Safety instructions
Thermal motor monitoring
Self−ventilated motors
26
EDBCSXS064 EN 4.0
Calculate release time and I
2
x t load
Calculate the release time and the I
2
x t load of the motor considering the values in
C0129/1
and
C0129/2
(evaluation coefficient "y").
Formulae for release time
Information
y
+
100%
*
C0129
ń
1
C0129
ń
2
n
n
N
)
C0129
ń
1
T
+ *
(
t
)
ln
ȧȧ
ȡ
Ȣ
1
*
z
)
1
ǒ
IMot
y
IN
Ǔ
2
100
ȧȧ
ȣ
Ȥ
T
Release time of the I
2
x t monitoring
t
Thermal motor time constant (C0128)
In
Function: Natural logarithm
I
Mot
Actual motor current (C0054)
I
r
Rated motor current (C0088)
z
Threshold value in C0120 (OC6) or C0127 (OC8)
y
Evaluation coefficient
n
rated
Rated speed (C0087)
Formulae for I
2
x t load
Information
L(t)
+
ǒ
I
Mot
y
I
N
Ǔ
2
100%
ǒ
1
*
e
*
t
t
Ǔ
L(t)
Chronological sequence of the I
2
x t load of the motor
(Display: C0066)
y
Evaluation coefficient
I
Mot
Actual motor current (C0054)
Ir
Rated motor current (C0088)
t
Thermal motor time constant (C0128)
If the controller is inhibited, the I
2
x t load is reduced:
L(t)
+
L
Start
e
*
t
t
Ǹ
L
Start
I
2
x t load before controller inhibit
If an error is triggered, the value corresponds to the
threshold value set in C0120 (OC6) or C0127 (OC8).
