Enclosure At reduced fan speed (50%) [dBA] *** Full fan speed [dBA]
A2 51 60
A3 51 60
A5 54 63
B1 61 67
B2 58 70
B3 - -
B4 --
C1 52 62
C2 55 65
C3 - -
C4 --
D1+D3 74 76
D2+D4 73 74
E1/E2 * 73 74
E1/E2 ** 82 83
* 315 kW, 380-480 VAC and 355 kW, 525-600 VAC only!
** Remaining E1+E2 power sizes.
*** For D and E sizes, reduced fan speed is at 87%, measured at 200 V.
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 screened or unscreened)
- inductance
The natural induction causes an overshoot U
PEAK
in the motor voltage before it stabilises itself at a level depending on the voltage in the intermediate
circuit. The rise time and the peak voltage U
PEAK
affect the service life of the motor. If the peak voltage is too high, especially motors without phase coil
insulation are affected. If the motor cable is short (a few metres), the rise time and peak voltage are lower.
If the motor cable is long (100 m), the rise time and peak voltage are higher.
In motors without phase insulation paper or other insulation reinforcement suitable for operation with voltage supply (such as a frequency converter),
fit a du/dt filter or a sine-wave filter on the output of the frequency converter.
10. Specifications
VLT
®
AQUA Drive
Operating Instructions
162
MG.20.M5.02 - VLT
®
is a registered Danfoss trademark
10
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