Danfoss VLT 5000 FLUX, Руководство по эксплуатации, Страница: 9 / 158

VLT
®
5000 FLUX
Introduction
Minor interference on mains
Since as standard the frequency converter features
intermediate circuit coils, there is only a small amount
of harmonic mains supply interference. This ensures
a good power factor and lower peak current, which
reduces the load on the mains installation.
Advanced VLT protection
Current measurement on all three motor phases
provides perfect protection of the frequency
converter against earthing and short-circuiting
faults on the motor connection.
Efficient monitoring of the three mains supply phases
ensures that the unit stops in the case of phase failure.
This avoids overloading the inverter and the capacitors
in the intermediate circuit, which would dramatically
reduce the service life of the frequency converter.
As standard, the frequency converter features integral
thermal protection. If a situation of thermal overload
occurs, this function cuts out the inverter.
Reliable galvanic isolation
In the frequency converter all of the control circuits
are separated from mains potential through isolation
meeting the PELV requirements.
One set of relay contacts, terminals 01 - 03, is
separated from the remaining control circuits through
isolation also complying with PELV.
Furthermore, the control circuits are placed in blocks
individually separated through functional isolation (<
100 V), see section General Technical Data .
Advanced motor protection
The frequeny converter features integrated electronic,
thermal motor protection.
The frequency converter calculates the motor
temperature on the basis of current, frequency and time.
As opposed to the traditional bimetallic protection,
electronic protection takes account of the reduction in
cooling at low frequencies that comes from reduced
fan speed (motors with internal ventilation).
To obtain maximum protection against overheating of
the motor if the motor is covered or blocked, or if the
fan fails, a thermistor can be integrated and connected
to the thermistor input of the frequency converter
(terminals 53 or 54), see parameters 128, 308 and 311.
MG.55.A6.02 - VLT is a registered Danfoss trademark
9