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GENERAL ELECTRICAL DATA
3.3 General electrical data
3.3.1 Switching frequency and temperature
The drive controller cooling is designed by way that the heat sink overtemperature
threshold is not exceeded at rated conditions. A switching frequency higher than the rat-
ed switching frequency also produces higher losses and thus a higher heat sink heating.
If the heat sink temperature reaches a critical threshold (T
DR), the switching frequency
can be reduced automatically step by step. This prevents that the drive controller switch-
esoduetooverheatingoftheheatsink.IftheheatsinktemperaturefallsbelowTUR,
the switching frequency is increased back to the setpoint. At temperature TEM the switch-
ing frequency is immediately reduced to rated switching frequency. "Derating“ must be
activated, for this function to work.
Device size 21 22 23 24
Rated switching frequency
1)
fSN / kHz 8 4 2 4 8 2 4
Max. switching frequency
1)
fS_max / kHz 16
Min. switching frequency
1)
fS_min / kHz 1.25
Max. heat sink temperature T
HS/°C 90 90 95 67 95 87
Temperature for derating the switching
frequency
T
DR/°C 84 84 85 57 85 77
Temperature for uprating the switching
frequency
T
UR/°C 70 70 75 50 75 67
Temperature for switching to rated switching
frequency
T
EM/°C 87 87 90 62 90 82
Table 23: Switching frequency and temperature of the 400 V devices
1)
The output frequency should be limited in such a way that it does not exceed 1/10 of the switching frequen-
cy.
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