1
05.01
1.3 Engineering a drive
1-33
©
Siemens AG 2012 All Rights Reserved
SIMODRIVE 611 Configuration Manual (PJU) – 02/2012 Edition
1.3.1
Calculation of the required DC link power (P
ZK
) for dimensioning
the supply system, infeed unit
Steady–state operation:
P
ZK
= P
VSA ZK
+ P
MSD ZK
P
ZK
v
Pn
infeed module
S
Feed axes with rotary motors
The following formula is used in the engineering sheet to determine the cal-
culated power:
P
calc FD
= 0.105
⋅
M
0
⋅
n
n
⋅
10
–3
[kW]
Where:
P
calc FD
calculated power for feed axes [kW]
0.105
factor 2
⋅
π
/60
For feed axes, calculated with M
0
M
0
stall torque [Nm]
n
n
rated speed [RPM]
S
Feed axes with linear motors
P = F
n
⋅
V
MAX, FN
⋅
10
–3
[kW]
Where:
F
n
rated force [N]
V
MAX, Fn
maximum velocity at the rated force [m/min]
The DC link power P
VSA ZK
of the feed axes is calculated using the engineering
sheet. The following factors must be taken into account:
S
Speed ratio ñ/n
N
S
Coincidence factor K for the number of feed axes per area
If the exact values of the speed ratio ñ/n
N
and coincidence factor K are known
for the application in question, these should be used.
S
Main spindles
For main spindle drives, the efficiencies must be included in the calculation
and are roughly estimated using the following factors:
–
Motors
v
4 kW
P
MSD ZK
+
1.45
⋅
P
MSD motor shaft
[kW]
–
Motors
u
4 kW
P
MSD ZK
+
1.25
⋅
P
MSD motor shaft
[kW]
Where:
P
MSD ZK
DC link power for the main spindle drive [kW]
1.45 or 1.25
Assumed factor for the motor efficiency
P
motor shaft MSD
mechanical power [kW] used at the shaft of the
main spindle motor
The rated motor current may not exceed the rated output current of the
power modules. The maximum motor current must always be less than the
maximum converter current.
1 Overview of the Drive System
02.07
