5.8.3 Discharge Resistors
There are common positive and negative DC terminals on each drive module. If a shorter time to achieve the reduced run
functionality is wanted, connect the external discharge resistor for quicker discharge of DC-link voltage. It is possible to
connect a discharge resistor in an additional cabinet, through a contactor. This discharge contactor should have an interlock
with the mains contactor/disconnector’s auxiliary NC contacts to avoid a discharge when the drive system is powered.
shows a 4-drive system with discharge resistor connections.
Base the selection of a discharge resistor on the energy and power levels given in
for different power sizes, on
both 12-pulse and 6-pulse systems.
FC 102
FC 202
N500
N560
N630
N710
N800
N1M0
FC 302
N450
N500
N560
N630
N710
N800
Drive modules required
(HO rating)
2xN250
4xN160
4xN200
4xN200
4xN250
4xN250
Resistance required to reduce DC
voltage below 50 V within 300 s
(5 minutes),
Ω
3036
2277
1822
1822
1518
1518
Power rating of resistor (W)
182
242
303
303
363
363
Energy dissipated by resistor (J)
7773
10365
12956
12956
15547
15547
Table 5.12 Discharge Resistors Recommended for Drive Systems with 380–480 V AC Mains Supply
FC 102
FC 202
N630
N710
N800
N900
N1M0
N1M2
FC 302
N560
N630
N710
N800
N900
N1M0
Drive modules required
(HO rating)
2xN315
4xN200
4xN250
4xN250
4xN315
4xN315
Resistance required to reduce DC
voltage below 50 V within 300 s
(5 minures),
Ω
4571
3047
2285
2285
2285
2285
Power rating of resistor (W)
230
345
459
459
459
459
Energy dissipated by resistor (J)
8819
13229
17638
17638
17638
17638
Table 5.13 Discharge Resistors Recommended for Drive Systems with 525–690 V AC Mains Supply
NOTICE
Danfoss is not responsible for any failure or malfunction of the resistor, or for any misconnections made by the installer.
NOTICE
The wire used with the brake resistor should be double-insulated or have reinforced insulation.
Electrical Installation
VLT
®
Parallel Drive Modules
30
Danfoss A/S © 08/2017 All rights reserved.
MG37K302
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