Design Guide | VLT® AutomationDrive FC 360
7.11 Acoustic Noise
The acoustic noise from the drive comes from 3 sources:
l DC intermediate circuit coils.
l Internal fans.
l RFI filter choke.
The following table lists the typical acoustic noise values measured at a distance of 1 m (3.3 ft) from the unit.
Table 15: Acoustic Noise
Enclosure size dBA at full fan speed
J8 73
J9 75
Test results performed according to ISO 3744 for audible noise magnitude in a controlled environment. Noise tone has been quantified
for engineering data record of hardware performance per ISO 1996-2 Annex D.
7.12 dU/dt Conditions
NOTICE
To avoid the premature aging of motors that are not designed to be used with drives, such as those motors without phase
insulation paper or other insulation reinforcement, Danfoss strongly recommends a dU/dt filter or a sine-wave filter fitted on the
output of the drive. For further information about dU/dt and sine-wave filters, see the Output Filters Design Guide.
When a transistor in the inverter bridge switches, the voltage across the motor increases by a dU/dt ratio depending on the motor cable
(type, cross-section, length shielded or unshielded) and the inductance.
The natural induction causes an overshoot U
PEAK
in the motor voltage before it stabilizes itself at a level depending on the voltage in the
DC link. The rise time and the peak voltage U
PEAK
affect the service life of the motor. In particular, motors without phase coil insulation
are affected if the peak voltage is too high. Motor cable length affects the rise time and peak voltage. If the motor cable is short (a few
meters), the rise time and peak voltage are lower. If the motor cable is long (100 m (328 ft)), the rise time and peak voltage are higher.
Peak voltage on the motor terminals is caused by the switching of the IGBTs. The drive complies with the demands of IEC 60034-25:2007
edition 2.0 regarding motors designed to be controlled by drives. The drive also complies with IEC 60034-17:2006 edition 4 regarding
Norm motors controlled by drives.
High-power range
The power sizes in the following tables at the appropriate mains voltages comply with the requirements of IEC 60034-17:2006 edition 4
regarding normal motors controlled by drives, IEC 60034-25:2007 edition 2.0 regarding motors designed to be controlled by drives, and
NEMA MG 1-1998 Part 31.4.4.2 for inverter-fed motors. The power sizes in the following tables do not comply with NEMA MG 1-1998 Part
30.2.2.8 for general purpose motors.
Danfoss A/S © 2024.01 AJ435824192086en-000101 / 130R1295 | 65
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