Ce Compliance; Ul Compliance; Output: Motor-Side Dynamics; Motor Connection - Danfoss VLT Decentral Drive FCD 302 Design Manual

System Integration

3.2.2.3 CE Compliance

Use of fuses or circuit breakers is mandatory to comply
with IEC 60364.
Danfoss recommends fuse size up to gG-25. This fuse size
is suitable for use on a circuit capable of delivering
100,000 Arms (symmetrical), 480 V. With the proper fusing
the frequency converter short circuit current rating (SCCR)
is 100,000 Arms.

3.2.2.4 UL Compliance

Fuses or Circuit Breakers are mandatory to comply with
NEC 2009. To meet UL/cUL requirements, use the pre-fuses
in Table 6.3, and comply with the conditions listed in
6.2 Electrical Data and Wire Sizes.

3.3 Output: Motor-side Dynamics

3.3.1 Motor Connection

NOTE
To comply with EMC emission specifications, screened/
armoured cables are recommended.
See 6.3 General Specifications for correct dimensioning of
motor cable cross-section and length.
Screening of cables
Avoid installation with twisted screen ends (pigtails). They
spoil the screening effect at higher frequencies. If it is
Term. no. 96 97
U V
U1 V1
W2 U2
U1 V1
Table 3.4 Motor Connection Terminals
1) Protected Earth Connection
®
VLT Decentral Drive FCD 302
98 99
W 1) Motor voltage 0-100% of mains voltage.
PE
3 wires out of motor
W1 Delta-connected
1)
PE
V2 6 wires out of motor
W1 1) Star-connected U2, V2, W2
PE
U2, V2 and W2 to be interconnected separately.
®
MG04H102 - VLT is a registered Danfoss trademark
necessary to break the screen to install a motor isolator or
motor contactor, the screen must be continued at the
lowest possible HF impedance.
Connect the motor cable screen to both the decoupling
plate of the frequency converter and to the metal housing
of the motor.
Make the screen connections with the largest possible
surface area (cable clamp). This is done by using the
supplied installation devices in the frequency converter.
If it is necessary to split the screen to install a motor
isolator or motor relay, the screen must be continued with
the lowest possible HF impedance.
Cable-length and cross-section
The frequency converter has been tested with a given
length of cable and a given cross-section of that cable. If
the cross-section is increased, the cable capacitance - and
thus the leakage current - may increase, and the cable
length must be reduced correspondingly. Keep the motor
cable as short as possible to reduce the noise level and
leakage currents.
All types of three-phase asynchronous standard motors can
be connected to the frequency converter. Normally, small
motors are star-connected (230/400 V, Y). Large motors are
normally delta-connected (400/690 V, Δ). Refer to the
motor name plate for correct connection mode and
voltage.
For installation of mains and motor cables refer to FCD 302
Operating Instructions, MG04F.
U V W
96 97 98
Illustration 3.7 Star - Delta Earth Connections
U V W
96 97 98
31
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