of the AC-AC Servo Drive axis
•
Maximum power consumption of the AC-AC Servo Drive axis
•
Nominal regenerative power
•
Maximum regenerative power
moog
Id. no.: CA97554-001 0
5
/2017
9 Planning
