ACH550-UH User’s Manual 227
Technical Data
Derating
The load capacity (current and power) decreases if the installation site altitude
exceeds 1000 meters (3300 ft), or if the ambient temperature exceeds 40 °C
(104 °F) or if 8 kHz switching frequency (parameter 2606) is used.
Temperature Derating
In the temperature range +40 °C…50 °C (+104 °F…122 °F) the rated output current
is decreased 1% for every 1 °C (1.8 °F) above +40 °C (+104 °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%/°C x 10 °C
= 90% or 0.90.
The output current is then 0.90 x I
2N
.
Altitude Derating
In altitudes from 1000…4000 m (3300…13,200 ft) above sea level, the derating is 1%
for every 100 m (330 ft). If the installation site is higher than 2000 m (6600 ft) above
sea level, please contact your local ABB distributor or office for further information.
Single Phase Supply Derating
For 208…240 Volt series drives, a single phase supply can be used. In that case, the
derating is 50%.
Switching Frequency Derating
If the 8 kHz switching frequency (parameter 2606) is used, either:
• Derate P
N
and I
2N
to 80% or
• Set parameter 2607 SW FREQ CTRL = 1 (ON) which allows the drive to reduce the
switching frequency if/when the drive’s internal temperature exceeds 90
°C. See
the parameter description for 2607 for details.
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