Mains Disconnects; F-Frame Circuit Breakers; F-Frame Mains Contactors; Motor Insulation - Danfoss VLT FC 302 Operating Instructions Manual

Installation

3.4.11 Mains Disconnects

Frame size
D
E
E
F
F
Table 3.9 Recommended Mains Disconnects

3.4.12 F-Frame Circuit Breakers

Frame size
F
F
Table 3.10 Recommended Circuit Breakers

3.4.13 F-Frame Mains Contactors

Frame size
F
F
Table 3.11 Recommended Contactors

3.4.14 Motor Insulation

For motor cable lengths ≤ the maximum cable length, the
motor insulation ratings listed in Table 3.12 are
recommended. The peak voltage can be twice the DC-link
voltage or 2.8 times mains voltage, due to transmission
line effects in the motor cable. If a motor has lower
insulation rating, use a dU/dt or sine wave filter.
Nominal Mains Voltage Motor Insulation
≤ 420 V
U Standard U
N
420 V < U ≤ 500 V Reinforced U
N
Table 3.12 Recommended Motor Insulation Ratings

3.4.15 Motor Bearing Currents

Motors with a rating 110 kW or higher combined with
frequency converters are best with NDE (Non-Drive End)
insulated bearings to eliminate circulating bearing currents
caused by motor size. To minimise DE (Drive End) bearing
and shaft currents, proper grounding is required for:
•
Frequency converter
•
Motor
•
Motor-driven machine
•
Motor to the driven machine

MG37A202

Operating Instructions
Power & Voltage
P132-P200 380–500 V
P250 380-500 V
P315-P400 380-500 V
P450 380-500 V
P500-P630 380-500 V
Power & Voltage
P450 380-500 V
P500-P630 380-500 V
Power & Voltage
P450-P500 380-500 V
P560-P630 380-500 V
= 1,300 V
LL
= 1,600 V
LL
Danfoss A/S © Rev. 2014-07-29 All rights reserved.
Type
OT400U12-9 or ABB OETL-NF400A
ABB OETL-NF600A
ABB OETL-NF800A
Merlin Gerin NPJF36000S12AAYP
Merlin Gerin NRK36000S20AAYP
Merlin Gerin NPJF36120U31AABSCYP
Merlin Gerin NRJF36200U31AABSCYP
Type
Eaton XTCE650N22A
Eaton XTCEC14P22B
Although failure due to bearing currents is infrequent, use
the following strategies to reduce the likelihood:
•
Use an insulated bearing
•
Apply rigorous installation procedures
•
Ensure that the motor and load motor are
aligned
•
Strictly follow the EMC Installation guideline
•
Reinforce the PE so the high frequency
impedance is lower in the PE than the input
power leads
•
Provide a good high frequency connection
between the motor and the frequency converter
•
Ensure that the impedance from frequency
converter to building ground is lower than the
grounding impedance of the machine. Make a
direct ground connection between the motor and
load motor.
•
Apply conductive lubrication
•
Try to ensure that the line voltage is balanced to
ground.
•
Use an insulated bearing as recommended by the
motor manufacturer (note: Motors from reputable
manufacturers typically have insulated bearings
as standard in motors of this size)
Type
29
3 3