Motor control
SIMOCODE pro
4-34 GWA 4NEB 631 6050-22 DS 03
Safety guidelines
Note
It is recommended to wire the QE1 and QE2 contactor controls to the relay
outputs of the basic unit. You need at least 1 digital module for this control
function.
Notice
If you use internal earth-fault detection for star-delta circuits, this can lead to
false trippings. During delta operation, the summation current is non-zero
due to harmonics.
Notice
If the current measuring module is switched to delta (normal case), a
current which is 1/ smaller than normal must be set for the star-delta
starter control function.
Example: I
n
= 100 A I
s
= I
n
x 1/
I
s
= 100 A x 1/ = 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 mains voltage plus motor EMF might lead to a very high delta
starting current if the change-over pause is too short. The motor EMF
decreases if the pause is longer.
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