Procon V3D Series, Руководство программиста

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H - I - J
PROGRAMMER’S MANUAL
V8.94.11-
- 54 -
The motor current vs. time
I
max
=I
n
∙current limit
e.g.:
I
n
=4 A
current limit=120 %
I
inv.max
=9 A
I
max
=4 A ∙1,2=4,8 A
I
̂
max
=4,8∙
√
2=6,79 A
Since
I
inv.max
>I
̂
max
, if necessary even this
current can develop.
Permissible steady motor current vs. frequency
If the motor has its own cooling only, to avoid
overheating, it can only be loaded with a
portion of its nominal current as given in the
graph in the function of the frequency!
With forced cooling the motor can be loaded
with its nominal current in the whole
frequency range.
The effect of the ambient temperature can be
taken into consideration using the heat limit.
E.g. the 120% heat limit puts each point of the
curve upwards by 20%.
Permissible motor overcurrent vs. time
a motor power below 3kW
b motor power between 3 kW and 20kW
c motor power above 20kW
In case of forced cooling, for the time given
in the graph the motor can be loaded with a
current higher than the nominal current,
without overheating!
The effect of the ambient temperature can
be taken into consideration using the heat
limit.
E.g. the 120% heat limit puts each point of
the curve upwards by 20%.
In case of own cooling, this curve will modify
in function of the frequency according to the
previous graph
t
I
frequency
modification
overload
I
inv.max
I
max
I
n
I
motor
I
70%
n
I
n
f [Hz] f /15
n
f /2
n
f
n
forced cooling
own cooling
T [min]
1 2 3 4 5 10
I
motor
4xI
n
3xI
n
2xI
n
I
n
a b c