220
System Manual – MOVIDRIVE® compact Drive Inverters
4
Overload capacity of the inverter
Project Planning
Overload capac-
ity in minutes
This is the overload capacity that corresponds to at least a quarter of the heat sink time
constant (0.25 T). The overload usually lasts a few minutes. The overload capacity can
be determined as follows:
Overload time t
1
≥
0.25
×
T
→
determine using the diagrams
Example
Overload times t
1
≥
0.25
×
T:
The time axis is separate. The left part shows the overload time t
1
and the right part the
low-load time t
2
. The temperature profile of the maximum permitted overload current I
out
1
is shown above t
1
for the corresponding peripheral conditions. The temperature pro-
files of the various low-load currents I
out 2
are shown in a series of curves above t
2
.
Using the sample data above and the load cycle from Figure 62 the overload capacity
(
→
Fig. 64) is determined as follows:
•
At overload time t
1
= 0.75
×
T move vertically upwards until the point of intersection
with I
out 1
.
•
Move horizontally to the right until the point of intersection with I
out 2
= 0.4
×
I
D
.
•
Move vertically downwards and read the minimum low-load time t
2
→
t
2
= 1.25
×
T.
All times t
2
to the right of the point of intersection with I
out2
are permissible (
√
); all times
t
2
to the left are not (!).
In the load cycle from Figure 62 t
2
= 1.5
×
T, which means the overload capacity is given.
For overload times t
1
< 0.25
×
T, the reading accuracy of the diagrams is inadequate.
The curves in this area are almost linear. This means you can use a linear formula for
overload times t
1
< 0.25
×
T instead of the diagrams.
For overload times t
1
≥
0.25
×
T use the following diagrams to ascertain the overload
capacity. Note the dependencies of I
D
on I
N
as shown in Figure 63 .
56693AXX
Figure 64: Sample overload diagram
1
t [T]
1
t [T]
2
120%
I
D
60 % I
D
40 % I
D
20 % I
D
0 % I
D
1.25
0.75
I
out 2
I
out 1
V =
1
3 x AC 400 V
amb
PWM
=
f
(P860 / P861) =
40 °C
4 kHz
!
ϑ
1.5
2
1
0.5
0
0.5
1.5
2
2.5
3
3.5
4
4.5
5
✓
Summary of Contents for MOVIDRIVE compact MCH41A
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