Lenze 8400 BaseLine D - Manual (Page 106)

5 Motor control (MCTRL)
5.8 Monitoring
106
Lenze · 8400 BaseLine D · Reference manual · DMS 5.5 EN · 01/2014 · TD05
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[5-5] Tripping characteristic of the I 2 xt monitoring
Example:
C120 = I
r
/I
rated
x 100 %
C054 = 150 % rated motor current
• After approx. 60 seconds, C066 has reached the final value100 % at output frequencies
f > 40 Hz.
• The controller outputs the " OC6: I2xt overload motor" error message and triggers the response
set in C606 (default setting: "Warning").

Tip!
• If forced ventilated motors are used, a premature response of the overload threshold can
be avoided by deactivating this function if necessary ( C606 = "0: No Reaction").
• The current limits set in C022 and C023 influence the I 2 xt calculation only in an indirect
way. However, the operation of the motor at maximum possible load can be averted.
 Defining current and speed limits ( 77)
f: Output frequency
t: Release time
I
rated
: Rated controller current at a switching frequency of f = 8 kHz
I
r
: Rated motor current (see nameplate of motor)
C054 : Apparent motor current
C120 : Motor overload threshold
60
180
240
300
360
t [s]
0.5 0
0
1.0 1.5 2.0 C00054
I
r
120
f = 0 Hz
f = 20 Hz
f > 40 Hz
I x 100 %
I
r
N
C00120 <
I x 100 %
I
r
N
C00120 =
I x 100 %
I
r
N
C00120 >