Functions
6.7 Substation monitoring
Motor starter (3RK1308‑0**00‑0CP0)
94
Equipment Manual, 11/2019, A5E34821005002A/RS-AC/003
6.7.3
Upper/lower current limit
You can enter an upper and/or a lower current limit. The current limits are deactivated by
default. If the current limits are overshot or undershot, the motor starter responds by tripping.
The "I
e
upper limit value violation" or "I
e
lower limit value violation" message is issued. If the
current exceeds the maximum rated operational current by a factor of ten, the motor starter
shuts down the motor even if the current limit values are deactivated. An entry in the logbook
(data set 73 (Page 182)) is generated.
Example
The following example shows an application for the upper and lower current limit:
●
The viscosity of the mixed mass is too high, that is, the upper current limit has been
overshot.
●
No load because drive belt is broken. In other words, the lower current limit has been
violated.
Note
The parameterized current warning thresholds are not activated until the CLASS time
expires.
Setting ranges
The table below shows the possible setting range for the lower and upper current warning
limits:
Device parameters
Default setting
Setting range
Lower current limit
Deactivated
•
18.75 ... 100 % of I
e
•
0 % (= deactivated)
Increment: 3.125 %
Upper current limit
Deactivated
•
50 to 400 % of I
e
•
0 % (= deactivated)
Increment: 3.125 %
