Motor Insulation; Motor Bearing Currents - Danfoss VLT HVAC Drive FC 102 Instruction Manual

Electrical Installation
Enclosure size
E1/E2
E1/E2
F3
F3
F4
4 4
Table 4.25 Line Power Disconnectors Enclosure Sizes E and F
Enclosure size
F3
F3
F4
F4
Table 4.26 Circuit Breakers Enclosure Size F
Enclosure size
F3
F3
F4
Table 4.27 Line Power Contactors Enclosure Size F

4.1.15 Motor Insulation

For motor cable lengths ≤ the maximum cable length
listed in chapter 7 General Specifications, the recommended
motor insulation ratings are in Table 4.28. The peak voltage
can be up to twice the DC link voltage, 2.8 times the AC
line voltage, due to transmission line effects in the motor
cable. If a motor has a lower insulation rating, use a dU/dt
or sine-wave filter.
Nominal AC line voltage
≤ 420 V
U
N
420 V < U ≤ 500 V
N
500 V < U ≤ 600 V
N
600 V < U ≤ 690 V
N
Table 4.28 Motor Insulation at Various Nominal AC Line
Voltages

4.1.16 Motor Bearing Currents

For motors with a rating of 110 kW (150 hp) or greater
that operate via adjustable frequency drives, use NDE
(Non-Drive End) insulated bearings 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 adjustable frequency drive, motor, driven
machine, and motor to the driven machine is required.
54
®
VLT HVAC Drive FC 102
Power and voltage
P315 380-480 V & P450-P630 525–690 V
P355-P450 380–480 V
P500 380-480 V & P710-P800 525–690 V
P560-P710 380–480 V & P900 525–690 V
P800-P1M0 380–480 V & P1M0-P1M4 525–690 V
Power and voltage
P500 380–480 V & P710-P800 525–690 V
P560-P710 380–480 V & P900 525–690 V
P800 380–480 V & P1M0-P1M4 525–690 V
P1M0 380–480 V
Power and voltage
P500-P560 380–480 V & P710-P900 525–690 V
P 630-P710 380–480 V
P800-P1M0 380–480 V & P1M0-P1M4 525–690 V
Motor insulation
Standard U = 1300 V
LL
Reinforced U = 1600 V
LL
Reinforced U = 1800 V
LL
Reinforced U = 2000 V
LL
Danfoss A/S © 08/2014 All rights reserved.
ABB OT600U03
ABB OT800U03
Merlin Gerin NPJF36000S12AAYP
Merlin Gerin NRK36000S20AAYP
Merlin Gerin NRK36000S20AAYP
Merlin Gerin NPJF36120U31AABSCYP
Merlin Gerin NRJF36200U31AABSCYP
Merlin Gerin NRJF36200U31AABSCYP
Merlin Gerin NRJF36250U31AABSCYP
Eaton XTCE650N22A
Eaton XTCEC14P22B
Eaton XTCEC14P22B
Although failure due to bearing currents is rare, if it occurs,
use the following mitigation strategies.
Standard mitigation strategies:
•
Use an insulated bearing.
•
Apply rigorous installation procedures:
- Ensure that the motor and load motor
are aligned.
-
Strictly follow common EMC installation
guidelines.
- 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
adjustable frequency drive by shielded
cable. The cable must have a 360°
connection in the motor and adjustable
frequency drive.
- Ensure that the impedance from
adjustable frequency drive 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.
Type
Type
Type
MG11F522