ABB FOCH, Hardware Manual, Page: 28 / 38

Derating
The load capacity (current and power) decreases if the installation site altitude exceeds
1000 metres (3281 ft), or if the ambient temperature exceeds 40 °C (104 °F).
Temperature derating:
In the temperature range +40 °C (+104 °F) to +50 °C (+122 °F), the rated output current
is decreased 1% for every additional 1 °C (1.8 °F). The output current is calculated by
multiplying the current given in the rating table by the derating factor.
Example:
If the ambient temperature is 50 °C (+122 °F), the derating factor is 100% - (1 % / 1 °C)
· 10 °C = 90% or 0.90. The output current is then 0.90 ·
I
thmax
. For I
thmax
, see maximum
values table on page 12.
Altitude derating:
At altitudes from 1000 to 4000 m (3281 to 13123 ft) above sea level, the derating is 1%
for every 100 m (328 ft). For a more accurate derating, use the DriveSize PC tool. The
value calculated for the drive applies also to its d
u/dt filter.
Maximum drive output frequency: 120 Hz
Maximum allowed average switching frequency:
3 kHz (converter units with supply voltage < 500 V and 500 V) or 2 kHz (converter units
with supply voltage > 500 V)
Change the switching frequency with a drive parameter. If there is no such parameter
in the drive software, apply the settings to be used with long motor cables. For example,
for the ACS880 drive, bit 13 of parameter 95.20 HW options word 1 must be switched
on. The setting enables an overtemperature protection for the filter. For further
information, see the appropriate firmware and hardware manuals.
Maximum cable length between the drive output and the filter: 3 m
Applicable standards and markings: EN 60204-1, EN 60529, EN 61800-5-1, EN 50178,
UL listed in UL E211945, CSA certified in Certificate 206573, CE marking, UL approved
insulation system.
28 Technical data