Switching frequency derating: Derating is not necessary at 4 kHz.
Altitude derating: The derating factor for 1500 m is
Surrounding air temperature derating: According to the temperature derating
table, the derating factor of 17A0-4 drive's nominal output current at 55 °C
surrounding air temperature is 0.95.
Multiply the nominal drive output current by all the applicable derating factors. In
this example, the derated output current becomes
Example 1, UL (NEC): How to calculate the derated current
The drive type is ACS180-04x-17A0-4, which has light-duty output current (
I
Ld
) of
14 A at 480 V. Calculate the derated output current at 4 kHz switching frequency,
at 6000 ft altitude and at 131 °F surrounding air temperature.
Switching frequency derating: Derating is not necessary at 4 kHz.
Altitude derating: The derating factor for 6000 ft is
Surrounding air temperature derating: According to the temperature derating
table, the derating factor of 17A0-4 drive's light-duty output current at 131 °F
surrounding air temperature is 0.95.
Multiply the drive output current by all the applicable derating factors. In this
example, the derated output current becomes
Example 2, IEC: How to calculate the required drive
The application requires a nominal motor current of 6.0 A at a switching frequency
of 8 kHz. The supply voltage is 400 V, the altitude is 1800 m and the surrounding
air temperature is 35 °C.
Altitude derating: The derating factor for 1800 m is
Surrounding air temperature derating: Derating is not necessary at 35 °C
surrounding air temperature.
To see if the derated output current of a drive is sufficient for the application,
multiply the nominal output current (
I
n
) by all the applicable derating factors. For
example, drive type ACS180-04x-12A6-4 has a nominal output current of 12.6 A at
400 V. The switching frequency derating factor for this drive type is 0.68 at 8 kHz.
Calculate the derated drive output current:
102 Technical data
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