Danfoss VLT 8000 AQUA series User Manual

VLT
®
8000 AQUA
■ Control principle
A frequency converter rectifies AC voltage from
mains into DC voltage, after which this DC
voltage is converted into a AC current with a
variable amplitude and frequency.
The motor is thus supplied with variable voltage and
frequency, which enables infinitely variable speed
control of three-phased, standard AC motors.
1. Mains voltage
3 x 200 - 240 V AC, 50 / 60 Hz.
3 x 380 - 480 V AC, 50 / 60 Hz.
3 x 525 - 600 V AC, 50 / 60 Hz.
3 x 525 - 690 V AC, 50 / 60 Hz.
2
. Rectifier
A three-phase rectifier bridge that rectifies AC
current into DC current.
3
. Intermediate circuit
DC voltage = 1.35 x mains voltage [V].
4
. Intermediate circuit coils
Even out the intermediate circuit voltage
and reduce
the harmonic current feedback to the mains supply.
5
. Intermediate circuit capacitors
Even out the intermediate circuit voltage.
6
. Inverter
Converts DC voltage into variable AC voltage
withavariablefrequency.
7
. Motor voltage
Variable AC voltage, 0-100% of mains supply voltage.
8
. Control card
This is where to find the computer that controls
the inverter which generates the pulse pattern by
which the DC voltage is converted into variable
AC voltage with a variable frequency.
■ AEO - Automatic Energy Optimization
Normally, the U/f characteristics have to be set on the
basis of the expec
ted load at different frequencies.
However, knowing the load at a given frequency in an
installation is often a problem. This problem can be
solved by usin
g a VLT 8000 AQUA with its integral
Automatic Energy Optimization (AEO), which ensures
optimum energy utilization. All VLT 8000 AQUA units
feature thi
s function as a factory setting, i.e. it is
not necessary to adjust the frequency converter U/f
ratio in order to obtain maximum energy savings.
In other
frequency converters, the given load and
voltage/frequency ratio (U/f) must be assessed to carry
out correct setting of the frequency converter.
Using A
utomatic Energy Optimization (AEO), you
no longer need to calculate or assess the system
characteristics of the installation, since Danfoss VLT
800
0 AQUA units guarantee optimum, load-dependent
energy consumption by the motor at all times.
The figure on the right illustrates the working
range of the AEO function, within which energy
optimization is enabled.
If t
he AEO function has been selected in parameter 101,
Torque characteristics, this function will be constantly
active. If there is a major deviation from the optimum U/f
r
atio, the frequency converter will quickly adjust itself.
Advantages of the AEO function
• Automatic energy optimization
• Compensation if an oversize motor is used
• AEO matches operations to daily or
seasonal fluctuations
MG.83.A2.02 - VLT is a registered Danfoss trademark
10

Danfoss VLT 8000 AQUA series Specifications

General

Brand	Danfoss
Model	VLT 8000 AQUA series
Category	DC Drives
Language	English