13
VLT
®
3500 HVAC
MG.35.B1.02 – VLT is a registered Danfoss trademark
Section 1Section 1Section 1Section 1Section 1
Section 2Section 2Section 2Section 2Section 2
Section 3Section 3Section 3Section 3Section 3
Section 4Section 4Section 4Section 4Section 4
Warning:
The frequency converter voltage is
dangerous when connected to mains
and up to 14 minutes after the unit has
been disconnected. Electrical installa-
tion is therefore only to be carried out by a qualified
electrician.
Incorrect mounting of the motor or the frequency con-
verter may result in damge to the equipment, serious
personal injury or death. Consequently, the instruc-
tions of this Design Guide must be complied with,
together with national and local safety regulations.
NB!:
NB!:
NB!:
NB!:
NB!:
It is the responsibility of the user or the elec-
trician to ensure that protection against earthing
is established in accordance with applicable na-
tional and local standards.
Pre-fuses
For VLT type 3502-3562 external pre-fuses must be
installed in the power supply for the frequency con-
verter.
Correct size and dimensioning can be seen from the
section on technical data, pages 5-7.
For VLT type 3575-3800 HVAC, 380/500 V and VLT
3542-3562 HVAC, 230V, the pre-fuses are included in
the mains connection of the frequency converter.
General
The terminals for both the 3-phase mains supply and
the motor are placed in the lower half of the enclosure
of the frequency converter.
The motor cable screen is connected to both the
frequency converter and the motor. The frequency
converter has been tested using a given length of
screened cable and a specific cross-section. If the
cross-section is increased, the discharge capacity of
the cable goes up and so does the discharge current.
This means that the cable must be shortened corre-
spondingly.
The electronic thermo relay (ETR) cannot be used if
the motors operate in parallel. ETR has been UL
approved for operating individual motors - when para-
meter 315 has been set to trip, parameter 311 has
been set to 0 sec., and parameter 107 has been
programmed to match the rated motor (nameplate)
current.
Mains and motor connection for VLT 3502-3562
HVAC, 200/380/500 V (not 3542-3562, 230 V)
The max. cable cross-section and the corresponding
max. length and terminal size can be seen from the
section on technical data, pages 5-7.
The mains supply and the motor are connected in
accordance with the drawing below.
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2.4 Electrical installation
Mains
Motor
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Extra protection
Earth fault voltage relays, protective multiple earthing
or protective grounding can be used as extra protection.
However, such an installation must comply with local
health and safety standards.
An earth fault can introduce a DC current in the dis-
charge current.
If FI relays are used, local regulations must be
complied with.
The relays must be suitable for protecting 3-phase
equipment with bridge rectifier and a short discharge
on power-up.
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Electrical installation
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