AKD 2800
Installation
■
RFI switch
Mains supply isolated from earth:
If the frequency converter is supplied from an isolated
mains source (IT mains), the RFI switch can be
turned off (OFF). In OFF position, 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).
NB!:
The RFI switch is not to be operated with
mains connected to the unit. Check that
the mains supply has been disconnected
before operating the RFI switch.
NB!:
The RFI switch disconnects the capacitors
galvanically from ground.
The switch Mk9, placed next to terminal 96, should
be removed to disconnect the RFI-filter.
The RFI switch is only available on AKD 2880-2882.
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Direction of motor rotation
The factory setting is for clockwise rotation
with the frequency converter transformer output
connected as follows:
Terminal 96 connected to U-phase.
Terminal 97 connected to V-phase.
Terminal 98 connected to W-phase.
The direction of rotation can be changed by switching
two phases on the motor terminals.
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Parallel connection of motors
The frequency converter is able to control several
motors connected in parallel. If the motors are
to have different rpm values, use motors with
different rated rpm values. Motor rpm is changed
simultaneously, which means that the ratio between
the rated rpm values is maintained across the range.
The total current consumption of the motors is
not to exceed the maximum rated output current
I
INV
for the frequency converter.
Problems may arise at the start and at low rpm
values if the motor sizes are widely different. This
is because the small motors
’
relatively high ohmic
resistance in the stator calls for a higher voltage
at the start and at low rpm values.
In systems with motors connected in parallel, the
electronic thermal relay (ETR) of the frequency
converter cannot be used as motor protection
for the individual motor. For this reason further
motor protection must be used, e.g. thermistors in
each motor or an individual thermal relay. (Circuit
breakers are not suitable as protection).
NB!:
Parameter 107
Automatic motor adaption, AMT
cannot be used when motors are connected
in parallel. Parameter 101
Torque characteristic
must be set to
Special motor characteristics
[8]
when motors are connected in parallel.
MG.28.H2.02 -
53