Nord Drivesystems SK 510P - Reduced Output Power; Increased Heat Dissipation Due to Pulse Frequency; Figure 13: Heat Losses Due to Pulse Frequency

8 Additional information
BU 0600 en-2319 205
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
163 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 13: Heat losses due to pulse frequency