ABB ACH550 - Full Version - Enervex

1-302 ACH550-UH User’s Manual
Derating
The load capacity (current and power) decreases for certain situations, as defined
below. In such situations, where full motor power is required, oversize the drive so
that the derated value provides sufficient capacity.
For example, if your application requires 15.4 A of motor current and a 12 kHz
switching frequency, calculate the appropriate drive size requirement as follows:
The minimum size required = 15.4 A / 0.80 = 19.25 A
Where: 0.80 is the derating for 12 kHz switching frequency (see Switching frequency derating
below).
Referring to I 2n in the ratings tables (page 1-299), the following drives exceed the I 2n
requirement of 19.25 A: ACH550-UH-023A-4, or ACH550-UH-024A-2
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). Calculate the
output current 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
When using 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.
When using the 12 kHz switching frequency (parameter 2606) is used, either:
• Derate:
– P n and I 2n to 65% (to 50% for 600 V R4 frame sizes, that is for
ACH550-xx-032A-6…ACH550-xx-062A-6), and
– Ambient temperature maximum to 30 °C (86 °F), 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 80 °C. See
the parameter description for 2607 for details.
Technical data