
VLT
®
6000 HVAC Series
Introduction to
HVAC
•
Sleep mode, which automatically turns the
motor off, e.g. when there is no need for more
pressure or flow in a system.
•
The "flying start" function enables the unit
to catch a rotating fan.
•
Automatic ramp up/down to ensure that
the VLT 6000 HVAC will not trip during
acceleration or deceleration.
•
All standard units have three integral, serial protocols
- RS 485 FC protocol, Johnson
’
s Metasys N2
and Landis/Staefa Apogee FLN. Communication
option cards that can be connected are LonWorks,
DeviceNet, Modbus RTU and Profibus.
■
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 - 460 V AC, 50 / 60 Hz.
3 x 525 - 600 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
with a variable frequency.
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.
MG.61.A5.02 - VLT is a registered Danfoss trademark
9