Danfoss VLT AQUA Drive FC 200 Operating Instructions Manual page 58

VLT AQUA Low Harmonic Drive Operating In-
structions
4.6.15 Mains Disconnectors - Frame Size D, E and F
Frame size
D
E
E
F
F
4.6.16 F Frame circuit breakers
Frame size
F
F
4.6.17 F Frame Mains Contactors
Frame size
F
F3
4.6.18 Motor Insulation
For motor cable lengths ≤ the maximum cable length listed in the General
Specifications tables the following motor insulation ratings are recom-
mended because the peak voltage can be up to twice the DC link voltage,
2.8 times the mains voltage, due to transmission line effects in the motor
cable. If a motor has lower insulation rating it recommended to use a du/
dt or sine wave filter.
4.6.19 Motor Bearing Currents
It is generally recommended that motors of a rating 110kW or higher operating via Variable Frequency Drives should have NDE (Non-Drive End) insulated
bearings installed to eliminate circulating bearing currents due to the physical size of the motor. To minimize DE (Drive End) bearing and shaft currents
proper grounding of the drive, motor, driven machine, and motor to the driven machine is required. Although failure due to bearing currents is low and
very dependent on many different items, for security of operation the following are mitigation strategies which can be implemented.
Standard Mitigation Strategies:
1. Use an insulated bearing
2. Apply rigorous installation procedures
Ensure 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 for instance by screened cable which has a 360°
connection in the motor and the frequency converter
Make sure that the impedance from frequency converter to building ground is lower that the grounding impedance of the machine. This can be
difficult for pumps- Make a direct earth connection between the motor and load motor.
Power & Voltage
P160-P250 380-480V
P315 380-480V
P355-P450 380-480V
P500 380-480V
P560-P710 380-480V
Power & Voltage
P500 380-480V
P560-P710 380-480V
Power & Voltage
P500-P560 380-480V
P 630-P710 380-480V
®
MG.20.T1.02 - VLT is a registered Danfoss trademark
Type
OT400U12-91
ABB OETL-NF600A
ABB OETL-NF800A
Merlin Gerin NPJF36000S12AAYP
Merlin Gerin NRK36000S20AAYP
Type
Merlin Gerin NPJF36120U31AABSCYP
Merlin Gerin NRJF36200U31AABSCYP
Type
Eaton XTCE650N22A
Eaton XTCEC14P22B
Nominal Mains Voltage Motor Insulation
≤ 420 V
U Standard U
N
420 V < U ≤ 500 V Reinforced U
N
4 How to Install
4
= 1300 V
LL
= 1600 V
LL
57