VLT® 5000 Crane
Introduction
Minor interference on mains
Since as standard the VLT 5000 Crane 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 VLT 5000 Crane
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, VLT 5000 Crane features integral
thermal protection. If a situation of thermal overload
occurs, this function cuts out the inverter.
Encoder supervisory circuit
The signals from the incremental encoder and hence
the cabling are continuously supervised.
The encoder signals are made up of three channels,
each of which are supervised, and status is given
on LEDs placed near the encoder terminals for each
channel as well as for the supply voltage for the encoder.
Green LED turned on means channel or voltage OK.
Reliable galvanic isolation
In the VLT 5000 Crane 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 General Technical Data.
Advanced motor protection
VLT 5000 Crane 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), see parameters 128 and 308.
MG.50.N4.02 - VLT is a registered Danfoss trademark
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