Siemens SIMOTICS-T 1FW68, Engineering Manual

Page: 92 / 180

Configuring
5.2 Mounting
1FW68 radial segment motors
92
Configuration Manual, 04/2017, 6SN1197-0AE02-0BP1
5.1.12 Calculation of the required infeed
Dimensioning the Active Line Module
Use the drive's power balance to dimension the Active Line Module.
The first important quantity to know is the mechanical power P
mech
to be produced on the
motor shaft. Based on this shaft output, the electrical active power P
Line
to be drawn from the
supply system can be determined by adding the power loss of the motor P
V Mot
, the power
loss of the Motor Module P
V MoMo
and the power loss of the Active Line Module P
V AI
to the
mechanical power P
mech
:
P
Line
= P
mech
+ P
V Mot
+ P
V MoMo
+ P
V AI
.
The active power to be drawn from the power system depends on the line voltage U
Line
, the
line current I
Line
and the line-side power factor cos φ
Line
as defined by the relation
P
Line
= √ 3 • U
Line
• I
Line
• cos φ
Line
.
This is used to calculate the required line current I
Line
of the Active Line Module as follows:
I
Line
= P
Line
/ ( √ 3 • U
Line
• cos φ
Line
).
If the Active Line Module is operated according to the factory setting, i.e. with a line-side
power factor of cos φ
Line
= 1, so that it draws only pure active power from the supply, then the
formula can be simplified to
I
Line
= P
Line
/ ( √ 3 • U
Line
).
The Active Line Module must now be selected such that the permissible line current of the
Active Line Module is higher or equal to the required value I
Line
.
5.2 Mounting
5.2.1 Safety instructions for mounting
WARNING
Risk of death and crushing as a result of permanent magnet fields
Severe injury and material damage can result if you do not carefully take into consideration
the safety instructions relating to permanent magnet fields of rotor segments.
•
Observe the information in Chapter Danger from strong magnetic fields (Page 31).