VLT
®
8000 AQUA
Installation
The total current consumption of the motors
is not to exceed the maximum rated output
current I
VLT,N
for the AFD.
Problems may arise at the start and at low rpm values
if the motor sizes are widely different. This is because
the relatively high ohmic resistance in small motors 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 AFD cannot
be used as motor protection for the individual
motor. Consequently, additional motor protection
is required, such as thermistors in ground motor
(or individual thermal relays).
NOTE
Parameter 107
Automatic Motor Adaptation,
AMA
and
Automatic Energy Optimization, AEO
in parameter 101
Torque characteristics
cannot
be used motors are connected in parallel.
■
Motor cables
See
Technical data
for correct sizing of motor
cable cross-section and length.
Always comply with national and local regulations
on cable cross-sections.
NOTE
If an unshielded cable is used, some
EMC requirements are not complied with,
see
EMC test results
.
If the EMC specifications regarding emission are
to be complied with, the motor cable must be
shielded, unless otherwise stated for the RFI filter in
question. It is important to keep the motor cable
as short as possible so as to reduce the noise level
and leakage currents to a minimum.
The motor cable shield must be connected to the
metal cabinet of the AFD and to the metal cabinet of
the motor. The shield connections are to be made
with the biggest possible surface (cable clamp).
This is enabled by different installation devices in
the different AFDs. Mounting with twisted shield
ends (pigtails) is to be avoided, since these spoil
the shielding effect at higher frequencies.
If it is necessary to break the shield to install a
motor isolator or motor contactor, the shield must be
continued at the lowest possible HF impedance.
■
Motor thermal protection
The electronic thermal relay in UL-approved AFD
has received UL-approval for single motor protection,
as long as parameter 117
Motor thermal protection
has been set to ETR Trip and parameter 105
Motor
current, I
VLT,N
has been programmed for the rated
motor current (can be read from the motor nameplate).
■
Ground connection
Since the leakage currents to ground may be
higher than 3.5 mA, the AFD must always be
grounded in accordance with applicable national
and local regulations. In order to ensure good
mechanical connection of the ground cable, its
cable cross-section must be at least 8 AWG/10
mm
2
. For added security, an RCD (Residual Current
Device) may be installed. This ensures that the
AFD will cut out if the leakage currents get too
high. See RCD Instructions MI.66.AX.02.
■
Installation of 24 Volt external DC supply
Torque: 0.5 - 0.6 Nm
Screw size: M3
No.
Function
35 (-), 36 (+)
24 V external DC supply
(available with VLT 8152-8600 380-480 V only)
24 V external DC supply can be used as low-voltage
supply to the control card and any option cards
installed. This enables full operation of the LCP
(incl. parameter setting) without connection to line.
Please note that a warning of low voltage will be
given when 24 V DC has been connected; however,
there will be no tripping. If 24 V external DC supply
is connected or switched on at the same time as
the line supply, a time of min. 200 msec. must
be set in parameter 111,
Start delay
.
A pre-fuse of min. 6 Amp, slow-blow, can be
fitted to protect the external 24 V DC supply.
The power consumption is 15-50 W, depending
on the load on the control card.
MG.80.A7.22 - VLT is a registered Danfoss trademark
71
Rosewood STP ST42 General (Operation and Maintenance Manual - Part 4:
Section 6.3 Manufacturers Manuals 6.3.33 Danfoss VLT Aquadrive 8000) Vendor Manual
QP Id: VM207
Active: 03/09/2013
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