1. Switching frequency derating by derating factor (page 283):
No derating needed for 4 kHz.
2. Altitude derating (page 282):
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 279):
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 283):
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 282):
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 279):
No derating needed for 35 °C ambient temperature.
Referring to
I
2
in the ratings tables (starting from page 268), drive type
ACS580-01-026A-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 283):
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 282):
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 279):
278 Technical data