Siemens SIMOCODE pro - Page 83

Parameters
4.2 Motor control
SIMOCODE pro - Parameterize
Operating Manual, 04/2017, A5E40507630002A/RS-AA/001
83
Safety guidelines
Note
It is recommended that contactor controls QE* are wired to the relay outputs of the basic
unit.
Note
if the
SIMOCODE pro S basic unit is used, an additional multifunction module is required for
this control function.
The typical change
-over time from star to delta is between 100 ms and 150 ms.
Note
Spurious tripping can occur if you use the internal ground
-fault detection for star-delta
connections. During delta operation, the su
mmation current is non-zero due to harmonics.
Note
If the current measuring module is switched to delta (normal case), a current which is 1/√3
times smaller must be set for the star
-delta starter control function.
Example: I
n
= 100 A
I
s
= I
n
x 1/√3
I
s
= 100 A x 1/√3 = 57.7 A
Current to be set I
s
= 57.7 A
Change-over pause
The switching time from star to delta can be extended by the change-over pause. Reason:
For motors with a high ratio between starting current and rated current, the line voltage plus
motor EMF might result in a very high delta starting current if the change-over pause is too
short. The motor EMF decreases if the pause is longer.