- Control cables must be screened/armoured.
Use a clamp from the accessory bag to connect
the screen to the CD 302 decoupling plate for
control cables.
Generally speaking, control cables must be
braided screened/armoured and the screen must
be connected by means of a cable clamp at both
ends to the metal cabinet of the unit.
The drawing indicates how correct earthing is
carried out and what to do if in doubt.
a. Correct earthing
Control cables and cables for serial communica-
tion must be fitted with cable clamps at both ends
to ensure the best possible electrical contact.
b. Wrong earthing
Do not use twisted cable ends (pigtails). They in-
crease the screen impedance at high frequencies.
c. Protection with respect to earth potential
between PLC(Program Logic Controller) and
CD 302
If the earth potential between the frequency
converter and the PLC (etc.) is different, electric
noise may occur that will disturb the entire sys-
tem. Solve this problem by fitting an equalising
cable, next to the control cable. Minimum cable
cross-section: 16mm2.
d. For 50/60 Hz earth loops
If very long control cables are used, 50/60 Hz
earth loops may occur. Solve this problem by
connecting one end of the screen to earth via a
100nF capacitor (keeping leads short).
e. Cables for serial communication
Eliminate low-frequency noise currents between
two frequency converters by connecting one
end of the screen to terminal 61. This terminal
is connected to earth via an internal RC link. Use
twisted-pair cables to reduce the differential
mode interference between the conductors.
SPS etc.
SPS etc.
SPS etc.
Min. 16mm
2
Ausgleichskabel
SPS etc.
/TYSK
PE
FC
PE
MONT. AF KABEL.
100%
04 01 20
130BA051.11
130BA051.11
PE
PE
FC
PE
PE
FC
100nF
PE
FC
69
FC
PE
PE
PE
68
61
68
69
FC
PE
a
b
c
d
e
• Safe Stop Installation
To carry out an installation of a Category 0 Stop
(EN60204) in conformance with Safety Category
3 (EN954-1), follow these instructions:
1. The bridge (jumper) between Terminal 37 and
24 V DC of CD 302 must be removed. Cutting or
breaking the jumper is not sufficient. Remove it
entirely to avoid short-circuiting. See jumper on
illustration.
2. Connect terminal 37 to 24 V DC by a short-cir-
cuit protected cable. The 24 V DC voltage supply
must be interruptible by an EN954-1 Category 3
circuit interrupt device. If the interrupt device and
the frequency converter are placed in the same
installation panel, you can use a regular cable
instead of a protected one.
• Electrical Installation - EMC protection
The following is a guideline to good engineering
practice when installing frequency converters.
Follow these guidelines to comply with EN
61800-3 First environment. If the installation is
in EN 61800-3 Second environment, i.e. indus-
trial networks, or in an installation with its own
transformer, deviation from these guidelines is
allowed but not recommended. See also paragra-
phs CE Labelling, General Aspects of EMC Emis-
sion and EMC Test Results.
Good engineering practice to ensure EMC-cor-
rect electrical installation:
- Use only braided screened/armoured motor
compressor cables and braided screened/armou-
red control cables. The screen should provide a
minimum coverage of 80%. The screen material
must be metal, not limited to but typically cop-
per, aluminium, steel or lead. There are no special
requirements for the mains cable.
- Installations using rigid metal conduits are not
required to use screened cable, but the motor
compressor cable must be installed in conduit
separate from the control and mains cables. Full
connection of the conduit from the drive to the
motor compressor is required. The EMC perfor-
mance of flexible conduits varies a lot and infor-
mation from the manufacturer must be obtained.
- Connect the screen/armour/conduit to earth at
both ends for motor compressor cables as well as
for control cables.
In some cases, it is not possible to connect the
screen in both ends. If so, connect the screen
at the frequency converter. See also Earthing of
Braided Screened/Armoured Control Cables.
- Avoid terminating the screen/armour with
twisted ends (pigtails). It increases the high
frequency impedance of the screen, which re-
duces its effectiveness at high frequencies. Use
low impedance cable clamps or EMC cable glands
instead.
- Avoid using unscreened/unarmoured motor
compressor or control cables inside cabinets hou-
sing the drive(s), whenever this can be avoided.
Leave the screen as close to the connectors as
possible.
The illustration shows an example of an EMC-cor-
rect electrical installation of an IP 20 frequency
converter.
The frequency converter is fitted in an installation
cabinet with an output contactor and connected
to a PLC, which is installed in a separate cabinet.
Instructions
8 | AN000086420674en-000201
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