Danfoss VLT HVAC Drive FC 100 Series, Руководство по конструкции

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3. RFI filter choke.
Typical values are measured at a distance of 3.28 ft. [1 m]
from the unit:
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 59.4 70.5
B4 53 62.8
C1 52 62
C2 55 65
C3 56.4 67.3
C4 - -
D1/D3 74 76
D2/D4 73 74
E1/E2* 73 74
** 82 83
F1/F2/F3/F4 78 80
* 425 hp [315kW], 380–480V AC and 600–675 [450–500kW], 525–
690V AC only.
** Remaining E1/E2 power sizes.
*** For D, E and F sizes, reduced fan speed is at 87%, measured
at 200V.
Table 8.16
8.5 Peak voltage on motor
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 non-shielded)
- 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 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, motors
without phase coil insulation are especially affected. If the
motor cable is short (by a few yards), the rise time and
peak voltage are lower.
If the motor cable is long (328 ft [100 m]), the rise time
and peak voltage increases.
In motors without phase insulation paper or other
insulation reinforcement suitable for operation with
voltage supply (such as a Adjustable frequency drive), fit a
sine-wave filter on the output of the Adjustable frequency
drive.
To obtain approximate values for cable lengths and
voltages not mentioned below, use the following rules of
thumb:
1. Rise time increases/decreases proportionally with
cable length.
2. U
PEAK
= DC link voltage x 1.9
(DC link voltage = AC line voltage x 1.35).
3.
dU
/
dt =
0.8 × UPEAK
Risetime
Data are measured according to IEC 60034-17.
Cable lengths are in meters.
Adjustable Frequency Drive, P5K5, T2
Cable
length (ft [m])
AC line
voltage [V]
Rise time
[
μ
sec]
Vpeak
[kV]
dU/dt
[kV/
μ
sec]
118.1 [36] 240 0.226 0.616 2.142
164 [50] 240 0.262 0.626 1.908
328 [100] 240 0.650 0.614 0.757
492.1 [150] 240 0.745 0.612 0.655
Table 8.17
General Specifications and ...
VLT
®
HVAC Drive Design Guide
8-22 MG11BB22 - VLT
®
is a registered Danfoss trademark
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