NORDAC BASE (SK 180E / SK 190E) – Users Manual for Frequency Inverters
186
BU 0180 en-4118
8.4 Reduced output power
The frequency inverters are designed for certain overload situations. For example, 1.5x overcurrent
can be used for 60 s. For approx. 3.5 s a 2x overcurrent is possible. A reduction of the overload
capacity or its time must be taken into account in the following circumstances:
• Output frequencies < 4.5 Hz and constant voltages (needle stationary)
• Pulse frequencies greater than the nominal pulse frequency (P504)
• Increased mains voltage > 400 V
• Increased heat sink temperature
On the basis of the following characteristic curves, the particular current / power limitation can be read
off.
8.4.1 Increased heat dissipation due to pulse frequency
This illustration shows how the output current must be reduced, depending on the pulse frequency for
230V and 400V devices, in order to avoid excessive heat dissipation in the frequency inverter.
For 400V devices, the reduction begins at a pulse frequency above 6kHz. For 230V devices, the
reduction begins at a pulse frequency above 8kHz.
The diagram shows the possible current load capacity for continuous operation.
1.2
0.4
k 400V f puls
k 230V f puls
16
3
f puls
4
6
8
10
12
14
16
0.4
0.5
0.6
0.7
0.8
0.9
1
1.1
1.2
I / I
N
Pulse frequency [kHz]
Figure 18: Heat losses due to pulse frequency
Summary of Contents for SK 180E Series
Page 1: ...BU 0180 en NORDAC BASE SK 180E SK 190E Users Manual for Frequency Inverters...
Page 4: ...NORDAC BASE SK 180E SK 190E Users Manual for Frequency Inverters 4 BU 0180 en 4118...
Page 185: ...8 Additional information BU 0180 en 4118 185 8 3 4 EU Declaration of Conformity...
Page 211: ...Key word index BU 0180 en 4118 211...
Page 212: ...6071802 4118...
