VLT
®
8000 AQUA
■
Derating for running at low speed
When a centrifugal pump or a fan is controlled by a VLT
8000 AQUA frequency converter, it is not necessary
to reduce the output current at low speed because
the load characterstic of the centrifugal pumps/fans,
automatically ensures the necessary reduction.
For CT (Constant Torque) applications, consult motor
manufacturer for motor derating guideline based
upon operating load and duty cycle.
■
Derating for long motor cables or cables
with larger cross-section
VLT 8000 AQUA has been tested using 300m
(1000 ft) unscreened/unarmoured cable and 150m
(~500 feet) screened/armoured cable.
VLT 8000 AQUA has been designed to work using
a motor cable with a rated cross-section. Using
motor cables with cross-section area greater than
required for rated motor amps can increase cable
capacitive leakage current to earth (ground). Total
output current (motor amps + leakage amps) must
not be allowed to exceed the rated frequency
converter output current value.
■
Derating for high switching frequency
A higher switching frequency (to be set in parameter
407 -
Switching frequency)
leads to higher losses in
the electronics of the frequency converter.
VLT 8000 AQUA has a pulse pattern in which
it is possible to set the switching frequency
from 3.0- 10.0/14.0 kHz.
The frequency converter will automatically derate
the rated output current I
VLT,N
, when the switching
frequency exceeds 4.5 kHz.
In both cases, the reduction is carried out
linearly, down to 60% of I
VLT,N
.
The table gives the min., max. and factory-set
switching frequencies for VLT 8000 AQUA units.
Switching frequency [kHz]
Min.
Max.
Fact.
VLT 8006-8032, 200 V
3.0
14.0
4.5
VLT 8042-8062, 200 V
3.0
4.5
4.5
VLT 8006-8011, 480 V
3.0
10.0
4.5
VLT 8016-8062, 480 V
3.0
14.0
4.5
VLT 8072-8122, 480 V
3.0
4.5
4.5
VLT 8152-8352, 480 V
3.0
4.5
4.5
VLT 8452-8652 480 V
1.5
3.0
3.0
VLT 8002-8011, 600 V
4.5
7.0
4.5
VLT 8016-8032, 600 V
3.0
14.0
4.5
VLT 8042-8062, 600 V
3.0
10.0
4.5
VLT 8072, 600 V
3.0
4.5
4.5
VLT 8052-8352, 690 V
1.5
3.0
3.0
VLT 8402-8652, 690 V
1.5
2.0
2.0
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Motor thermal protection
The motor temperature is calculated on the basis
of motor current, output frequency and time. See
parameter 117,
Motor thermal protection.
■
Vibration and shock
VLT 8000 AQUA has been tested according to a
procedure based on the following standards:
IEC 68-2-6:
Vibration (sinusoidal) - 1970
IEC 68-2-34:
Random vibration broad-band
- general requirements
IEC 68-2-35:
Random vibration broad-band
- high reproducibility
IEC 68-2-36:
Random vibration broad-band
- medium reproducibility
VLT 8000 AQUA complies with requirements that
correspond to conditions when the unit is mounted
on the walls and floors of production premises, as
well as in panels bolted to walls or floors.
MG.83.A2.02 - VLT is a registered Danfoss trademark
188