GE AF-600 FP Series, Руководство по эксплуатации

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3.1.2 Earthing
The following basic issues need to be considered when
installing a frequency converter, so as to obtain electro-
magnetic compatibility (EMC).
•
Safety earthing: Please note that the frequency
converter has a high leakage current and must be
earthed appropriately for safety reasons. Apply
local safety regulations.
•
High-frequency earthing: Keep the earth wire
connections as short as possible.
Connect the different earth systems at the lowest possible
conductor impedance. The lowest possible conductor
impedance is obtained by keeping the conductor as short
as possible and by using the greatest possible surface area.
The metal cabinets of the different devices are mounted
on the cabinet rear plate using the lowest possible HF
impedance. This avoids having different HF voltages for
the individual devices and avoids the risk of radio
interference currents running in connection cables that
may be used between the devices. The radio interference
will have been reduced.
In order to obtain a low HF impedance, use the fastening
bolts of the devices as HF connection to the rear plate. It is
necessary to remove insulating paint or similar from the
fastening points.
3.1.3 Extra Protection (RCD)
ELCB relays, multiple protective earthing or earthing can
be used as extra protection, provided that local safety
regulations are complied with.
In the case of an earth fault, a DC component may
develop in the fault current.
If ELCB relays are used, local regulations must be observed.
Relays must be suitable for protection of 3-phase
equipment with a bridge rectifier and for a brief discharge
on power-up.
See also the section Special Conditions in the Design Guide.
3.1.4 Drives with Factory installed A1/B1
RFI Filter Option:
Mains supply isolated from earth
If the frequency converter is supplied from an isolated
mains source ( IT mains, floating delta and grounded delta)
or TT/TN-S mains with grounded leg, the RFI switch is
recommended to be turned off (OFF) via
SP-50 RFI Filter on
the drive and SP-50 RFI Filter on the filter. For further
reference, see IEC 364-3. In case optimum EMC
performance is needed, parallel motors are connected or
the motor cable length is above 25 m, it is recommended
to set
SP-50 RFI Filter to [ON].
In OFF, the internal RFI capacities (filter capacitors)
between the chassis and the intermediate circuit are cut
off to avoid damage to the intermediate circuit and to
reduce the earth capacity currents (according to IEC
61800-3).
It is important to use isolation monitors that are capable
for use together with power electronics (IEC 61557-8).
3.1.5 Torque
When tightening all electrical connections it is very
important to tighten with the correct torque. Too low or
too high torque results in a bad electrical connection. Use
a torque wrench to ensure correct torque
Illustration 3.11 Always use a torque wrench to tighten the
bolts.
Unit Size Terminal Torque Bolt size
41, 42, 43 and
44
Mains
Motor
19-40 Nm
(168-354 in-
lbs)
M10
51 and 52 Mains
Motor
19-40 Nm
(168-354 in-
lbs)
M10
61, 62, 63 and
64
Mains
Motor
19-40 Nm
(168-354 in-
lbs)
M10
Table 3.1 Torque for terminals
3.1.6 Shielded Cables
It is important that shielded and armoured cables are
connected in a proper way to ensure the high EMC
immunity and low emissions.
The connection can be made using either cable glands or
clamps:
•
EMC cable glands: Generally available cable
glands can be used to ensure an optimum EMC
connection.
•
EMC cable clamp: Clamps allowing easy
connection are supplied with the frequency
converter.
Electrical Installation AF-600 FP High Power Operating Instructions
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