Description of the Software Modules and Parameters
Parameter manual
b maXX
BM5800
Document No.: 5.16029.03
717
3
The maximum thermal load of the motor and motor operating temperature
In general the maximum thermal load corresponds to the maximum permissible continu-
ous temperature of the winding. The maximum load however can be limited by other fac-
tors.
The maximum permissible continuous temperature of the winding depends on the insu-
lation class of the motor. It results from the permissible temperature increase plus a
hotspot safety margin and refers to a specified maximum environmental temperature of
40°C. The maximum continuous temperature NEMA motor insulation class F is specified
with 155°C, for example.
The steady-state temperature of the motor at a maximum admitted continuous current
load (such as the acquired motor temperature) cannot be predetermined. The continuous
current load of the motor can determine the environmental temperature, insulation class,
production tolerances and the cooling type etc. Therefore, the error 205 "Motor I2t-over-
load" can occur even though a motor temperature actual value is lower than the permitted
continuous temperature of the winding. Refer to the motor manufacturer for details (such
as the temperature measurement).
I
2
t-Monitoring
Figure 187:
Motor I
2
t overload monitoring (standard solution)
The motor overload monitoring is active if the motor l
2
ent from zero.
If the motor l
2
t actual value at activated motor overload monitoring reaches the l
2
t warning
limit
, the motor warning number 219 "l2t warning limit exceeded" is displayed.
The warning is withdrawn by a fixed hysteresis of 10% under the warning threshold. If the
warning threshold is 0 no warning occurs.
As soon as the l
2
t actual value reaches the threshold
the pulse inhibit is activated
and the motor error 205 "l2t overload" is displayed.
+
-
N
D
N
D
=0
0%
=0
Ref
I
PT1
6.28
5000_0356_rev03_e
1 / (155°C-40°C)
0
40°C
T
t
6.29
6.39
N
I ,107.9
Motor I t actual value
2
Warnung no. 219
I t warning
threshold
exceeded
2
Error no. 205
I t overload
2
Motor
I2t time constant
107.28
Motor total current
smoothed, Iact
6.30
Motor temperature
Tm 128.3
Motor nominal current
Drive status = 0,
or activation: 107.28 from 0 to = 0
I t threshold
2
I t warning threshold
2
Motor
I t time constant
107.28
2
Initialization
Iact
I values
2
10% hysteresis
