Lenze 9400 Manual - Manual (Page 75)

Single-axis controllers
Rated data (devices for 400/500V mains)
Current-time diagrams
4

75 EDS94SPP101 EN 7.1
4.3.7 Current-time diagrams
In addition to the data for overcurrent operation within the 5-s cycle or 3-min cycle, here
you are provided with information on the dimensioning of application-oriented cycles.
By means of the following information you determine permissible load periods with
overcurrents and required recovery times with limited currents. If the currents and times
determined are observed, the Ixt monitoring function for the protection of the devices will
not respond.
Characteristics
The following characteristics (”Current-time diagrams”) describe the device utilisation via
amperage and the duration of current flow.
The left part of the diagram (negative time data) represents the overload phase, while the
right part of the diagram (positive time data) shows the relieving phase.
Devices with an identical Ixt behaviour are combined within a diagram. A second diagram
enlarges a cutout area to improve the clearness of display.
Requirements
ƒ Switching frequency
The curves shown always refer to the variable rated switching frequency (f
chopp
) at
which the rated device current is permissible permanently. As this rated switching
frequencies are different for the individual devices, they are specified with the
diagrams. This means that the switching frequency is reduced automatically during
the overload phase. During the recovery phase the switching frequency set is
maintained.
ƒ Mains voltage
In the diagrams a mains voltage of U
N
= 400 V was assumed. Where applicable, a
current derating depending on the mains voltage may be necessary for the devices,
depending onthe switching frequency that is reached. Thismeans thatthe currentsare
weighted differently in the Ixt monitoring. The devices for which a derating is required
can be gathered from the ”Rated values” section. The continuous currents specified
there then are the 100% values which are required for working with the diagrams.
ƒ Ambient temperature
The ambient temperature may be maximally T
Amb
< 45 °C. In the case of higher
ambient temperatures the reduced continuous currents have to be taken into
consideration.
ƒ Output frequency
In the diagrams an output frequency (= field frequency) f
out
> 5 Hz has been assumed.
In the case of smaller output frequencies (f
out
= 0 … 5 Hz), a different switching
frequency results in a different device utilisation due to a different continuous current.
When the diagrams were created, this device behaviour was not taken into
consideration.
If a fixed switching frequency f > 4 kHz is selected, the reduction of the permissible
continuous current has to be considered (100 % = reduced continuous current) for
smaller output frequencies (f
out
= 0 … 5 Hz).