The derating factor for 4921 ft (1500 m) is 1 - 1/10 000 m · (1500 - 1000) m = 0.95.
The derated drive output current becomes I
Ld
= 0.95 · 52 A = 49.4 A.
3.
Surrounding air temperature derating, IP21 (UL Type 1) (page 242):
The derating factor for 50 °C ambient temperature = 0.90.
The derated drive output current becomes then I
Ld
= 0.90 · 49.4 A = 44.46 A.
Example 2, IEC: How to calculate the required drive
If your application requires continuous 12.0 A of motor current (I
2
) at 8 kHz switching
frequency, the supply voltage is 400 V and the drive is situated at 1500 m altitude and
at 35 °C ambient temperature, calculate the appropriate IP21 / (UL Type 1) drive size
requirement as follows:
1.
Switching frequency derating by derating factor (page 246):
The minimum size required is I
2
= 12.0 A / 0.65 = 18.46 A,
where 0.65 is the derating for 8 kHz switching frequency (frames R2…R3).
2.
Altitude derating (page 245):
The derating factor for 1500 m is 1 - 1/10 000 m · (1500 - 1000) m = 0.95.
The minimum size required becomes then I
2
= 18.46 A / 0.95 = 19.43 A.
3.
Surrounding air temperature derating, IP21 (UL Type 1) (page 242):
No derating needed for 35 °C ambient temperature.
Referring to I
2
in the ratings tables (starting from page 232), drive type
ACH580-01-01-026A-4 exceeds the I
2
requirement of 19.43 A.
Example 2, UL (NEC): How to calculate the required drive
If your application requires continuous maximum current with 10% overload 12.0 A of
motor current (I
Ld
) at 8 kHz switching frequency, the supply voltage is 480 V and the
drive is situated at 4921 ft (1500 m) altitude and at 35 °C ambient temperature, calculate
the appropriate IP21 / UL Type 1 drive size requirement as follows:
1.
Switching frequency derating by derating factor (page 246):
The minimum size required is I
Ld
= 12.0 A / 0.65 = 18.46 A,
where 0.65 is the derating for 8 kHz switching frequency (frames R2…R3).
2.
Altitude derating (page 245):
The derating factor for 4921 ft (1500 m) is 1 - 1/10 000 m · (1500 - 1000) m = 0.95.
The minimum size required becomes then I
Ld
= 18.46 A / 0.95 = 19.43 A.
3.
Surrounding air temperature derating, IP21 (UL Type 1) (page 242):
No derating needed for 35 °C ambient temperature.
Referring to I
LD
in the ratings tables (starting from page 236), drive type
ACH580-01-01-026A-4 exceeds the I
Ld
requirement of 19.43 A.
Technical data 241
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