270 ACQ550-U1 User’s Manual
Technical data
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 8 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 8 kHz switching frequency (see section Switching frequency derating
on page 270).
Referring to I
2N
in the ratings tables (starting from page 267), the following drives
exceed the I
2N
requirement of 19.25 A: ACQ550-x1-023A-4, or ACQ550-x1-024A-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 · 10 °C
= 90% or 0.90.
The output current is then 0.90 · I
2N
or 0.90 · I
2hd
.
Altitude derating
In altitudes 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 V 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),
• derate all rated currents and powers (including drive’s overload currents) to 80%.
When using the 12 kHz switching frequency (parameter 2606),
• derate all rated currents and powers (including drive’s overload currents) to 65%
(to 50% for 600 V, R4 frame sizes, that is for ACQ550-U1-032A-6 … ACQ550-U1-
062A-6),
• derate ambient temperature maximum to 30 °C (86 °F).
• Note: The continuous maximum current is limited to I
2hd
.
Note: Setting parameter 2607
SWITCH FREQ CTRL = 1 (ON) allows the drive to reduce
the switching frequency if/when the drive’s internal temperature exceeds 80 °C (with
12 kHz switching frequency) or 90 °C (with 8 kHz switching frequency). See the
parameter description for 2607 for details.
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