218
System Manual – MOVIDRIVE® compact Drive Inverters
4
Overload capacity of the inverter
Project Planning
Example
Sample load cycle:
•
Overload current I
out 1
= 120 % I
D
•
Low-load current I
out 2
= 40 % I
D
•
Overload time t
1
= 0.75
×
T
•
Low-load time t
2
= 1.5
×
T
Continuous out-
put current
The thermal model in MOVIDRIVE
®
implements dynamic limiting of the maximum out-
put current. The maximum continuous output current I
D
is dependent on the PWM cycle
frequency, the ambient temperature
ϑ
amb
and the output frequency f
A
.
It is particularly important to take output frequencies f
A
< 2 Hz into account for:
•
Electrically stopping hoists
•
Torque control at low speeds or at a standstill
05550AXX
Figure 62: Sample load cycle
NOTE
The output frequency of the inverter when used with asynchronous motors is made up
of the rotational frequency (
Ⳏ
speed) and the slip frequency. With synchronous
motors, the output frequency of the inverter is the same as the rotational frequency of
the synchronous motor.
Содержание MOVIDRIVE compact MCH41A
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