Rfi Switch - Danfoss VLT AutomationDrive FC 300 Design Manual
90–1200 kw
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Also See for VLT AutomationDrive FC 300:
- Programming manual (277 pages) ,
- Design manual (275 pages) ,
- Operating instructions manual (169 pages)
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Electrical Installation
PLC
PE
PE
1
2
Figure 7.59 Equalizing Cable next to a Control Cable
1
Min. 0.025 in
2
[16 mm
2
]
2
Equalizing cable
Table 7.72 Legend to Figure 7.59
50/60 Hz Ground Loops
With very long control cables, ground loops may occur.
Eliminate ground loops by connecting one end of the
shield-to-ground with a 100nF capacitor (keeping leads
short).
PLC
PE
100nF
Figure 7.60 Eliminating Ground Loops by Connecting Ground
to 100nF Capacitor
Avoid EMC Noise on Serial Communication
This terminal is grounded via an internal RC link. Use
twisted-pair cables to reduce interference between
conductors. The recommended method is shown in
Figure 7.62.
FC
69
68
61
PE
PE
2
Figure 7.61 Using Twisted Pair Cables to Reduce Interference
1
Min. 0.025 in
2
[16 mm
2
]
2
Equalizing cable
Table 7.73 Legend to Figure 7.61
MG34S222
Design Guide
FC
PE
<10 mm
PE
FC
PE
<10 mm
FC
69
68
61
PE
<10 mm
PE
1
Danfoss A/S © Rev. 2014-02-10 All rights reserved.
Alternatively, the connection to terminal 61 can be
omitted:
FC
69
68
PE
PE
1
2
Figure 7.62 Reducing Interference by Omitting Terminal 61
1
2
2
Min. 0.025 in
[16 mm
]
2
Equalizing cable
Table 7.74 Legend to Figure 7.62
7.8.4 RFI Switch
Line Power Supply Isolated from Ground
If the adjustable frequency drive is supplied from an
isolated line power source (IT line power, floating delta, or
grounded delta) or TT/TN-S line power with grounded leg,
the RFI switch is recommended to be turned off (OFF)
14-50 RFI 1 on the adjustable frequency drive and 14-50 RFI
1 on the filter. For more detail, see IEC 364-3. In OFF, the
filter capacitors between the chassis and the intermediate
circuit are cut off to avoid damage to the intermediate
circuit and to reduce the ground capacity currents
(according to IEC 61800-3).
If optimum EMC performance is needed or parallel motors
are connected or the motor cable length is above 80 ft [25
m], Danfoss recommends setting the 14-50 RFI 1 to [ON].
Refer also to the Application Note, VLT on IT Line Power,
MN50P. It is important to use isolation monitors that are
capable for use together with power electronics (IEC
61557-8).
FC
68
69
PE
<10 mm
PE
1)
via
237
7
7
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